FUNGI PARASITIC UPON ALEYRODES CITRI By HOWARD S. FAWCETT A THESIS FOR THE DEGREE OF MASTER OF SCIENCE SUBMITTED TO THE FACULTY OF Pin RSkhy OF THE STATE Ol FEORID: JUNE, 1908. UNIVERSITY OF THE STATE OF FLORIDA SPECIAL Stupiges No. 1 ee . —*h ¥ | CONTENTS: PAGE. IETS RONDO CTSTOUNY Qs concn aee eeRGE Nes Win CRI UAC coer aR oye rhachis irs ne. trend ae Sea 5 Statement of Work on Which the Dhesis 1s \Baseds.....-+..s..0+-+.-- 0. -- 5 Historical "Review of Entomogenous, Bunpiyy suecec- ass Soe. ees 5 Historical Review and Economic Status of Aleyrodes citri R. & H......... 8 i VASCHERSONDA: VALEV-RODIS, WEBBER s s1 seis c-icue ors, shave ae eters eurbats cueing Cheleme cle ate 10 Discovery andwiDeseriptiOnimemrev cress ase eet tuseee Re achermertoromicn trees 10 FAGSEORYS aa ineseie correc ces de Peed hasan stat nae Mal apes Rowen As, Batol aes Sip eae 10 Miethods’ of intno dictions ss. 5. caccis lectin otc eet ASRS yes GEE cota ocho meis ae 11 Gerniinati on sot: vConiiante rec: cae hes eT Oe ens ae ear eee 12 Cult ie Sees re Areas aces Raut won Stems ECU Seats ATM RPS ee Noro acTe eee wee eR Cer 3 IinfectionwoteAleyrodesmcitin prone GtilbumeSemcra sacra etic ena) terior tae 16 DASE DUET OT coves sav: Seca ake mea sc TSN eee ee er ne Mts Sire aa restate ro eR OTS 17 JEM, ASSETS QSONNON THEAORGIMRINWN 12% TAWBININS od ooac0 bo cur Q0c00 995 6000bobDaGCO0db or 17 IDISCoNeay Aine! IDESSBINNOM os oonagaeso Dosoomape coodccdu eeDod Doo UCU ba moO b DE ali Conmipanisonvwith As aleynodiis.seycackcocncee ee nee Sheea Gs Se ie Sei cca yore era 18 Gn e Ss See eee A es acs Aetaereces aE Mca Ge nae eM atAET syste ens eae tee cae eee 18 CErmannninron one (Crormaligh o okede soe demco hod oudbbcce duc. aubaocnooe dunno cade: 19 SUperspanasivecee tsa So cate tikes Macpac Nee ae can gee cee okt aimee eeertcyege: ere 21 Wistwoteleocalitiesrimeb Oni Gar ac circ: eeomie oe omer eecentine re ier tole wit 21 IW, | WASRTCTIEEONE: TENSNINOOLAMUIN. IPRA Gena n cob onaoueco pons pUOogudee a OuooUD TOO 21 IDigeonemy cil ISbiQtoie copobemone cass codousoy cotdcco gn bONueoODOO DUD ODO meme 21 IDYSXSIDIOGN IIS ec oneeenha .ciccis.c Orne Casio ee mee eecl Cao leo cca bin,cinicncie © Oa ormic 0 oF Or ola Go 22 Glin subi coi eo Sree pene tees Rasher cot Gearon: naan nc sas HORSE ber caer Roe erenen acre 23 (SGnriharyaornt onal Comiiabitinas odewaroeecdccnle acpoddosuud Goaducnbood Od eoacoGe 24 Immbectionon Aleyrodes citni trom Culttinese. ee = scamee ae cleo tienen rh tot 24 IAistorelmsectsmearasiize dae within Oca lites armenian inert netl torte tT rar 25 We, Sirecnosinnems (orectosmin. Aitas cosuscdeccouudosuvocnen coon chou Cou De ONsS 25 IDSC Sho ator ue eee RNS iene coctord Ani bro chcreolot ta Biomima a die bio culusmno-0 G-0c 25 ISO) a eee ae Sa ee ie OE IGE MPR RNS Ao e289 aE OE BTN cm dic Se 26 Relation toroam jose and (Other Scaleslnsectsea..y pene oe eee on Paveaistincian Oral /NIGSACOVGIES (GlliiriLacoadsodoseovodussdoonsog —etuduanvcaccacmouc 28 Iisteor insects! (Parasitized: wath I OcalliitieSm.ei ee tot ost taetent aeense eens 29 Vale BONITO OCHRIAUES Ps payee ae warcecedarls sates, eyceuatts ce tts eoageisnctn euehewee tay Wrens eons ola Retee tac ucr oot 29 ARechini cals DESeriptl Oni nc faassen 2 bcaiecke es Meaney eee eae vedere Taser ee le 29 IDiScohi Gina Cal aatercad Go dene yore eee MRS TIA Siac e eS oaths BINH ON OOO OO LS Gas OF 30 (@uillietge Shaagercrwee eee ees eaten goa ee Se DEM ins Eee cng se seroinis ig) oSRg EC 30 Imfection on Alleyrodes citrt dnomtCullittres:csassaeee acco sce ei na 32 (Gamanimetsiorn or (Coriclie) soacenotonoe coe apcesbonooe once qoobacuodancndccd bee 33 Waiiainorn aa sae Or CominGlies oouomscncsnon bouauddquonsn coddcunduon OD OUOS DDE 33 IDNiSiemlbELONm ata TelKoGE, Vata Reg aeocoumaocvaneccaqdod ldioncodedncodue oom 34 AVelilin Melb eTIen S ERRONV Naa Et UINUG Wh ieenncee ette. aster esac Gaicr ol secre orcs Orca eee Getty Siete sol soe cee 34 IDISC OME Taye See iceoicnctat eter eeeen areca rete eae nce PRO Shel sede tte alts NGeiGS salesaws erage eto ohare aot 34 IDeceiripisiorm: ye WWE DSe nooo ecumon Goede denabonocn boc do aeGocuouuopen Tl omoas 34 BRON ar a RHUNEAEIS Oie IESE GiNoeo oie ous 650 Co noUridoooUcue bono OsoDeaandooo.c00 cbc 35 Wisaneals. Gir InibROGhiCnON song oadebugoon en podbean uob alco Oee cee gucoudoo Sener 39 IDNigiieil SIMON oto pee dos no ea Oe deemed ocolcertta conan mand Comodume tad 36 SD ANE NIV INOS. Belcan me Dee OU bE em bea Ome lao nn Dona BiG Don MORI 6 aba b owtsatrot 36 SHGAMENENEAG & aR Ee Oa ic cr RARER Ee SEN En arene MEM cera 37 IBUBIGIOCR AREY ees ee ae ORES Ae eo: tacts, nial ae tee loko ake che ETE ed. BR TARP IE En aa Noire Atenas 38 EXPLANATION OF PLATES...... ee Per EL eee LCA RIG EMCO Oe ETERS aE OIA D Poa OREO 41 LIST OF Meg St RAMON S: PAGE. ree Cub iaaholhe eualalatoete Cope wali Als Velitdise Shah o sacs Goss apackcdsaccacT facing 8 Fig. 2.—Larvae and pupae of Aleyrodes ctirt........+--0.-25 eee eee s ene: facing 9 Hiss 3——Comidia Of Aschersonia GleyrOt ssa .yo initia eri telnet ey percent: 12 Fig. 4—Conidium of Aschersonia aleyrodis germinating..........---..+++++.+5-- 133 Fig. 5.—Hyphae of Aschersomia flavo-citrind.......... 00.22. eee eee ee 19 Fig. 6.—Conidia of Aschersonita flavo=cutrind.. 5.02.2 nosis oe oe ti 19 Figs. 7, 8 and 9—Sporids of Aschersomia flavo-citrina.........--++++- 020+ -s eee 20 Fig, 10—Conidiophores and conidia of Verticilliwm heterocladum.........+..++++: 23 Fig. 11.—Spore-like bodies of Verttcillium heterocladum...........--.-.-+++----- 23 Fig. 12.—Perithecium of Sphaerostilbe coccophila.......-- +223 22 0 eee 25 ie 132 Ascus of SPpuaerOstilbe COCCOPIMUG . 5.x iisate lo) eae eleennioe = nial eeh a ee 25 Fig. 14—Sporodochium of Sfheerostilbe coccophila...:.......02 seen cue eee ne: 26 Riots —-Comidia of SpHaerostilbe COCCOPWU Graz ais cea ci. aries eileen 26 Pies 16—Elyphacand conidia on Macrocena Spc. .iels est lene icirtcis ets ede eara 30 lenis, il (Conacher on WMG GROG Seo oocccuuecseocdadsoboocuDd sonossosnnascogooser 30 io 18 —Conidia on LMicrocera Sp.sse eee ace said Se olarchete ool oh teekce eh eee lea rene 30 Bis. 19—-Sporids of Microcera-~ Spx 2a. coe one). wale eet ae oe ache eit reheat 33 Figs. 20, 21, 22 and 23.—Cultures of Aschersonia aleyrodis.........+++++++++0> Plate I bis, 24-—Aschersoma flavo-citrina on Citrus leat... 5... 2a. eee ere Plate Il Bis, 25.—Alschersoma aleyrodis on Citrtis leaf... 1. 20. one ee ele eis ne Plate IL Figs. 26 and 27.—Cultutes of Aschersoma flavo-citrinad...........+.+:+-++--- Plate II] Figs. 28, 29 and 30.—Cultures of Aschersonta flavo-citrina................... Plate IV Fig. 31 —Verticillunn heterocladum on Citrus leat. .....--402-425-6 5255 JleneS. IAW Figs. 32,33 and 34.—Cultures of Verticillium heterocladum..............-.... Plate V Fig. 35.—Verticiliium heterocladum On leahcc cs oR theeete eee ee eee Plate V Fig. 36—Sphaerostilbe coccophila on Aspidiotus hederae...........-....-+- Plate VI Figs. 37 and 38.—Sphaerostilbe coccophila on Mytilaspis citricola............ Plate VI igs, 39 and 40.—Cultures of Microcena Spin. onc) ee ae ees Plate VI Fig. 41.—MWicrocera’ sp. on Citrus. leatico. ston \.o. sees eee eee ee eae Plate Vi Figs, 42.— Brown uneus om Citrus: leat see eee iene ae eereeeee er eee Pilate vel ms 1) Q g¢. 43.—Super-parasite on Aschersonia flavo-citvrina..............-++++-+:- Plate Vil FUNGI PARASITIC UPON ALEYRODES CITRI. BY Howarp 8S. FAWCETT, Plant Pathologist, Florida Agricultural Experiment Station. I. INTRODUCTION. Since taking up the investigation of Citrus diseases in the fall of 1905, in connection with work in the Florida Experiment Station, the author has given considerable attention to the study of the fungi parasitic on Aleyrodes citri R. & H., and on scale insects. Since the beginning of the work three species of fungi have been discovered to be parasitic upon the larvae and pupae of Aleyrodes citri; two of these, Aschersonia flavo-citrina, and an undetermined species of Microcera, were first noticed by Prof, P. H. Rolfs, and the third, Verticillium heterocladum, by the author. With the addition of these three, the number of known fungus parasites of this insect is in- creased to six, namely: 1. Aschersonia aleyrodis Webber, 2. Aschersona flavo-citrina P. Henn., 3. Verticillium heterocladum Penz., 4. Sphacrostilbe coccophila Tul., Microcera sp., 6. The sterile Brown fungus of Webber. Or Cultures of all these fungi except the Brown fungus have been grown in the laboratory by the author. One of these, Sphaerostilbe coccophila, had been previously studied in pure cultures by P. H. Rolfs, who published his results in Bulletin 41 of the Florida Experiment Station under the title of “A Fungus Disease of the San Jose Scale’. For this reason a further study of this fungus in cultures was not undertaken, and it is, moreover, only rarely parasitic upon Aleyrodes citri. It is the purpose of this thesis, after a brief review of previous investiga- tions of the fungus parasites of insects, to describe the results of recent study of the fungi that are parasitic upon Aleyrodes citri in Florida. With the description of each fungus there is given its distribution and the names of its insect hosts. A bibliography of the six fungi is added. The illustrations, except Figs. 1, 2, and 42, are original. Technical descriptions and a general review of previous literature, when any such has been published, are in- cluded with the account of each fungus. ENTOMOGENOUS FUNGI. The fact that certain low forms of plant growth, such as fungi and bacteria, are at times the cause of the destruction of great numbers of insects, has created much popular as well as scientific interest for