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OST: = a i ~ e ° > . i ie * oo an ® * 9 @ - s e ia. ee ee | oa ; h sipehenc i * irene ty ound i a fz = mi ae : RARRR ARR RRs A g U.S. OLP’T OF AGRICULTURE CEI y ED | KR w JUN 497] > I m1 FEA ie. x” eee SUR Vic > INARRARARA ARRAS Issued June 8, 1911. | U.S. DEPARTMENT, GF AGRICULTURE, BUREAU OF ENTOMOLOGY—CIROULAR No. 139. L. O. HOWARD, Entomologist and Chief of Bureau. DAMAGE TO SUGAR CANE IN LOUISIANA BY THE SUGAR-CANE BORER. BY T. C. BARBER, Agent and Expert. 89048°—11 ‘ WASHINGTON : GOVERNMENT PRINTING OFFICE : 1911 BUREAU OF ENTOMOLOGY. L. O. Howarp, Entomologist and Chief of Bureau. C. L. Maruarr, Entomologist and Acting Chief in Absence of Chief. R. 8. Currron, Executive Assistant. W. F. Taster, Chief Clerk. F. H. CarrrenveEn, in charge of truck crop and stored product insect investigations. A. D. Hopxrys, in charge of forest insect investigations. W. D. Hunter, in charge of southern field crop insect investigations. F. M. WEBsTER, in charge of cereal and forage insect investigations. A. L. QUAINTANCE, in charge of deciduous fruit insect investigations. E. F. Pures, in charge of bee culture. D. M. Rocers, in charge of preventing spread of moths, field work. Roa P. Currie, in charge of editorial work. MaBEL Cotcorpn, in charge of library. SOUTHERN Fretp Crop INSEcT INVESTIGATIONS. W. D. Hunter, in charge. F. C. BisHopr, H. P. Woop, W. V. Kine, G. N. Woucort, engaged in tick investi- gations. W. D. Pierce, J. D. MrrcHe.., E. 8. Tucker, T. E. Hottoway, G. D. Smrru, E. A. McGrecor, Harry Pinxus, W. A. Toomas, THomas Lucas, engaged im cotton boll weevil investigations. A. C. Moraan, G. A. Runner, 8. E. Crump, engaged in tobacco insect investigations. T. C. Barser, C. E. Hoop, engaged in sugar-cane and rice insect investigations. F. C. Prarr, engaged in cactus insect investigations. R. A. Cooney, D. L. Van Dine, Witmon Newett, A. F. Conrani, C. C. Krums- HAAR, collaborators. II CIRCULAR No. 139. Issued June 8, 1911. United States Department of Agriculture, BUREAU OF ENTOMOLOGY. L. O. HOWARD, Entomologist and Chief of Bureau. DAMAGE TO SUGAR CANE IN LOUISIANA BY THE SUGAR-CANE BORER. (Diatrea saccharalis Fab.) By T. C. BarBer, Agent and Expert. (The work upon which this circular is based was conducted in direct cooperation with the Louisiana Sugar Experiment Station, Audubon Park, New Orleans, La.). INTRODUCTION. The sugar-cane borer (Diatrxa saccharalis Fab.) has been the most serious insect enemy of sugar cane with which the Louisiana planter has had to contend for many years. In a bulletin of the Louisiana Experiment Station ? Dr. W. C. Stubbs gave an exhaustive account of the probable source of introduction in 1856, in cane imported from South America. He also referred to numerous cases of severe infesta- tion which occurred at various times previous to 1880. In 18808 Dr. L. O. Howard conducted investigations on this insect, and men- tioned that the first specimen was sent in to the Department of Agri- culture at Washington in 1878. He also cites several instances of previous severe infestation, one occurring as far back as 1857 ‘‘along the Lower Mississippi.””’ In 1891 Prof. H. A. Morgan published a bulletin on the ‘‘Sugar-Cane Borer and its Parasite,’ *in response to a demand for information following a severe outbreak of the cane borer in 1890. Another severe outbreak in Louisiana in 1900 was followed by the publication of Bulletin 70, referred to above, in which Dr. Stubbs gave the first statement as to the actual amount of financial damage caused to sugar cane by the cane borer (p. 889). In the case of one factory, where fair comparison was obtainable between cane 1 The form which attacks the stalks of corn, previously confused with Diatrxa saccharalis, has been found by Dr. H. G. Dyar of this bureau to belong to a new species and has been described by him under the name Diatrxa zeacolella. (See Entomological News, vol. 22, no. 5, p: 203, May, 1911.) 2Cane Borer (Diatrza saccharalis). Bul. 70, 2d ser., La. Exp. Sta., Baton Rouge, La., 1902, W.C, Stubbs and H. A. Morgan. 3 Rept. Dept. Agr., 1880, p. 240. 4Bul. 9, 2d ser., La. Exp. Sta., 1891. 89048—Cir. 139—11 2 DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. uninfested and infested for a number of consecutive years, he esti- mated the damage at $136,335 for three years on plant cane alone, or $45,445 per year, nearly $1,000 per day during the grinding season for this one factory. When it is considered that most of the area devoted to cane growing in Louisiana is infested with the borer, it can easily be appreciated from the above figures that the total financial a must be enormous. One of the special lines of work planned by Mr. D. L. Van Bees when the laboratory for the investigation of sugar-cane insects was established by this Bureau in 1910, was the determination of the various classes of injury caused by the cane borer. Observations and experiments were conducted by the writerin 1910. It was discovered that the borer is responsible for much more injury than is apparent at first sight. Its harmful work begins with the destruction of eyes of seed cane, reducing the stand during the following year; con- tinues through the growing season of the cane by stunting its growth, and causing damage from windstorms, owing to the weakening of the stalk due to the burrows and girdles; and ends by causing a much lower percentage of juice, which is again of a much poorer quality in infested canes than in uninfested canes. The last is an important form of injury, which appears to have been overlooked by investigators and planters. Moreover, the holes made by the cane borers are the chief means of entrance to the stalk afforded the various fungous diseases of the sugar cane. The tonnage yield per acre is reduced by borers, and the average weight of canes otherwise similar in appearance is found to be reduced by borer infestation. These points will be explained in detail under the following head- ings: Injury to seed cane; injury to growing cane; injury to mature cane and juice. INJURY TO SEED CANE BY THE SUGAR-CANE BORER, The buds of cane are favorite places for the attack of the young ~ borers while the stalk is growing, due to the softness of the tissue compared to the woodiness of the rind of the cane stalk in other locations. The young larve of the sugar-cane borer will enter the buds or eyes of the cane, and in nearly every case the attack will result in the destruction of the bud. Frequently canes will be seen in which more than 50 per cent of the buds have been destroyed by the borer. Of course, many borers enter the stalk at other places, around and between the joints, as an average cane will contain only from 6 to 15 joints, while canes will often be found with from 6 to 10 borer holes in a single joint. In nearly every case of severe infesta- DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. 2 tion, however, it will be found that a considerable percentage of the eyes has been destroyed. In order to secure definite data as to the extent of this injury, a number of borer-infested canes were picked up at random from a pile of cane on a property which probably represents typical condi- tions in Louisiana. The eyes were then counted until 100 were reached, and the number of injured eyes noted. No attention was paid to the amount of borer infestation in each stalk, beyond ascer- taining that at least one borer hole was visible. In the first 100 eyes counted 23 had been destroyed by the borers. On repeating the above experiment it was found that 18 eyes had been destroyed in the second lot of 100, making a total of 41 eyes destroyed out of a total of 200, or 20.5 per cent. The infestation of the plat from which this cane was secured was approximately determined at 53 per cent, which would indicate that over 10 per cent of the entire number of eyes in the plat had been destroyed by borers. The elect of this is to reduce the stand of cane the following year by reducing the number of viable eyes in the planted cane. The borers also damage the seed cane to a certain extent by absorbing a considerable amount of the sap or