many 6 FUNGI PARASITIC UPON ALEYRODES CITRI. years. As early as 1754, according to M. C. Cooke,! a popular description was written by Father Torrubia of a fungus growing out from the bodies of wasps. Father Torrubia had collected specimens of this at Havana, Cuba, as early as 1749. Cooke thinks that this fungus was Cordyceps specocephala. He quotes Torrubia’s account from Edwards’ ‘Gleanings in Natural History,” published in 1758, and says that this species represents the rather celebrated vegetable wasp which had a romantic history a century before. Cooke also gives an account of a species of Isaria, which had been known as early as 1782 on the Sphinx moth.t He mentions as many as 197 species, representing 39 genera of fungi, that have been found growing upon various insects. ‘The majority of these species are included by Cooke under 5 genera: Cordyceps, with 48 species; Laboulbenia, with 34 species; Isaria, with 24 species; Entomophthora, with 22 species; and Empusa, with 13 species. Since then many new genera have been added to the ento- mogenous fungi. Species of Cordyceps found on wasps, bees, ants, cater- pillars, and scale insects, have been mentioned by many scientists and popular writers from the last-mentioned date down to the present time. Cooke refers to the “History of Insects” by Murray, published in 1838. as containing interesting accounts of fungi growing upon insects. The Tulasne brothers were probably among the first to study the para- sitism of these fungi. “They published descriptions of some of them in 1857? and of others in 1865.2 Among those described in 1865 was S‘phaer- ostilbe coccophila Tul., which is one of the species treated of in this thesis as sometimes parasitic on Aleyrodes citri. The work of Pasteur on the flacherie of the silkworm, marked a great advance in our knowledge of insect diseases. This disease was due to a species of bacterium. Pasteur’s work was taken up with the view of protecting the insect from parasitic growth, while most subsequent work has been carried on with the view of destroying insect pests by means of their parasites. A work of much scien- tific importance was that of Roland Thaxter,? “The Entomophthoraceae of the United States”, published in 1888. The genera which he studied attack flies, beetles, moths, caterpillars, grasshoppers, and plant lice. Since the institution of Experiment Stations in the United States, ex- periments have been made with several species of fungi, with a view of using them in combating insect pests. Up to this time the greatest degree of success has been attained in Florida, where the conditions of temperature and moisture are conducive to the spread of fungi. The use of fungi to combat insect pests has met with only limited success in the Northern States. A number of years ago the employment of a species of Sporotrichum for spreading disease among chinch-bugs received much attention. In 1895, ' Vegetable Wasps and Plant Worms, pp. 41-43, London, 1892. “Cooke, M. C. Vegetable Wasps and Plant Worms, pp. 5, 33, 41, 73 281. * Memoirs of the Boston Society of Natural History, Vol. IV, No. 6. 06, 12 183) and INTRODUCTION. 7 S. A. Forbest of the Illinois Experiment Station gave a detailed account of cultures and infection experiments carried on with this fungus. A few sentences from his discussion of the results are here quoted: The white muscadine will not spread among vigorous chinch-bugs in the field in very dry weather to an extent to give this disease any practical value as a means of promptly arresting serious chinch-bug injury under such conditions. cai It is most likely to catch in low spots, where the soil is kept somewhat moist by dense vegetation, a mat of fallen herbage, or the like. i If decidedly wet weather follows upon its introduction, even after an interval several weeks, it is likely to start up and take visible effect; but continuous rains, depressing the vital energies of the insect, seem commonly requisite to its efficient action. Some investigation has been carried on with a number of other ento- mogenous fungi grown in pure cultures. G. F. Atkinson’ and R. H. Pettit® studied cultures of Cordyceps, Isaria and Sperotrichum. R. H. Pettit in his bulletin issued in 1895 included a long bibliography of the literature on entomogenous fungi, to which any one interested in the history of this subject is referred. Imts9%, PE. Rolts,* im his bulletin “A: Diseas®of the San: Jose Scale?’ demonstrated that the fungus Sphaerostilbe coccophila could be used in a practical way in combating the San Jose scale in Florida. In 1906, a valu- able paper by J. Parkin,§ “Fungi Parasitic on Scale Insects,” gave a general review and the distribution of the fungus parasites of Coccidae and Aley- rodidae which had been described in all countries up to that time. He referred to a recent publication by Gueguen® in France, which is said to be an exhaustive work on the fungus parasites of man and animals. A recent contribution by Dop!" on a new fungus parasite in Martinique that has saved the cocoanut industry of that island is also briefly mentioned. In Florida, insects belonging to the orders Coccidae and Aleyrodicdae are very subject to attacks of fungi. In addition to the six fungus parasites Aleyrodes citri here treated of, there are two other fungi which are not found on this insect, although they are quite common on scale insects of Citrus. These are Ophionectria coccicola E. & E., and Myriangium duriaci Mont., both of which are illustrated in Bulletin 94 of the Florida Experi- ment Station. Webber also found on the wax scale Ceroplastes floridensis, the fungus Aschersonia turbinata; and he mentions finding on various in- ‘Experiments with the Muscadine Disease of the Chinch-bug, ete., [ll Agr. Exp. Sta., Bul. 38, 1895. * Artificial cultures of an Entomogenous Fungus. Bot. Gaz., Vol. XTX, pp. 129-145, 1894. "Studies in Artificial Cultures of Entomogenous Fungi. Cornell Univ. Agr. Exp. Sta. 3ul. 97, 1895. “A Fungus Disease of the-San Jose Scale. Fla. Agr. Exp. Sta. Bul. 41, 1897. *Annals of Roy. Bot. Gard. Peradeniya, Vol. 3, Part 1. *Guéguen, F. Les Champignons parasites de homme et des animaux, pp. 252, Paris, 1904. Bot. Centralbl., XCVI, p. 644. “Dop, P. Bull. Sci. France et Belgique, XX XIX, p. 135, 1905. Bot. Centralbl.,. XCIX, p. 505. 5 FUNGI PARASITIC UPON ALEYRODES CITRI. sects other Aschersonias, which, as far as we know, he has not identified. Prof. H. H. Hume sent to the author in 1996 a species of Aschersonia found on what appeared to be an Aleyrodes on the leaves of [lex Dahoon. It 1s quite probable that further observation will reveal a number of other species of fungi parasitic upon insects of these two orders in Florida and the ad- joining States. ALEYRODES CITRI. This insect, the larval and pupal stages of which are parasitized by the fungi to be discussed later, has been a serious pest of orange groves in Florida and the adjoining States for a number of vears. It had been ob- served by C. V. Riley in 1878 in the greenhouses at the United States De- partment of Agriculture at Washington. In 1885, Mr. Ashmead wrote an account of it for the “Florida Despatch”, in which he gave it the name of Aleyrodes citri. In 1895, Riley and Howard?! first described this species in “Insect Life”. In this publication it is reported as having been received from Mississippi, Louisiana, North Carolina and many points in Florida. Gainesville and Crescent City are places mentioned at which it had been studied by Jas. Voyle and H. G. Hubbard, before 1893. It is also stated that during the years 1892 and 1893 it had so multiplied in parts of Louisiana and Florida as to deserve immediate attention. It is of interest here to note that it was about this time, 1893, that Webber discovered the first fungus para- site of this insect. This insect is not a true fly, as the name might imply, but belongs to the Order Hemiptera, which also includes the plant lice and scale insects. The following summary of the life-history of Aleyrodes citri is from Bul- letin 88 of the Florida Agricultural Experiment Station, by E. W. Berger: There are three well-defined broods of the whitefly, with an interval of several days to several weeks between each brood, when few or none are seen on the wing. The first brood generally appears some time during March, April or May; the second during June, July or August; and the third during September and October. Larvae and pupae of the whitefly are to be found on the under surfaces of the leaves, and seldom elsewhere. The larvae are scale-like and closely appressed against the leaf. They vary in size from the very young, just visible to the unaided eye, to the fully matured larvae which measure about one-sixteenth of an inch in length. The larvae are white and translucent with a tinge of yellow, and almost invisible upon the leaf. The pupa (Fig. 2, No. 8) is the transformation stage from the larva to the adult winged fly. The pupae are readily visible as yellowish-white, plump; oval bodies with a dark reddish spot on the back. From the pupa emerges the adult winged fly. The little white cases, with a T-shaped split on the back, found on the under surface of a leaf, are the empty pupa cases from which the adults have emerged (Fig. 2, No. 10). The eggs (Fig. 1, Nos. 3 and 4) are just visible to the unaided eye as a fine dust upon the under surface of the leaves. An ordinary hand lens will show them as little egg-shaped bodies much resembling grains of wheat aie SS Vs " Riley, C: V.,:and Howard, L. O. Insect Life, U. S. D. A., Div. of Entomology, Vol. V, No. 4, p. 220, Washington, D. C., 1893. Fig. 1—ALEYRODES CITRI.