juice which nature intended to be used to nourish the buds when they commence to grow, but this injury probably does not assume much economic importance. INJURY TC GROWING CANE BY THE SUGAR-CANE BORER. When the cane sprouts in the spring a certain amount of damage is done to it by the larve of the first brood, which bore into the hearts of the young and tender shoots. Very frequently the terminal leaves turn yellow, and on being pulled come out of the whorl of the plant bodily. Examination reveals the fact that they have been almost cut off in the heart of the plant, and often the small worm is found in the excavation. It is likely that this source of injury causes considerable damage to the stand of cane, although no experi- ments have yet been made to determine the percentage of injury. Borers are also responsible for very considerable damage by wind- storms. After a severe windstorm in the fall the observer can notice two eilects upon sugar cane. In some cases the cane will be blown prostrate, being left lying nearly horizontally upon the ground. In other cases many of the stalks are broken by the wind, sometimes close to the ground, sometimes in the center or near the top of the cane. In the case of cane which has been blown over, it will often become more or less upright, and in any event it will continue growth. The greatest injury produced upon it is crooked and bent stalks, which are troublesome to harvest. “ 2 = =— mr . : aes —— 2 - LE TNO RT RRS EI Se RE te EE AE RR TRA AEC — 4 DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. In the event of the stalks being broken, however, the damage is very different. In this case the growth of the cane stops, and the buds on the top joints below the fracture sprout and commence to gtow. The process of growth draws upon the supply of sugar stored in the parent cane, so that the cane is not only prevented from reaching its fullest maturity, but also stands a very good chance of losing a percentage of the sugar already stored up in the stalk. A close examination of a cane field after a heavy wind will show that to borer injury is directly due the great majority of broken stalks. A cane will seldom break in a wind unless the stem has been phys- ically injured, and examination of broken stalks nearly always shows that the breaks occur at a borer girdle or a large burrow near the surface of the cane. The burrows and tunnels in the stalks frequently concentrate upon a certain joint, with the result that it will be mate- rially weakened and will snap off at the slightest provocation. Many canes are literally girdled by borers, a tunnel being made just inside the rind completely around the cane and only the center is left to hold up the top. To a large extent, also, borers are directly responsible for the spread of fungous diseases in sugar cane. In order that the fungus may enter a plant it is nearly always necessary for the spores to settle on an excision or wound in the rind of the cane. These openings are furnished in great numbers by the borer holes. Dr. C. W. Edgerton,' in ‘‘Some Sugar-Cane Diseases,”’ advises that ali “seed’’ cane showing external evidence of borer wnjury be thrown out, as a preventive of fungous diseases. L. Lewton-Brain *, in considering the rind disease (Melanconium sacchari), says: Whenever it is possible to trace the discoloration to its starting point, this will always be found to be a wound of some sort. The wound may be a borer hole, a leaf- hopper puncture, or a wound made in stripping, the borer wounds being perhaps most favorable to the fungus, especially in the older parts of the stalk. INJURY TO MATURE CANE BY THE SUGAR-CANE BORER. AMOUNT OF INFESTATION. In order to determine the extent of borer infestation an elaborate examination of canes was made during the fall of 1910. The gen- eral practice was to examine 100 canes across each end of a plat and 100 canes across the middle. These hundreds were divided into 4 eroups of 25 canes each at different points in the row. This plan was modified in varying degrees as circumstances made it necessary or advisable. In all, the infestation was approximately determined in 9 plats planted to cane. Of these 9 plats 3 were in stubble and 6 1 Bul. 120, La. Exp. Sta., p. 12, 1910. 2 Bul. 7, Hawaii Sugar Planters’ Association Experiment Station, 1907. o> DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. 5 in plant cane. The least injury to a cane by a borer served to throw it into the infested column. The general results are shown in Table I: TasBLe I.—IJnfestation by the sugar-cane borer. Number Percent- Class of cane. okeares pore eo age of in- ined. estation. SLAIN CAR CR ER mente Se neem nee < ooce te ceco es ose aseetnecomtees 1,900 603 1, 297 68. 26 Seuibolo exG earn ees Sar re ey te este arayrom is aaetaiaiale cise errete 1,100 341 759 6S ANI v OBTOER cape eae ear ai Ae kee ele LT AR 3, 000 944 2, 056 68. 52 In addition to the canes referred to in the table, two other large lots were removed from the plats for other purposes and examined for borer infestation. One hundred canes were taken from a plant- cane plat for determining the comparative weights of infested and uninfested canes. These canes were infested to the extent of 72 per cent. From a stubble plat 734 canes were removed for determining the effect of the borer upon the sugar content of the cane. Of these canes 393, or 53.54 per cent, were infested. Both of these experiments are described in detail elsewhere. Adding these counts to the pre- vious number we have a total of 3,834 canes, of which 1,313 were borer free and 2,521, or 65.75 per cent, were infested by the borer. INFESTATION OF TOPS. In five instances the same number of tops as of canes were exam- ined and showed a distinct correlation between the infestation of the two parts of the stalk, the infestation in the tops increasing to corre- spond with the increase in the infestation of the canes. This is very suggestive as to the value of clean burning of the trash after removing cane from a severely infested field. The data on this point are given in Table II: TaBLe I1.—Infestation of tops by the sugar-cane borer. Per cent Per cent Varieties. infestation | infestation in canes. in tops. JECTED Ace SBR OB O IOC SER EU se CoE Ee CES CE IPI caer Ee ge a eR a 59 § oer ae ene oa prece ee snes = wosotsone posh bSa2 cseseceosostce gececegecoreneccre 79 rf 1D) Fb ee eB ee cise See EO EIS Cs CRTs eer ange ec Ge ca Pee 81 1? SHRM OOO 3 See es Seg ER SU SENS Or OR CSE en TESS Eaten aes ee ea er 89 18 IP UNO O35 Seas Se Oo eee ae 6 Ue ae aU OBIE Cte ROOTS ie oe aie eee Sn ee en ee 95 ot CENTER OF HEAVIEST INFESTATION. That it is the tendency of the borers to seek the middle of the plat is suggested by the fact that in 4 cases the highest percentage of infestation was found in that portion, while in only 1 case was the 6 DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. lowest infestation found in the middle of the plat. On the other hand, in 6 cases out of 7, where comparison could be made, the lowest infestation was found at the ends of the plats. It may be said in general that the highest infestation will be found in the most luxuriant cane. CHARACTER OF INFESTATION IN PLANT CANE AND STUBBLE CANE. In fall plant cane the majority of the infestation is in the upper half of the cane, while in stubble cane the infestation is more notice- able near the ground, although the whole stalk is more or less infested. This may be due to the earlier sprouting of the stubble cane in the spring, thus causing it to be lable to attack from the early broods of borers; and also a certain number of borers may hibernate in the stubble, thus being present in the spring to infest the early sprouting cane. On the other hand, fall plant cane does not appear above the ground as early in the spring as stubble, and as the adults that appear in the seed cane are too delicate to dig through the soil to the surface they perish underground. A field of fall plant cane may be regarded as borer free in the spring, and will become infested during: the following summer from outside sources, probably to a degree depending upon