* 3. Ege: No. 4, Egg-shell; No. 5, Claspers at tip of No. 1 and 2, Adult female: No. 3, abdomen of male; No. 6, Antenna ; ETIMES MISTAKEN FOR ALEYRODES CITRI. Nos. 9 and 10, Margin of larva; No. 11, Larva No. 7, Fore margin of front wing. INSECTS SOM No. 8, Larva of Aleyrodes floridensts ; of Lecanium hesperidum., * From Fla. Agr. Exp. Sta. Bul. 67, by H. A. Gossard. Fig. 2.—ALEyroprs crrri* ge, at different magnifications : e; No. 5, Larva, fourth stage; No. Nos. 1 and 2, Larva, first sta No. 3, Larva, second stage > No. 4, Larva, third stag 6, Margin of advanced larva; No. 7, Vasiform orifice of fourth stage; No. 8, Pupa; No. 9, Adult emerging from pupa-case; No. 10, Empty pupa-case. *From Fla, Agr. Exp. Sta. Bul. 67, by H. A. Gossard. INTRODUCTION. 9) Twenty thousand eggs have been estimated_on a large orange leaf. From observa- tions made in the laboratory, egg-laying begins when the female is from eighteen to thirty hours old; and from seventeen to twenty-five eggs are deposited. These eggs are generally all laid within twenty-four hours after the first egg has been laid. Her length of life has been estimated at from three days in warm weather to three weeks in cool weather, and the complete length of life cycle from egg to adult is from forty or fifty days in summer to six months in winter, ; The origin of the whitefly pest in Florida is only a matter of con- jecture. It is not definitely known whether it is a native species or was introduced from the East. A recent report that Aleyrodes citri has been discovered in Asia gives some weight to the latter view. H. A. Gossard, in Bulletin 67 of the Florida Experiment Station, ‘Phe Whitefly”, 1903, said with regard to its advent in Florida: The fly seems to have been first known in Florida throughout the region comprised in Volusia, Marion, Lake, Alachua, and Orange counties; from which, I have little doubt, it was transferred to Manatee county and to local centers along the northern borders of the State. It had therefore become widely distributed before it attracted any consid- erable attention. At the present time it is widely distributed in many parts of Florida, and is spreading slowly to parts not before infested, in spite of the work that is done by the growers to keep it out of the groves. Several investigations are being carried on at the present time by the Florida Experiment Station, and by the United States Department of Agri- culture in order to work out practical methods of controlling the pest. Spraying with insecticides, fumigation with hydrocyanic acid gas under tents, and infection with fungus parasites have all been used. Fumigation and fungus infection are the most promising remedies known at the present time. The use of the fungus parasites in destroying this insect will be briefly discussed later, when the various fungi are described. The most serious injury caused by the whitefly is the sooty mold that always follows the insect. This is a species of Meliola, a soot-colored fungus that lives in the honeydew secreted by the whitefly larvae. Since the larvae are found upon the under surfaces of the leaves, the honeydew collects upon the upper surfaces of the leaves below and furnishes a suita- ble medium for the growth of Meliola. The sooty mold spreads in a black layer over the surface. The fruit is also blackened, so that it must frequently be washed before it is shipped. The vitality of the tree is lowered, not only by the loss of the nourishment sucked out by the insects, but also by the shutting off of the sunlight from the surfaces of the leaves. An account of this fungus is given by Webber in Bulletin 13 of the Division of Vegetable Physiology and Pathology, Washington, D. C. 10 FUNGI PARASITIC UPON ALEYRODES CITRI. Il. ASCHERSONIA ALEYRODIS WEBBER. This species was first discovered by H. J. Webber in August, 1893, at Crescent City, in the grove of J. H. Harp. Mr. Webber!? published a pre- liminary notice of the entomogenous nature of this fungus in 1894, referring it to Aschersonia tahitensis Mont. In 1896, under the same name, he mentions it in the bulletin, “The Principal Diseases of Citrus Fruits in Florida’.1% Finding it after further study to be a distinct species, he de- scribed it in 1897 in his bulletin, “Sooty Mold of the Orange and its Treat- ment,” as Aschersonia aleyrodis,'* as follows: Aschersonia aleyrodis Webber. Stroma hypophyllous, depressed hemispherical, pinkish buff or cream colored, coriaceous, 1—2/%mm. in diameter; mycelial hypothallus grayish white, forming a thin membrane closely adhering to the leaf and extending about 1 mm. beyond the stroma; perithecia membranaceous, at first superficial, later becoming immersed, irregular, reniform or orbicular in mature specimens, and opening by small, round, or elliptical pores or slits; basidia crowded, filiform, slender, con- tinuous, 28—40 microns long, 0.94—1.5 in diameter; paraphyses abundant, slender, projecting beyond the basidia, 65-100 microns long, 34—1 micron in diameter; spor- ules fusiform, continuous, mucilaginous, hyaline, sometimes obscurely 3—4 guttulate, 9 4—14.1 microns long by 0.94—1.88 microns wide, very abundant and erumpent, form- ing conspicuous coral red or rufus masses. (Parasitic on Aleyrodes citri R. & H. infest- ing citrous leaves in Florida). HISTORY. Some species of Aschersonia have been reported to be conidial stages of the genus Hypocrella, an Ascomycete. Massee'” speaks of having shown that the ascigerous forms of species of Aschersonia were produced on fallen leaves on which the conidial stages had grown. Parkin!® also mentions this genus as the probable perfect stages of species of Aschersonia and refers to a species of Hypocrella (/7. Raciborskii) described by Zimmerman," with a conidial stage referable to Aschersonia. No ascigerous forms have as yet been discovered in connection with the Aschersonias in Florida. In 1905, F. S. Earle'® reported Aschersonia aleyrodis on Aleyrodes citri in Cuba. In 1906, J. Parkin’? reported finding an Aschersonia on sev- eral undetermined species of Aleyrodes in Ceylon, which closely resembled Aschersonia aleyrodis. We said, “Numerous forms of Aschersonia have been found in Ceylon on species of Aleyrodes and Lecanium”. In February, 1908, Cook and Horne2® reported Aschersonia aleyrodis on Aleyrodes citri and on Aleyrodes howardti, in Cuba. ™ Webber, H. J. Journal of Mycology, Vol. VI, No. 4, p. 363, 1894. % Webber, H. J. Div. of Veg. Pnys. & Path., Bul. 8, p. 27, Washington, D. C., 1896. 4* Webber, H. J. Div. of Veg. Phys. & Path., Bul. 13, p. 21, Washington, D, C., 1897. % Massee, G. Jour. Bot. Vol. 34, p. 151. ® Parkin, J. Ann. Roy. Bot. Gard. Peradeniya, Vol. II], Part I, pp. 29 and 35, 1906. “ Zimmerman. Centralb. fur Bakt., Abth. II, Vol. VII, p. 872. 'S Primer Informe Anual de la Estacion Central Agronomica de Cuba, 1904 and 1905, p. 169, 1906. Annals Roy. Bot. Gard. Peradeniya, Vol. Ill, Part 1, p. 36, 1906. *° Cook, M. T., and Horne, W. T. Cuban Exp. Sta. Bul. 9, p. 31, 1908. ASCHERSONIA ALEYRODIS. ial Previous to Webber’s publication,?! the entomogenous nature of the genus Aschersonia was not known, although up to that time there were 19 species of this genus described, as recorded in Saccardo’s “Sylloge Fun- gorum”. This species was therefore the first known parasite of Aleyrodes citri, and was probably the first fungus that had been reported on any species of Aleyrodes. In the course of his investigations on the sooty mold, Webber reported that he had found three other species of Aschersonia, parasitic on other insects in Florida; one of which was Aschersonia tur- binata on the Wax Scale (Ceroplastes floridensis Comst.). The others were not determined by him. In 1897, when he wrote his bulletin on sooty mold, Webber reported that Aschersonia aleyrodis was found in Florida at Crescent City, Bartow, Panasoffkee and Gainesville. He also stated that no sign of the fungus was apparent in groves infested with Adleyrodes citri at Ocala, Orlando, Evinston and Ormond. In the same bulletin, the de- velopment of the fungus, the probable method of spore dissemination, and the methods of introducing the fungus on the orange trees, are discussed at some length. The description of the development of the fungus in the next paragraph is taken with slight changes from this bulletin.?? The first indication of the effect of the fungus on the larva of the whitefly is the appearance of slightly opaque, yellowish spots unusually near the edge of the larva. In the early stages of infection the larva becomes noticeably swollen, and appears to secrete a greater abundance of honeydew than normally. As the fungus develops, the interior organs of the larva appear to contract away from the margin, leaving a narrow circle, which becomes filled with hyphae. Shortly after this the hyphae burst out around the edge, forming a dense marginal fringe. This may form all around the larva at about the same time, or develop at one portion of the margin sooner than the others. Death usually ensues, it is believed, before the hyphae burst out. Tne fungus does not spread over the leaf to any extent, but grows upward in a mass, gradually spreading over the larval scale. It is not uncommon to find the pycnidia, with their bright coral-red masses of sporules, formed in a circle around the edge of the larva while it is yet visible. As the Aschersonia develops, the hyphae spread over the larva forming a dense compact stroma, which ultimately entirely envelops the larva. The stroma in this stage is thin and disk-like, the fructification being usually borne in a circle near the edge. The hyphae, which make up the main mass of the stroma are from 3.5 to 7.5 micro-millimeters in diameter. Within the body of the insect and near the pycnidia they are somewhat smaller. METHODS OF INTRODUCTION. Two methods of introducing the fungus into groves infested with Aleyrodes citri were used by Webber with fair success. (1) Pinning fungus-bearing leaves into trees infested with Aleyrodes citrit, in such a way as to cause the fungus spores to come in contact with larvae not vet infected. (2) Planting small trees with fungus infected larvae in a grove, so that the fungus-bearing leaves came in contact with the leaves on which ~ Webber, H. J. Div. of Veg. Phys. & Path.. Bul. 13, p. 20, Washington, D. C., 1897. ~ Webber, H. J. Div. of Veg. Phys. & Path., Bul. 13, pp. 23-24, Washington, D. C., 1897 12 FUNGI PARASITIC UPON ALEYRODES: CITRI. it was desired to start the fungus. Further methods of introducing this Aschersonia by spraying the trees with water containing fungus spores, obtained either from previously infected larvae or from artificial cultures, have been recently carried on by E. W. Berger?