the severity of infestation in the surrounding terri- tory. The fact that the most evident borer injury occurs in the lower half of the stalk in stubble cane makes the damage greater than in plant cane for several reasons. The first is that the actual mechanical injury by the borer is in the lower joints, which are more mature and have the greater sugar content. Again, the presence of the borer burrows and tunnels in the lower joints affects the flow of sap to the top of the cane, thus interfering, more or less, with the growth of the whole cane. Also, the joints near the base of the plant tend to become hard and woody following borer attack, thus increasing the percentage of fiber and decreasing the percentage of juice. Inciden- tally the latter point increases the difficulty of grinding, as was called to the attention of the writer by a sugar-house manager attributing the breaking of some machinery to the crushing of heavily infested sugar cane. EFFECT OF INFESTATION UPON THE WEIGH® OF CANE. In order to find out the effect of borer infestation upon the weight of cane, 100 stalks were picked out and carefully averaged in size. All were cut off the same length. No attention was paid to borer infestation in selecting the canes, and the opinions of several gentle- men were consulted, all canes larger or smaller than the average being thrown out and replaced by others until on examination it was impossible to select canes larger or smaller than the others. DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. 7 These canes were then examined for borer injury, 72 being found The smallest damage to a cane by a infested and 28 borer-free. borer was sufficient to place it among the infested canes. The canes were then weighed, with the results shown in Table III: TaB_e II].—Effect of borer attack upon weight of cane. | Loss in . | : Loss in rss Average | Number | weight ; Number | Weight Ee az weight Class of canes. weight | of canes | per ton = of canes. | of canes. per cane.| per ton. | due to See borer. i Pounds. | Pounds. Pounds. | Per cent. [BORE RIK Sa eO Bo AES aes eto ue eae 28 103 3. 68 04850) Wasa tee ese Rone eer ee iBorerinteste desis learn use aye eat 72 255 3.54 565.0 76.0 | 3.8 For further results a wagonload of cane was taken to the sugar- house, and was there separated into two lots, infested and uninfested. Of the 734 canes, 393, or 53.54 per cent, were infested. The least injury by borers placed a cane in the infested lot. Each lot of cane was then weighed separately on platform scales. The 393 infested canes weighed 694 pounds, an average of 1.76 pounds per cane, while the 341 borer-free canes weighed 626 pounds, or an average of 1.84 pounds per cane. TaBLE I1V.—Loss of weight due to borer attack. b nO8s an Loss in ee Average | Number] weight aes Canes. Sue aN fen weight | of canes | per ton pei : *| percane.} per ton. | due to Barer borer. : Pounds. | Pounds. Pounds. | Per cent. PBOTEIAMeCC oe bes kaa OEM Wa Os OBER Dale 341 626 1.84 POSTE BRAG SAS 0D leery IB OLEE-MTeS LE Cie saeee eee eee eee 393 694 1.76 1,136 86. 24 4.31 On the basis of Table IV the difference in yield between borer-free and borer-infested cane fields would amount toa loss of about 1 ton of cane per acre when the borer-free cane gives a yield of 25 tons per acre. EFFECT OF BORER INFESTATION UPON CANE JUICE. The following series of experiments was carried out to ascertain just what damage the cane borer inflicts upon the cane juice, in addition to the physical damage to the cane plant: Expervment 1.—Six stalks of D. 74 cane were selected, three being heavily infested by the borer and three being borer-free. The stalks were cut into four samples, as follows: (1) 34 bottom joints, borer-free canes. (2) 34 bottom joints, borer-infested canes. (3) 34 top joints, borer-free canes. (4) 34 top joints, borer-infested canes. 