® of the Florida Experi- ment Station. Webber?! had tried infecting larvae by spraying a mixture of conidia in water, but had failed to reproduce the fungus in this way. EW. Berger has found that to succeed with this method it is best to have a spray pump that contains no copper parts, and that has also not been previously used for spraying fungicides or insecticides. Fairly good infection of this fungus has been obtained by Berger, by the spore-spraying method, at St. Petersburg, Leesburg, New Smyrna, Gainesville and Lake City. The fact that infections may be made from cultures that have grown under artificial conditions in the laboratory for long periods of time, suggests the possi- bility of using these cultures in a practical way at the very beginning of the rainy season, when fresh fungus on leaves is hard to obtain. Consid- erable quantities of this fungus may be grown artificially on various media, as will be shown in the following pages. GERMINATION OF CONIDIA. Conidia of this fungus were germinated in hanging drop cultures of dis- tilled water, tap water, and various solutions of glucose. In all of these cultures the germination was very slow, scarcely ever beginning in less time than 20 hours. Germination in distilled water and tap water was very feeble, while that in solutions of glucose was much stronger, as is explained more fully under the germination tests for Aschersonia flavo-citrina. Trials were made at various times to germinate spores in hanging drop cultures from pustules that had dried in the atmosphere of the laboratory. The following is a record of these tests: Ve 1. On November 10, 1906. cultures were made from leaves collected on October 12, 1906, which had remained / in the laboratory 28 days. The tests were made in glucose, in distilled water, and in tap water. On December 11 (31 days) sporids formed in 5 per cent. glucose. The growths Fig. 3. in distilled water and in tap water had not proceeded far. ey Otte a 2. On January 5, 1997, cultures were made from leaves X 1000. collected October 12, 1906, which had remained in the laboratory for 85 days. The test was made in distilled water. No germina- tion took place. i Fla. Exp. Sta. Bul. 88, pp. 57-63, 1906. ~ Webber, H. J. Div. of Veg. Phys. & Path., Bul. 13, p. 26, Washington, D. C. ASCHERSONIA ALEYRODIS. 15 3. On April 18, 1907, cultures were made in tap water from leaves collected October 12, 1906, which had remained in the laboratory 189 days No germination took place. a 4. On April 18, 1907, cultures were made in tap SSS water from leaves collected on December 12, 1906, fig. 4 coniaium of Ascher- re ‘ : bs Fe STI5N8) oe T sonia aleyrodis after 6 days which had remained in the laboratory 128 days. No Hig hescat Giada Gi germination took place. tion at 25°C... x 1000, 5. On April 18, 1907, germination trials were made from a culture isolated December 7, 1996, which was transferred to potato on January 14, 1907, and had not entirely dried out. A few spores germinated. CULTURES. Pure cultures of Aschersonia aleyrodis were first obtained in January, 1907. On December 7, 1906, petri dishes of neutral 5 per cent. glucose agar were poured. These were made by introducing into the melted agar a platinum loop, that had been thrust several times into a test-tube containing spores from several stromata shaken up in sterile water. In the first dilu- tion, on January 5 (29 days), at a temperature of 15° to 25° C., minute fungus mycelia appeared, yellow in the center, with a fringe of delicate white hyphae projecting outward. On January 8 (32 days), the largest of these had turned red in color. They were raised, hemispherical, and had the upper surface dotted with little white lumps. Larger stromata were 2 to 4 mm. in diameter. On January 15 (39 days) the stromata were 5 to 7 mm. broad, with a wide fringe of straight hyphae projecting outward over the agar. The stroma by this time contained pyenidial cavities with spores ( (Plate I, Fig. 20) On April 10, 1907, a fungus was again isolated. Leaves were picked at Orlando, on April 6. Pustules were broken up in water in a watch-glass, and a dilution set of three petri dishes A, B and C, was poured with agar (1 per cent. normal acid to phenolphthalein), to which 5 per cent. glucose sugar had been added. Petri dish A was overrun with bacteria and quick- growing fungi. Petri dish B contained, on April 26 (16 days), about 50 centers of growth just beginning, and a few bacteria. Petri dish C, on April 26 (16 days), contained no visible growth. On May 11 (31 days), C contained a fine growth of 11 mycelia, which probably first showed a few days before. No further record was kept. On September 23, 1907, this fungus was isolated for the third time in petri dish cultures A, B and C. Four or five small pustules were shaken up in 7 cc. of water until it became milky in appearance. Five loopfuls were washed into A, ete. A was contaminated with other fungi, C developed one mycetum of A. aleyrodis, and one of another fungus. Petri dish B devel- oped a pure culture as follows:—On October 8 (15 days), one point of growth was just appearing. On October 18, there were four mycelia, five to six mm. in diameter, with one of reddish pycnidia; and seven others just starting. On October 28 (35 days), twenty very red pustules with abundant spores and light gray fringes of outgrowing hyphae had de- veloped. From these isolation tests, it appears that on 5-10 per cent. glucose agar in the laboratory, it requires from 30-40 days for the fungus to mature a pustule and produce pyenidia. This time corresponds somewhat closely to the time for the fungus to develop upon larvae of Aleyrodes citri, as 114 FUNGI PARASITIC UPON ALEYRODES CITRI. shown by the infection experiments of E. W. Berger. (See Bulletin 88, Florida Experiment Station, pp. 57, 58.) The fungus is extremely slow in developing in the petri dishes, thus increasing the liability to contamination with other fungi and bacteria. Its slow-growing habit demands therefore a strictly pure culture, since the rapidly growing fungi and bacteria will otherwise crowd it out completely. The many previous failures of the author and of others before him to grow this fungus in cultures, were probably due to the fact that the petri dishes were rejected too soon, or were allowed to dry out before the spores had time to form mycelia and stromata. This fungus was transferred from petri dish cultures to test-tubes of sweet potato (Plate I, Fig. 22), Irish potato, rice, white cornmeal (Plate I, Figs. 21, 23), and bread. On all of these media, the growth was similar in general appearance to the growth of Aschersonia flavo-citrina, except that the color of the stroma and spore- masses was red instead of yellow. The most luxuriant growth was on sweet potato plugs. The characteristic red color of the fungus stroma rarely ap- peared on Irish potatoes. This would seem to indicate that sugar was necessary for the proper development of both the red pigment of Ascher- sonia aleyrodis, and the yellow pigment of 4. flavo-citrina. The growth on sweet potato plugs is given here for comparison with the growth of Aschersonia flavo-citrina on this same medium. 1. On April 8, 1907, spores were transferred from cultures made on January 14, 1907. The spores were streaked onto the surface of the sweet potato plug with a platinum needle. On April 17, abundant growth all along the streak had begun. On April 26, a large raised red mass, 40 mm. long, had formed. 2. On April 8, spores were transferred as in No, 1. On April 17, very abundant growth had started, and on April 26, a very large red mass had formed. 3. On April 8, spores were transferred as in No. 1. On April 17, good growth with thickened points had started. On April 26, a very large mass of red growth had formed. 4; On April 8; spores* were: transterned! as Nop @neerpnilening cream-colored to orange, mealy appearance was evident, spreading to each side of the streak. On April 26, an abundant growth, red in color, had formed. EXPERIMENTS IN GROWING ASCHERSONIA ALEYRODIS IN LARGE QUANTITIES. In April, 1907, experiments were begun in order to grow large quantities of fungus for infection of Aleyrodes citri. Ten large moist chambers, nine wide-mouthed bottles of 590 cc. capacity, and four petri dishes five inches in diameter, were prepared with sweet potato medium. The potatoes were washed, peeled, washed again and put through a meat chopper. This ground-up mass was then washed in running water to get out fine particles, and the moist medium was sterilized in the autoclave at 110° C. for about 20 minutes. After sterilization, the medium appeared well cooked. On April 5, these were inoculated, in the transfer closet, by spraying the surface of the medium with a hand atomizer with a mixture of conidia in ASCHERSONIA ALEYRODIS. 15 sterile water. The conidia were obtained from an old culture of the fungus grown on sweet potato. All of the cultures, except two large petri dishes, finally became contaminated with a growth of bacteria. This was probably due to insufficient sterilization of the interiors of the large masses of medium ‘n the moist chambers and in the 500 cc. bottles. The fungus in the two petri dishes which were successful, appeared in 15 days as a creamy white, teit-like growth over the surface of the medium, with no red color. Very little red color appeared later, and no large spore-masses developed. It seemed that the spores had been sown too thickly over the surface to develop the characteristic pustules with pycnidial cavities. This experiment was practically a failure. On June 12, 1907, five bottles of ground-up sweet potato, and one bottle of bread, which had been sterilized in an autoclave for about half an hour at 120° C., were inoculated by streaking the surface with a large platinum loop from cultures previously made on sweet potatoes. Three of these were successful, two on sweet potato, and one on bread. The notes on these are as follows: 1. On June 12, 1907, a culture on bread was made from a culture on sweet potato plug, which had been transferred three times from an isolation culture in petri dish poured December 7, 1906, and described above. Transfers had been made on January 14, 1907, April 10, 1907, and June 3, 1997. On June 19, the fungus was growing well at one point. On July 1, a large raised mass % inch in diameter was formed. On July 20, a large area 1 inch in diameter, and red in the interior, with abund- ant spores, had grown. 2. On June 12, 1907, a culture on sweet potato was made from another culture with same history as above. On June 19, the fungus had started at seven points. On July 1, masses 1-3 inch in diameter had formed on one side of the bottle. 3. On June 12, 1907, a culture on sweet potato was made from a sweet potato plug, which had been transferred once from a petri dish culture of April 10, 1907, being transferred on June 3, 1907. On June 19, the fungus was just starting at three points. On July 1, raised areas one inch in diameter had formed on one side. On July 20, a growth 1% inch in diam- eter had formed. On June 19, six bottles of sweet potato and one of bread were inoculated from sweet potato test-tube cultures which had been transferred twice from an isolation culture made not later than April 10, 1907. Four bottles de- veloped pure cultures. 1. On June 19, 1997, the surface of a bottle of sweet potato medium was streaked with a small needle from a culture of June 3, 1907. On July 1, three or four areas of growth had appeared. On July 20, a good white growth had formed all around the base of the potato plug. 2. On June 19, 1907, sweet potato medium was streaked as in No. 1, from a culture made June 3, 1907. On July 1, a good growth had formed on the surface, white and lumpy in appearance. On July 20, the growth had formed all over the surface of potato, and spores had grown in the pycnidia. On August 12, spores were very abundant. 3. On June 19, 1907, sweet potato medium was inoculated by shaking up conidia in a test-tube of water and pouring it over the plug. On July 1. very small areas on side of glass appeared. On August 12, areas of large size had grown, but no conidia could be found. 16 FUNGI PARASITIC UPON ALEYRODES CITRI. {. On June 19, 1907, bread medium was inoculated as the sweet potato in No. 3, with conidia from a culture made on June 3, 1907. The old potato plug from the same culture was also dropped in. On July 1, a good growth out from old plug had started. On July 20, growth over nearly entire surface, reddish in patches, had formed. On August 12, no conidia could ke found. INFECIIGN OF ALEYRODES CITRI FROM CULTURES: In two localities in the State, this fungus was started on larvae of Aleyrodes citri, from cultures which had grown for some time on culture media in the laboratory. This infection work was done by E. W. Berger at Gainesville and St. Petersburg, from cultures grown by the author. The following records are taken from E. W. Berger’s field notes: 1. August 10, 1907. Gainesville. From culture on sweet potato made June 23, having been isolated not later than April 10, 1907. Culture mixed up in water and sprayed with hand sprayer on under surface of leaves on lower branches of an orange tree. October 6, no fungus found. On November 16, three pustules of fungus found. On December 31, sprinkling of pustules evident. April 3, 1908, quite a sprinkling of fungus pustules evident. 2. August 10, 1907. Gainesville, Florida. From old cultures in three test-tubes. Age of cultures unknown. No start by April 3, 1908. 3. August 15, 1907. St. Petersburg, Florida. From culture made June 19, on bread in large bottles and transferred twice before from cultures isolated not later than April 10. The culture was washed to fine pulp in water and strained. One and a half to two quarts of the liquid was used. Sprayed on the under side of leaves with a compressed-air sprayer. On October 23, quite a sprinkling of fungus was found. Some twigs had several leaves well covered with pustules, mainly on the newest growth. On December 10, about the same condition. On February 8, 1908, an abund- ance of fungus was found on northwest side of tree, and fresh pustules were appearing. 4. August 15, 1907. St. Petersburg, Florida. From culture on sweet potato, made June 19, 1907. Culture washed to fine pulp and strained. Two quarts of solu- tion were sprayed on with compressed-air hand sprayer. On October 23, a good sprinkling of fungus was found with some leaves well covered. Best catch was on west side, mainly on newer growth. On December 10, 1907, pustules more mature, but apparently not spreading. On February 8, 1908, an abundant catch of fungus was evident. 5 5. August 15, 1907. St. Petersburg, Florida. From a mixture of two cultures, one of Aschersonia aleyrodis made June 19 on potato plug and transferred twice before; the other of Aschersonia flavo-citrina made May 23, on sweet potatoes in a bottle, and transferred twice before. Cultures mixed, washed and strained, making one gallon of the solution. On October 23, fair sprinkling of the fungus, probably only the red, mainly on newer growth. On December 10, same, but pustules more matured. On February 8, 1908, all red pustules, no yellow present. 6. August 14, 1907. St. Petersburg, Florida. From culture made June 19, 1907, and transferred twice before. No start by February 8, 1908. 7. August 14, 1907. St. Petersburg, Florida. From culture made April 8, 1906, which had been dried for two months. The fungus had been transferred twice before. Isolated from petri dish culture made December 7, 1906. No start of fungus by Feb- tuary -8, 1908. ASCHERSONIA FLAVO-CITRINA. iN DISTRIBUTION OF ASCHERSONIA ALEYRODIS IN 1908. In Florida it has been reported from or seen at the following places, occurring only on clleyrodes citri: Alva, Apopka, Bartow, Bradentown, Buckingham, Citra, Fort Myers, Gainesville, Glen St. Mary, Jacksonville, Lake City, Leesburg, Manatee, McIntosh, New Smyrna, Oneco, Orlando, Oviedo, Palmetto, Sarasota, St. Petersburg, St. Augustine. Outside of Florida it was reported by Cook and Horne from Cuba on Aleyrodes citri R. & H., and Aleyrodes howardii Quaintance; from Java by Kirkaldy & Kotinsky, doubtfully upon Aleyrodes longicornis Zehntner ; from Brazil by the same authority, doubtfully upon also reported having received it from eal Baxp.- Sta. Bull 56" pp, 270-280: “ N. J. Exp. Sta. Rept. 18, pp. 470-479, 1897. Rept. 19, pp. 445-446, 1898. Rept. 24, p. 567, 1903. Canada Exp. Farm Rept., p. 119, 1897. * Ohio Exp. Sta. Bul. 103, p. 198, 1898. * Fla. Exp. Sta. Rept., p. 27, 1905. MICROCERA. 29 Orlando. In 1906, E. W. Berger found it on a few whitefly larvae at Leesburg, Florida. The effect of this parasite upon Aleyrodes citri seems to be of little practical value. It has only rarely been observed attacking this insect, and then does not occur in quantity, as do the other fungi before spoken of. It is not uncommon to find a large amount of this fungus upon Mytilaspis citricola in trees that are at the same time infested with larvae of Aleyredes citri on which no fungus can be found. LIS! OF INSECTS PARASITIZED. A list of insects reported to be attacked by this fungus is here given, together with the authority for the report and the localities in which they were found parasitized: NAME oF INSECT. Locality. AUTHORITY. AUC TADOIAS: (Ciltiad. IRs Sc lela hoes sobaad no oto oe Ikoriah, "Sganeosceecee H. A. Gossard. TAG MICHOUDS CHEMO IX biineyin saos oda eooOae oT IMlOmGl Jon ccccodaooc i. W. Berger. Aspidiotus articulatus Morgan ............ Jaina Cane ieee tL Dp. AL Cockerelll: Aspidiotus articulatus Morgan............. Wiest iniGa ee ae J. Parkin. Aspidiotus articulatus Morgan ............ WWiestalimdtestaaciassnee J. Parkin. Asprdiotus auranin Mask ..............+5 ANGSUUIE, “oaacaboo0o¢ D. McAlpine. Aspidiotus auranin Mask ................ INeataltect cae Fuller. Aspidiotus auranin: Mask sc. 2 so. a. 205%: Ceylomnersc ..552. eee J. Parkin. (Chrysomphalus) aurantii Mask.......... ransvaaliesn. Sadar C. W. Howard. ALS OOS. Peus (CONN: sésccacaenopoeeces- slonidaeere eee (Chrysomphalus aonidum) JVinn.......... “Dans eee ene C. W. Howard. Aspidiotus hederae (Nall) ....5...5:.-225-. [Mlorancky Sos gomocgote. E. W. Berger. A spidioiusooscurus Comst. ..¢..2......--. Hlonidamecseprec cite P. H. Rolfs. Aspidiotus perniciosus Comst. ............ Blond ages ame: Pe EieRolits: Aspidiotus perniciosus Comst. ...........-. [apatite cree ere S. I. Kuwana. Ghitanas piss cliva (COmMStS Gece ss ecw classes Cubase eee eee Cook and Horne. Diaspis pentagona Tare. 2.200335 sacaeneees: lapankos each eae S. I. Kuwana. Fiorina horimiaeg Vate: ..s.b..0si0aaagers Nattriiitisy acacnm roe Je Barkin USA NVOSUS IMOALOS: Gas wooads achadseauades Wiestalinvdiesm amen J. Parkin. MMOS DES CHMAICOUGS IEE, yo dob acddc coo n5 oe Gevlon ters a sremeese J. Parkin. Miyinlaspis. cttricola: Pack, 224... sce ecse- a3 Ctiba eens Geaae one Bes) Mane: Miitl as pusvcitiicolan Rack... s ing and forma- i tion of one- and made up of a compact mass of lunate two-celled coni- dia, X 1000. spores (Fig. 17). These are 3- to {A § 5-septate, and 28 to 40 microns long, by 3.5 to 5 microns thick, in fresh specimens. When the larvae are placed in distilled water on a microscope slide, é c : i Fig. 17. Conidia of Microcera the fungus spores are seen to float apart and spread ~ from larvae dried on leaves : of Citrus, X 450. out in the water. CULTURES. Culture of this Microcera were grown much more easily and quickly than those of any of the previously described fungi. This fungus grew rapidly on nearly all kinds of media which were tried. On September 14, 1907, the day after the fungus had been examined and recognized as a new parasite on Aley- rodes citri, three sets of petri dish cultures of three each, A, B, and C, were prepared according to the usual method for isolation. The first set was made by touching an in- fected larva with a moist platinum needle, and ‘washing the needle off in test-tube A. B received three loops from Fig. 18. Conidia from test-tube mul. $A, and C three loops from B. In three days on petri dish ture of Microcera A two mycelia and a number of bacterial colonies were ea haddried evident. In nine days, the fungus had overrun almost the entire dish, in spite of the bacteria present, and was pro- ducing an abundance of conidia. B and C developed no fungus. MICROCERA. 31 The second set was inoculated with spores from a test-tube in which an infected larva had been shaken up in water. In both A and B, a good growth of fungus appeared. The fungus just showed after 24 hours. In A, in three days, there were about 50 mycelia. In B, in three days, the mycelia, three in number, had become 19 to 12 mm. in diameter, loosely tufted, with numerous conidia on the upwardly projecting, irregularly branching hyphae. In nine days, the growth had covered the entire surface of the medium. The third set was inoculated from a test-tube containing a little sterile water, in which two infected larvae had been placed. Only the first petri dish A developed a growth of Microcera, which grew as described for the second set. The fungus in all cases was of a pure white color. It grew in loose tufts, with upwardly growing, very delicate hyphae, forming a loose, fluffy mass, which soon collapsed when the cover of the petri dish was removed. A microscopic examination of this growth showed that it was made up of irregularly branching hyphae bearing conidia. All intermediate shapes of spores from the oval one-celled conidium, to the septate lunate conidium, could be found in the same culture. (Figs. 16, 17, 18). It may be remarked in this connection, that in the cultures of Sphaerostilbe coccophila made by P. H. Rolfs in 1897, the conidial stage of which has been referred to Microcera, these one- and two-celled conidia appeared, and are figured by him in Bulletin 41 of the Florida Experiment Station, Plate I]. Judging from the growth of Aficrocera sp. in cultures, it would probably fit into the genus Fusarium, but since the distinction be- tween Microcera and Fusarium is rather vague, we prefer to hold to the name Microcera until the perfect stage is worked out. Perithecia of this fungus appear to be developing at the present time on culture media. On September 18, two test-tubes of standard agar, one of Irish potato, and one of rice, were inoculated by drawing a moist needle over the top of culture B of the second set poured on September 14. On agar tubes there seemed to be some evidence of growth in three or four hours. On September 21 (3 days), tufts of white mycelium were formed over the entire surface. On November 20, the agar had begun to shrink away from the sides of the tube, and the fungus had grown down over the sides of the medium. On Irish potato, September 28, almost the entire surface was covered with a snowy white growth of fungus. On rice in a 50 cc. flask, by November 11 (54 days) the entire surface was covered with growth, and the spaces between the rice grains were packed with a fungus mycelium. The mycelium was very thick, matted, and pink on the sides near the glass (Plate VI, Figs. 39 and 40). On September 25, a test-tube and a flask of rice, and two tubes of bread, were inoculated from the same culture as before. On rice, September 28 (3 days), a delicate growth 10 mm. high was formed in the test-tube. The rice had turned pinkish from the top to 34 inch down on the sides. In the flask almost the entire surface was covered, and was pinkish at the base on the sides of the rice. By October 18 (23 days) the fungus had grown through all the available spaces in the medium, forming a pinkish matted SS) Cas) FUNGI PARASITIC UPON ALEYRODES CITRI. growth. On November 11, numerous conidia were present in pink masses on the sides of the rice. On the bread, on September 28 (5 days), a delicate white growth was formed over the upper surface. On October 10 (16 days), “the growth had taken up every available space in *he pores of the bread, giving it a pinkish matted appearance. On October 11 the following cultures were made by transferring spores from the bread cultures of September 25, which had been transferred once before. Three tubes of agar, one of sweet potato, one of Irish potato, one of rice in a 50 ce. flask, and one of bread were used. Notes were taken on October 19 only. In the three agar tubes, which reacted 1.0, 1.5 and 2.0 respectively to phenolphthalein, the growth was about one inch high with abundance of conidia. ‘There was no noticeable difference in the ‘erowth. On sweet potatoes, a pure white, delicate growth appeared; on Irish po- tatoes, a very abundant growth; on rice, an abundant growth with a pink- ish color on the surface, and thick mycelium between the rice grains. INFECTION OF ALEYRODES CIERI. On September 19, 1907, infection experiments were made on healthy whitefly larvae from cultures of this fungus. The larvae were on the leaves of a privet hedge (Ligustrum ovalifolium) in Gainesville. The following is taken from notes made at the time of the experiments: Healthy larvae were very abundant on the privet leaves. The weather was damp after a rain. Inoculations were made from 3 to 5 P. M. No. 1. Inoculation was made from culture of September 14; conidia were penciled on the under side of the leaves on one branch with a moist camel’s-hair brush; a piece of cheese cloth was tied around the inoculated branch. On September 21 no conidia were found; the cheese cloth was removed. On September 28, no conidia were found. On October 5, abund- ant conidia of Microcera were present. On October 25, about 50 per cent. of the larvae were dead. No. 2. Inoculation was made from same culture, penciled on as in No. 1, but not covered with cheese cloth. On September 28, no spores were found. On October 1, spores of Microcera were present. On October 5, pink spore-masses were developed on the edges of larvae. By October 25, about 59 per cent. of larvae were dead. No. 3. Conidia were penciled on as above, and not covered with cheese cloth. On September 21, no spores were found. On September 28, no spores were found. On October 1, Microcera spores were present. On October 5, pink spore masses were present on the edges of the larvae. On October 25, about 50 per cent. of the larvae were dead. No. 4. Inoculation was made from larvae on citrus leaves from Mana- tee. No cheese cloth was tied around. On September 21, larvae seemed to be attacked by a small fungus, which looked like the Microcera of the cultures. The conidia were one- and two-celled. On September 28, abund- ant spores of Microcera on dead larvae were found, and live larvae with filaments of fungus within. About 60 per cent. estimated dead. On Octo- ber 5, pink conidial masses were evident on edges of larvae. No. 5. A branch as a check was not inoculated, but tied up with cheese cloth. On September 21, no conidia of Microcera were to be found, On September 28, no conidia of Microcera to be found. Oo MICROCERA. Se No. 6. A branch near No. 5 was neither inoculated, nor tied with cheese cloth. On September 21, no spores of Microcera were to be found. On September 28, no spores of Microcera were found. No. %. A branch above No. 4 was neither inoculated, nor tied with cheese cloth. When examined on September 28, no Microcera could be found. During the first two weeks after these infection experiments were made there were frequent rains, and the weather was quite moist. This was fol- lowed by two weeks of drier weather during which the fungus apparently ceased to grow. These inoculation experiments show that under favorable climatic conditions like those under which they were carried on, the larvae of Aleyrodes citri may readily be infected either directly from previously infected larvae, or from pure cultures GERMINATION OF CONIDIA. The conidia of Microcera germinated quite readily in water. On Octo- ber 3, a hanging drop culture was made with conidia from a potato culture. In 24 hours, one of the cells of the conidia, usually