8 DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. Samples 1 and 3 and samples 2 and 4 were thus from the same canes. Each sample was carefully weighed, run through a 3-roller hand mill, and the weight of juice from each sample recorded. The juice was then analyzed, the latter operation being kindly performed by Mr. W.G. Taggart, chemist at the sugar experiment station. Sample 2 (bottom jomts) showed, compared with sample 1, losses due to the borer of 4.59 per cent of juice, 2.6 per cent total solids, 4 per cent sucrose, and 12 per cent purity, and an increase of solids not sugar of 0.8 per cent. Sample 4 (top joimts), compared with sample 3, showed losses of 7.27 per cent of juice, 4.2 per cent total solids, 4.9 per cent sucrose, and 13.7 percent purity, and an increase of solids not sugar of 0.8 per cent. It can thus be seen that the borer not only reduced the Juice quantitatively but qualitatively as well and to a more marked degree. Placing these figures on a basis of 1 ton of cane to the sample, we have the following results: Sample 2 showed losses of 91.8 pounds of juice, 35.2 pounds of total solids, 59 pounds of sucrose, and a percentage loss of sucrose of 34.04 per cent. The increase in solids not sugar was 8 pounds per ton of cane. Sample 4 showed losses of 145.4 pounds of juice, 68.6 pounds total solids, 70.9 pounds sucrose, and 46.43 per cent sucrose actual loss, with an increase of solids not sugar of 5.4 pounds per ton. The average production of the total borer-free cane (samples 1 and 3) was 163 pounds sucrose per ton of cane and of the total mfested cane (samples 2 and 4) 98.1 pounds sucrose per ton of cane. This gives an average loss of 64.9 pounds, or 39.81 per cent, of sucrose per ton of cane due to the borer. The results of this experiment are given in tabular form in Table V. TaBLE V.—Analysis of sugar cane (D. 74) to determine effect on sugar content of the borer injury to sugar cane. : ‘ 5 |@ = bw © : s | 8 | 2 ays ee lee S| 8 Se Nee = os) 3 = cS: -| So 5 2) = = 5 = = 3 = o = = (OR! 3 | m= |S] 26 = = B} Nature of sampl Ss | 3 |S ess loo | 8 |S) es] a | es aS iG Nature Of Sample. ae aa = =O as in 4:| 2 2 q.2 O qo < Be S a co ®9 1S6|4—| Sei oS o| 4g ira lips |e te 2 = a =~ o |ye| 8 nso) S|/s-/] «& eSlel2s S RSIS WOR Sa We NH ecg ic tle I s | eo | 5) e0 yA - - loo I ee i= = st eo) TM RM 4] _ — cre | Cee Pa — ee | | 1 | 34 bottom joints borer- |Grams.|Grams.| Pt. P.ct.| P.ct.| P.ct. PRCT OV det Ces | eee Fok Ife CANGS: J. eu o.- 2% fle Shey 419/62. 33]....] 16.6)...... 1.3] 9.3) 14 wake <|Gosmieweee 2 | 34 bottom joints borer- | infested panes roe | 1,008 582/57. 74/4. 59) 140) 2.6) 1.9)19.2) 2.2) 9 9 4.0.71. 7) 12.0 3 | 34 top joints borer- ITEC 'CANCS | aon wc ute 1, 282 780|01. O08). 02|| ALG See. gO Vi eC pie tS) Coat be * 45 - (Sil Se 4| 3k top joints borer- infested canes....... | 985 530/53. 81)7. 27) 11.9 4.2 1.3)17.1; 3.0 (é 4 4.9 64.9) 13.7 i Note.—Samples 1 and 3, 2 and 4, were from the same canes. Each sample consisted of portions of three canes. Analysis made Novy. 10, 1910. DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. 9 TABLE V.—Analysis of sugar cane (D. 74) to determine effect on sugar content of the borer injury to sugar cane—Continued. RESULTS OF ABOVE ANALYSIS FIGURED ON A BASIS OF 1 TON OF CANE TO THE SAMPLE. : Ho Ww = ltalls D (<0) =I nod 4 fe) 2 ‘3 Saray ices li a eemesies IPeenleoee nt Gyo) SS by Bier h | Sees ae = Sele ee inn oes e lee .2 3 |e | Sere E = = tas |Z S5| 8 os |2|?s8.| 8 |881]88 = re) 3 pany a on Tos a a ee ees alee lesley 86 | ae, ee sie ol cell ee S S| & lagsla w=] 8 | Se}salsecl & | asl ag 3 2 S@ (2485/6 |440) 2 | sss igs8] § | 36] Ss Z, = eo aS eH | Sa See (tea | oD Sen 1 | 34 bottom joints borer-| Lbs. | Lbs. | Lbs. | Lbs. | Lbs. | Lbs.| Lbs. | Lbs. | Lbs. | Lbs. | Lbs. | P. ct. TRECICATICS eee pene 2, 000)1, 246. 6}... .-.- 20699 | Beare G52 |eeeeee WEAN eee W36) poco lesoe- 2 | 34 bottom joints borer- infested canes ...... 2,000:1,154. 8} 91.8) 171.7) 35.2) 21.9) 5.7) 25.4) 8.0) 114.3) 59.0) 34.04 3 | 34 top joints borer- TRECICAMES eas see ea 2 OOO 22156 canes WW Wososas Mes osce 2659 | eee DS 2orfl Sse os | eee 4 | 34 top joints borer- infested canes...... 2, 000)1, 076. 2) 145. 4| 128.1) 68.6) 14.0|\— 3.1! 32.3) 5.4) 81.8) 70.9] 46. 