the end cell, sent out hyphal tubes to a distance of one to four times the length of the conidia. On the end of a number of these were seen small oval sporids (Fig. 19). In 48 hours the hyphae were 6 to 7 times the length of the conidia, some of them branched as in Fig. 19, and many sporids had formed. In six days the branching hyphae were prominent, with many sporids. The segments of the conidia had become swollen, thus causing constrictions Fig. 19. Conidium of Microcera germinating at the septa. and forming sporids. (a) Conidium, () hyphal tube, (¢) sporid, X 450. VARIATION IN SIZE OF CONIDIA. The measurements of conidia at various times and under various con- ditions indicated a considerable variation in size. The greatest variation was in the length. As has been said, the conidia varied from oval one- celled spores to long lunate spores. Measurements of lunate spores on larvae were as follows On September 23, the first specimen from Sutherland after drying bore conidia measuring 28—40 by 3.5—5 microns. On September 26, the second lot of specimens from Sutherland, while still fresh, contained conidia meas- uring 36—45 X3.5—4.5 microns. On October 5, privet leaves from inocu- lation experiment No. 4, at Gainesville, while still fresh, bore conidia meas- uring 31—52*3.5—4.5 Measurements of lunate spores in cultures were as follows On September 17, conidia from cultures made September 14 measured 21—32 *3.5—4.5 microns. On November 21,*conidia from culture on potato, measured 12 to 30 microns long; two-celled conidia were 12 microns, the others longer. On February 2, 1908, from cultures 101 days old, made October 26, 1907, on white cornmeal cultures not dried out; conidia in pink 34 FUNGI PARASITIC UPON ALEYRODES CITRI. cushion-shaped masses, 5-septate, 40—60 microns long; most of them 40 microns, few 60 microns. On June 2, 1998, from culture on bread made September 25, 1906, dried out; conidia 15—30<3—4.5 microns. DISTRIBUTION OF MICROCERA SP. IN FLORIDA. Sutherlandien nesclsorrien veneers eee September 13, 1907. Wierinaltic Cr ee apenas erence tons ot ae ee ae September 18, 1907. Gainesvulll hype eet ere ok ee ee eae September 21, 1907. (Introduced. ) IE ESDULO aos Eee a Re Se oe eee October Te OO Orlandone ee eee een ee ee ae eee November 25, 1907. [att Oa ene ee een al «cen ND eee ie eee November 1907. oTbttitaswallteses4tas civecsen eencrase ee aed eae ey ee December “35/1907: SHAG ni lea ENGI Olr sm aurenmind Gin mightier, aie Gina oe March, 1908. VIL Ae BROWN FUNGUS OF Ab YRODESu@ liar In March, 1896, H. J. Webber°® discovered this fungus on whitefly larvae in the grove of J. H. Viser, Manatee, Florida. During the summer of that year the fungus spread rapidly through the Viser grove, and was observed to be a very effective parasite of Aleyrodes citri. As no fructifica- tion of any kind has been found in connection with this fungus, it has not been classified. It has been known since its discovery as the “Brown Fungus” of the whitefly (Plate VII, Fig. 42). DESCRIPTION. Webber’* gave a general description of this fungus in Bulletin 13 of the Division of Vegetable Physiology and Pathology, as follows: The mature stroma is compressed hemispherical, frequently having a slight de- pression in the apex over the center of the insect, where the hyphae come together as they spread from the edges of the scale in their development. The size varies greatly, according to the stage of development of the insect attacked. In very young larvae it is from % to % a millimeter in diameter. In mature larvae and pupae it frequently reaches 2 millimeters in diameter. The thickness, or height, also varies in like manner, specimens on mature larvae or pupae being usually from 175 to 260 microns, while those on young larvae are much thinner. * * * The stroma is commonly seal brown, with a shade of chestnut, but becomes slightly darker with age. * * * The hyphae, which make up the body of the stroma, are light brown, very tortuous, and but slightly branched. ‘Those in the body of the insect are of similar character, but a much darker brown. From the base of the stroma a ground mycelium, or hypothallus, spreads out in all directions on the surface of the leaf, forming a compact membrane near the stroma, but becoming gradually dispersed into separate filaments. * * * The hyphae of the hypothallus are colorless, sparingly branched, mostly continuous, having only an occasional septum, and are from 5 to 7 microns in diameter. In some places in the hypothallus, where the hyphae are apparently somewhat massed and knotted, they become light brown, similar in color to the isolated hyphae of the stroma, SE Div. of Veg. Phys. & Path., Washington, D. C., Bul. 13, p. 27, 1897. “Tbid. pp. 28-30. t THE BROWN FUNGUS. 3 e BROWN FUNGUS OF PARKIN. J. Parkin®’ in writing of the Ceylon forms of fungi parasitic on Aley- rodes, mentions having found on three different kinds of leaves a brown sterile fungus, which he thinks is similar to the one described by Webber on Aleyrodes citri. He also states that these brown pustules were in many cases closely associated with Aschersonia aleyrodis of Webber, and suggests the possibility of one being a form of the other. In regard to this point he writes : Intermingled with the brightly colored Aschersonia stromata on the leaf of Flemingia strobilifera were other brown ones. Many of these latter were evidently old or arrested Aschersonia stromata, as sections of them revealed closed pycnidia. Others again were flatter, more nearly resembling Webber’s brown fungus, thus sug- gesting the possibility of all these sterile pustules being really connected with Ascher- sonia. The two fungi often appear in association on the same scale and even on the same leaf. Webber mentions that 4. aleyrodis was present on those orange bushes containing also the “brown mealy wing fungus”. In the Ceylon specimen on Meme- cylon the two were intimately associated. Atmospheric conditions such as dryness may also influence the development of the Aschersonia as to induce it to assume a sterile resting form. This, when conditions are again favorable, might send out in- fecting hyphae over the leaf surface. Webber’s account of how this brown fungus develops and spreads hardly favors such a view. However, its close association with Aschersonia is a point to be kept in mind. By cultures perhaps this sterile form might be induced to form some fructifications, and so a clue to its nature and relationship might be obtained. The cultures of Aschersonia aleyrodis and Aschersonia flavo-citrina made by the author on various media and at different times of year with varying amounts of water, never showed any tendency to develop the brown sterile form of the Brown fungus. In Florida there seems to be no evidence to indicate any connection between this sterile Brown fungus and the Ascher- sonias parasitic upon Aleyrodes citri. METHODS OF INTRODUCTION. Webber, in. the bulletin previously referred to, describes in some detail the method of introducing this fungus into trees infested with Aleyrodes citri by pinning in leaves, or by planting young fungus-bearing trees in such a way that their leaves would come in contact with the larvae-bearing leaves to be infected with fungus. E. W. Berger®® has recently produced some infection by grinding up the brown stromata, stirring with water, and spraying this water upon infested leaves. A number of attempts have been made by the writer to grow cultures of this fungus in the laboratory, but so far he has been unsuccessful. In one case where stromata of the brown fungus were placed close to a drop of agar in a hanging drop culture, short tortuous hyphae were seen to grow * Annals Roy. Bot. Gard. Peradeniya, Vol. III, Part I, p. 52, 1906. “Fla, Exp. Sta. Bul 88, "p.-64, 1906: 36 FUNGI PARASITIC UPON ALEYRODES CITRI. out from the edge. This is the only growth that has so far been observed under artificial conditions. DISTRIBUTION OF THE BROWN FUNGUS. Florida.—Alva, Bartow, Buckingham, Bradentown, Fort Myers, Largo, Leesburg, Manatee, Oneco, Orlando, Palmetto, St. Augustine and St. Petersburg, on Aleyrodes citri. Ceylon, as reported by J. Parkin, on various species of Aleyrodes. SURPELEMENTARY NOTES. 1. Since the above has been written, what appear to be the spores of the Brown fungus of Aleyrodes citri have been discovered. ‘These spores are germinating in hanging drop cultures of sugar solutions, and are pro- ducing hyphae that seem to be identical with those of the Brown fungus. Further study is needed to prove the relationship of these spores to the Brown fungus. 2. A species of Sporotrichum has been discovered upon the adult and larva of Aleyrodes citri. ‘This fungus seems to be responsible, during damp weather, for the premature death of great numbers of adults. Cultures and inoculation experiments are being carried on, the results of which will be published later. 3. Since the writing of this thesis it has been shown by Dr. E. W. Berger, Entomologist of the Florida Experiment Station, that the insects hitherto designated as Aleyrodes citrt comprise two distinct species of Aleyrodes; one with smooth eggs and clear wings, and the other with rough eggs covered with a delicate net of five- and six-sided meshes, and wings with a smoky-colored area at the end of each fore wing. Specific differences have also been observed in the first and fourth stage larvae. (See Press Bulletin.97, Fla. Agri. Exp. Sta., and Proc. Fla. Sta. Hort. Soc. p: 86, 1908.) Dr. Berger’s observations and also those of the writer seem to show that these two species of Aleyrodes are differently attacked by the Aschersonias (A. aleyrodis and A, flavo-citrina), and also by the Brown fungus and Microcera sp. Aschersonia flavo-citrina attacks readily only the smoky- winged Aleyrodes, but will attack the clear-winged species. Aschersonia aleyrodis and the Brown fungus attack both species of Aleyrodes in an equal degree, but the greater number of the specimens so far observed have been found upon the clear-winged species. The Microcera has been found on both species of Aleyrodes, although it is more effective upon the smoky- winged species. The infection experiments described in the foregoing pages with cultures of Microcera sp. (page 32) and Verticilliwm heterocladum (page 24) were made upon the clear-winged species. The infection ex- periments also made by E. W. Berger at St. Petersburg and Gainesville (page 16) were also upon the clear-winged Aleyrodes. October 1, 1908. ~2 Oo SUMMARY. SUMMARY. 1. Entomogenous species of fungi representing many different genera have been described in the past hundred or more years. 2. These have not, until recent times, been studied from an economic standpoint. The greatest success in the use of fungi to combat insect pests seems to have been attained in Florida, where proper conditions of temperature and moisture are present. 3. Aleyrodes citri R. & H., known since 1885 as a pest to citrus trees in Florida, has spread to many citrus districts since that time, doing much damage chiefly by creating conditions favorable to the growth of Meliola. 4. A study of the fungi parasitic upon Aleyrodes citri shows that there are at least six species, five of which have been grown upon culture media in the laboratory. 5. Aschersonia aleyrodis Webber is the most widely distributed fungus parasite of Aleyrodes citri. It is easily isolated and grown in pure cultures in 5 to 10 per cent. glucose agar medium, maturing a stroma in 30 to 40 days. 6. Healthy larvae of Aleyrodes citri may be infected from cultures of this fungus by spraying a mixture of conidia in water on trees infested with Aleyrodes citri. 7. Aschersonia flavo-citrina P. Henn., which was recently found in eastern Florida, is also an important parasite of Aleyrodes citri. Its growth on culture media is the same as that of 4. aleyrodis. 8. Conidia of both of the Aschersonias germinated best in a 5 to 10 per cent. solution of glucose in water. Percentages of sugar above or below this retarded germination. Conidia from stromata dried in the laboratory for more than 28 days failed to germinate. 9. Verticillium heterocladum Penz. has been recently shown to occur parasitically upon Aleyrodes citri. It has also been observed on a number of other insects. Cultures and inoculation experiments show that this fungus is distinct from the “Brown fungus”, which it somewhat resembles in general appearance, and with which it is frequently found associated. 10. The growth of this fungus in cultures is much more rapid than that of the two species of Aschersonia described. 11. Sphaerostilbe coccophila, known since 1848, is world-wide in dis- tribution, and has been reported on no less than fifteen species of scale insects, in addition to being found on Aleyrodes citri. 12. Sphaerostilbe coccophila has been used in Florida as an effective parasite in controlling the San Jose scale and other scale insects. In more northern States it has not proved to be effective. It is possibly a weak parasite of Aleyrodes citri. 13. AMicrocera sp., recently discovered, has been found in a number of places in Florida attacking larvae of Aleyrodes citri. Abundant cultures of 38 FUNGI PARASITIC UPON ALEYRODES CITRI. this fungus may be grown in a few days, and larvae of Aleyrodes citri may be infected from these cultures. Conidia of this fungus vary greatly in size under different conditions of growth. 14. The Brown fungus, known in Florida since 1896, has never been observed to produce spores and is therefore unclassified. Its growth and development on Aleyrodes citrt were described by Webber. All attempts to grow this fungus in pure cultures have failed. (See, however, Supplement- ary Note 1.) BIBLIOGRAPHY: The literature referred to in this bibliography is grouped under seven heads, corre- sponding to the seven divisions under which the subject is discussed. The references in each division are arranged in chronological order. All but three of the papers have been seen by the author. These three are designated by an (*) asterisk. GENERAL. LITERATURE. (88) Forbes, S. A. On our present knowledge concerning Insect Diseases. Psyche, Vol. V, pp. 3-12, 1888-90. (Bibliography, pp. 15-22.) (88) Thaxter, Roland. The Entomophthoraceae of the United States. Memoirs of the Boston Soc. of Nat. History, Vol. IV, No. 6, 1888. (With bibliography. ) (88) Lugger, Otto. Fungi Which Kill Insects. Univ. of Minn. Ann. Rept. Agr., pp. 380-392, 1888. (92) Cooke, M. C. Vegetable Wasps and Plant Worms, London, 1892. (93) Riley, C. V. and Howard, lL. O. Insect Life, Div. of Ento., Wash, DiC, Wolk Ve Nol4) px 220; 1893: (95) Pettit, R. H. Studies in Artificial Cultures of Entomogenous Fungi. Cor- nell Univ. Agr. Exp. Sta. Bul. 97, 1895 (with bibliography). (95) Forbes, S. A. Experiments With the Muscadine Disease of the Chinch- bug, ete, Till, Agr Exp: Sta: Bull 38, 1895: (97) Rolts, P. H. A Disease of the San Jose Scale. Fla. Agr. Exp. Sta, Bul) 41, 1897. (98) Forbes, -“S: Az Tl Aer Exp: Sta, Bull 56, pp» 27022804898: (06) Parkin, J. Fungi Parasitic Upon Scale Insects (Coccidae and Aleyrodidae), etc. Ann. Roy. Bot. Gardens Peradeniya, Vol. III, Part I. (With bibliography. ) ASCHERSONIA ALEYRODIS WEBBER. (94) Webber, H. J. Preliminary Notice of a Fungus Parasite on Aleyrodes citri. Journ. of Mycol., Vol. VII, No. 4, p. 363, 1894. C96) Webber, H- J. Proc Pla. State Hort. Soc, p: 73, 1896: (96) Webber, H. J. The Principal Diseases of Citrus Fruits in Florida. Div. of Veg. Phys. and Path., Bul. 8, Washington, D. C., p. 27, 1896. (97) Webber, H. J. Sooty Mold of the Orange. Div. of Veg. Phys. and Path., Bul. 13, p. 20, Washington, D. C., 1897. (99) Saccardo, P. A. Sylloge Fungorum, XIV, p. 991, 1899. (00) Hume, H. H. Some Citrus Troubles. Fla. Agr. Exp. Sta. Bul. 53, p. 164, 1900. (03) Gossard, H. A. Fla. Agr. Exp. Sta. Bul. 67, pp. 622-623, 1903. (04) Hume, H. H. Citrus Fruits and Their Culture, pp. 547-550, Jacksonville,. Florida, 1904. (05) Sellards, E. H. Fla. Agr. Exp. Sta. Rept., pp. 26-27, 1905. (06) Earle, F. S. Primer Informe Anual de la Estacion Central Agronomica de Cuba, 1904-1905, p. 169, 1906. (06) Parkin, J. Fungi Parasitic Upon Scale Insects. Annals of Royal Bot. Gard. Peradeniya, Vol. IJ], Part I, p. 36, 1906. (06) Berger, E. W. Fla. Agr. Exp. Sta. Rept., p. xix, 1906. (07) Berger, FE. W. Fla. Agr. Exp. Sta. Bul. 88, pp. 54-65, 1907. C07) Berger, FE. W. Fla. Agr. Exp. Sta. Rept., p. xxxi, 1907. (07) Fawcett, H. S. Fla. Agr. Exp. Sta. Rept., p. xlviii, 1907. BIBLIOGRAPHY. 39 (07) Kirkaldy, G. W. ard Kotinsky, J. Board of Commissioners of Agr. and Forestry, Div. of Entomology, Hawaiian Sugar Planters’ Exp. Sta., Bul. 2, pp. 57 and 60, 1907. (08); Berger, E.. W. Fla. Agr. Exp. Sta. Press Bul. 80, 1908. (08) Cook, M. T. and Horne, W. T. Insects and Diseases of Orange. Cuba Agr. Exp. Sta. Bul. 9, p. 31, 1908. (08) Rolfs, P. H. and Fawcett, H. S. Fungus Diseases of Scale Insects and Whitefly. Fla. Agr. Exp. Sta. Bul. 94, 1908. ASCHERSONIA FLAVO-CITRINA P. HENN, (02) Hennings, P. Hedwigia, Vol. 41, p. 307, 1902. (04) Hennings. Festschrift fir P. Ascherson, p. 68, 1904. (06) Saceardo. Sylloge Fungorum, xviii, p. 413, 1906. (Co?) -Rolts, 2. Hl. Ela. Aer “xp. Sta, Rept. p. 16; 190% (07) Berger, E. W. Fla. Agr. Exp. Sta. Rept., pp. 31, 34 and 35, 1907. (07) Berger, E. W. Whitefly Conditions in 1906. Fla. Agr. Exp. Sta. Bul. 88, 1907. (07) Berger, E. W. Control of Whitefly by Natural Means. Fla. State Hort. Soc. Rept., pp. 73-78, 1907. C07). Fawcett, Hi. S: Fla. Agr; Exp. Sta) iRept., p: xiv, 1907; (08) Rolfs, P. H. and Fawcett, H. S. Fla. Agr. Exp. Sta. Bul. 94, 1908. VERTICILLIUM HETEROCLADUM PENZ. (82) Penzig, O. Flora Italica, t. 1193, Mich. II, p. 462, 1882:* (86) Saccardo. Sylloge Fungorum, IV, p. 151, 1886. (87) Penzig, O. Studi Botanici sugli Agrumi e sulle Plante Affini, p. 398, Tavola xli, Fig. 3, Roma, 1887. (04) Guéguen, Les Champignons parasites de homme et des animaux, p. 252, Baris: 19042 (06) Parkin, J. Ann. Roy. Bot. Gard. Peradeniya, Vol. III, Part I, p. 45, 1906. (07) Fawcett, H. S. The Cinnamon Fungus of the Whitefly. Fla. Agr. Exp. Sta. Press Bulletin 76, 1907. SPHAEROSTILBE COCCOPHILA TUL. (48) Desmaziéres. Ann. des Sc. Nat., Tome x, p. 359, 1848. (65) Tulasne. Carpologia, Vol. III, p. 105, 1865.* (83) Saccardo. Sylloge Fungorum, II, p. 513, 1883. (92) Cooke, M. C. . Vegetable Wasps and Plant Worms, p. 322, Plate 2, Fig. 22, London, 1892. (92) Cockerell, T. D. A. Bul. Bot. Dept. Jamaica, No. 36, p. 6, 1892. (92) Ellis and Everhart. North American Pyrenomycetes, p. 111, 1892. (94) Tryon, H. Queensland Dept. of Agr., Bul. 4, p. 15, 1894. (96) Rolfs, P. H. Fla. Agr. Exp. Sta. Rept., p. 49, 1896. (97) Rolfs, P. H. A Disease of the San Jose Scale. Fla. Agr. Exp. Sta. Bul. 41, 1897. (97) Craig, J. Canadian Exp. Farm Rept. 119, 1897. (97) Smith, J. B. New Jersey Agr. Exp. Sta. Rept. 18, pp. 470-479, 1897. (98) Smith, J. B. New Jersey Exp. Sta. Rept. 19, pp. 445-446, 1898. @98)) qRolifs. Pade Bila. Aor Exp» Stas ikeptemps 7) 1398: (98) Forbes, S. A. Ill. Agr. Exp. Sta. Bul. 56, pp..270-280, 1898. (98) Webster, F. M. Ohio Agr. Exp. Sta. Bul. 103, p. 198, 1898. (99) McAlpine, D. Fungus Diseases of Citrus Trees in Australia. Dept. of Agr. Queensland, p. 113. Figs. 181-182, pp. 27 and 28, 1899. C00) Roliss 2) He Proc Flan State torts Soc. p1i65,) 1900! C00) Earlex.