48 Average weight of su- crose per ton: Se Haay eS WaYol Bias Meee ele Se Nee Mey I Ree Al ese Les | ae | 163: Ole ase S BETES} sea Cl Aes | es te eal | epee pa a a ee no ee 98.1) 64.9) 39. 81 Experiment 2.—The remarkable figures obtained in Expervment 1 showed the advisability of conducting a further experiment upon a larger scale in order to obtain more conclusive results. For this experiment 30 canes were selected at random from D. 74 cane. Of these 10 were borer-free, 10 were medium infested (1 to 3 joints per cane showing borer injury), and 10 were heavily infested (5 or more infested joints per cane). It should be remarked that the infestation in the heavily infested canes was not so heavy as was the infestation of samples 2 and 4 of the first experiment, in which every jot was infested. Each sample of 10 canes was separately weighed, run through the hand mill, and analyzed exactly as had been done with the samples of the first experiment. The analyses were again made by Mr. W. G. Taggart. The results obtained fully upheld those of the first experiment. Sample 2 (medium infested) showed losses due to the borer of 0.3 per cent juice, 1 per cent total solids, 1.2 per cent sucrose, 2.2 per cent purity, and an increase of solids not sugar of 0.1 per cent. Sample 3 (heavily infested) showed losses of 2.3 per cent juice, 3.4 per cent total solids, 4.6 per cent sucrose, 12.7 per cent purity, and an increase of 0.7 per cent solids not sugar. Reduced to a basis of 1 ton of cane to the sample, the results were as follows: Sample 2 (medium infested) showed losses per ton of cane of 6 pounds juice, 13.19 pounds total solids, 15.46 pounds sucrose, 8.78 per cent actual loss of sucrose, and an increase in solids not sugar of 1.15 pounds. Sample 3 (heavily infested) showed losses per ton of cane of 46 pounds juice, 47.85 pounds total solids, 10 DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. 60.72 pounds sucrose, and an increase in solids not sugar of 7.73 pounds. Comparing the percentage loss of sucrose in the heavily infested cane of this experiment, 34.51 per cent, with the average loss of samples 2 and 4 in the first experiment, 39.81 per cent, and con- sidering that the latter cane was more thoroughly infested than the former, it will be seen that the results of the first experiment were not Beagocrated to any great degree by reason of the smallness of the samples. The complete results of this experiment are shown in Table VI. Taste VI.—Analysis of sugar cane (D. 74) to determine effect on sugar content of the borer injury to cane. pees | | . ee (ed etal Ae Ce mae a |Q | > q 2 ar is S | & ie eke a eh [= 63 S| Natureof | 6 | 3 | 88/35/38 |e? | 8/88] & | 8 | 28 We BARON ce Be SS eee) Sead ee ee | en) eee 280 R= ne | 3 n=6| oO ohm =) Bn nen = | 2 S| Sol B yee (8 (ey eeel sea he Sy eal Tie Z| EE ler, ie ie eS ane ee ec anne (ve f= fy |S z Gms. | Gms. P.ct.| P. ct.| P. ct.| P. ct.| . ct. P: ct. P. ct. 1 | Borer-free....... 9,990 | 6,108 | 61.1 |..--- aly 52 big (See Pe ME] oa | she ae Say Ze ea 2 | Medium infested/11,081 | 6,735 | 60.8 | 0.3] 16.1] 1.0] 1.7] 1.2]129]| 13.2] 1.2|820] 22 5,190 | 588123 (13.71 34) 21) LS) S42) OS | LET iatisy 3 | Heavily infested 8, 824 NotEe.—Each sample consisted of 10 canes. Each of the medium-infested canes contained from one to puree infested joints, and each of the heavily infested canes five or more infested joints. Analysis made ov. 12, 1910. RESULTS OF ABOVE ANALYSIS FIGURED ON A BASIS OF 1 TON OF CANE TO THE SAMPLE . . . [| fw | =—30 = o>) fe a . . -—« cs E ¢ |g igs |g |38 | ¢ 12./8 loge] g | 2. BS = S Seiwa So = oo 3 i sol > Te bees 5 | o | = |8e | 4 = s les) @y lq@al"e |a6 Tae =) Nature of S Poe ee = J 7 roy wo] BS Te s ao |9- =e a8 = ro) SH loo ae ee sample. 2 ao VAST teal Puaees. || eels 2 aR A, Agr © q#2\Wo% ro) = ee Ne eye) Ieee =e rs) SS HO Iw), pape (Gs is 2 2 |nis| 3 aao| 9° 23/0 Pes! # a% |Bao 2 © © |682! 6 oats ess eis tel 2=s| 3 $a oak Zi S Si 1 = = Oo es] D AS D 4 < | OE aN (Cen ere ( 2 | (pP e | ee S Bente Lbs. | Lbs. | Lbs Lbs. Lbs Lbs. | Lbs. | Lbs. Lbs. | Lbs. | Lbs. | P..ct 1 |, Borer-free..-..-- fas MOOI sill De i tee 208; 96) saan 19755 \[-c5 << 13. 44 bers oe 175, OT) fee eee 2| Medium in-| feSted. 2. =. ] 2,000 | 1,216 6 | 195.77 | 13.19 | 20.67 | 1.12 | 14.59 | 1.15 |160.51 | 15. 46 8. 78 3 |} Heavily in- a fested.. 2,000 | 1,176 46 | 161.11 | 47.85 | 24.69 | 5.14 OLY 1 Weve pw 25 | 60.72 | 34.51 Experiment 3.—In order to confirm the results of the two foregoing experiments, and also to secure additional accurate data upon a larger scale, a third and larger experiment was conducted early in December, 1910. A wagonload of D. 74 cane was taken to the sugar house and was there divided into two lots, borer-infested and borer-free, the least sign of borer injury throwing a cane upon the infested pile. Of the 734 canes, 393, or 53.54 per cent, were infested. Each pile of canes was loaded separately upon a wagon and weighed on the platform scales. The 393 infested canes weighed 694 pounds, DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER. ame an average of 1.76 pounds per cane, and the 341 borer-free canes weighed 626 pounds, an average of 1.84 pounds per cane. This gives an average loss in weight of 0.08 pound per cane. In 1 ton of cane like each of these samples there would be 1,087 borer-free canes and 1,136 borer-infested canes; or, in other words, it would require 49 more infested canes to make a ton than of borer-free canes. On a crop basis of 25 tons of uninfested cane per acre, this would show a loss of about 1 ton of cane per acre due to the Borer! Each lot of cane was then run through the mill separately and a sample of the juice taken. The 626 pounds of borer-free cane gave 431 pounds of juice, or 68.85 per cent extraction, while the 694 pounds of infested cane gave 455 pounds, or 65.56 per cent extraction. The loss of juice due to the borer was thus 3.29 per cent. The two samples of juice were analyzed by Mr. W. G. Taggart, and showed a loss due to the borer of 1.5 per cent total solids, 2.1 per cent sucrose, and 5.6 per cent purity, with increases of 0.1 per cent glucose and 0.5 per cent solids not sugar. Figured on a basis of 1 ton of cane per sample, the losses are 66 pounds of juice, 30.69 pounds total solids, 36.57 pounds, or 19.33 per cent, sucrose, and increases of 0.72 pounds glucose and 5.17 pounds solids not sugar. The results of this analysis are shown in Table VII: TasLe VII.—Analysis of sugar cane (D. 74) to determine effect on sugar content of the borer injury to cane. ace ot 2 = Zs g 2 : PAS SM hie Sol eee ttle alierne ibe oh ek bs . |2 | Purity ae een lines 22} o © oH o | 8 ily eur tess g Sie eyes | eS tery 5 Qa, /|n aD eb o| «= |s¢ S ° ie 2 EI = _= os) ° =5 = Bo Ter =) 5 Nature S) at gad} Bo} = 4 oO |S a2 = a 5 = | 29 oa lo) S or a s BR pas S = g 3 fa} = o of ro) 1) S >) © = o-S ° 45 fae al Ss 40 Ae} Bes : ~ Ors, 2 ; » (Q as |+°e o's a ot do) & los sample. | | 3 /Ssl/a3|/2| 8|se| =as| 8 |S2!a] ¢ |FS| 8 |g ABO = ie D sy 5 na =) as 8 ye} 5 o lnas| 2 ae S is © Ae (5) far “a 3 nes — piss 53 5 AT) 7) S = > e8 o ° ° ce} a= iS) lar = 1° Di | Ore F|4l\a os|e Arles = 4 Go |M Ci Parniel i | Lbs. Lbs. | Lbs. | Lbs. PACES | JP eb peach. Este | "Pct: IPNch IPECE Borer-free.| 626) 341) 1.84/....-- 431} 68. 2 ae Se UGS Wee kee O29) 72-69 13277) S250 fore Infested...} 694) 393) 1.76) .08}| 455) 65. ea Be2O bei eee Sen ell 2G eSiG|h alk Gle2sblaiGy4 ea buG NotEe.—The above samples of cane constituted a wagon load which was taken to the sugar mill and there separated into infested and noninfested lots. There was no selection of canes in the field and the least borer injury served to throw a cane into the infested samples. December 13-14, 1910. RESULTS OF ABOVE ANALYSIS FIGURED ON A BASIS OF 1 TON OF CANE TO THE SAMPLE. n >) 43> 53 fo) = ig e PN ite = ad af Set ae a OW IR Sas 1088 Bio. |) eo (ais Ss | Fes See Seals We SS Ue) Se BB age Nature of | aay Bs = $2 2 - oe 2 oF sample. ae eee Ca tou aa Oeil) ct os 3 ees | #8 a RS oo ie ‘cis 6 | go a gD a © Sv So een Mien eae aS neces liyas Le me) mt am coke S 2 8 eB Do 5 OU 3 S & g Bo i 8 Be 4 Be | A Sris R fs R 4 a5 Lbs. | Lbs. | Lbs. | Lbs.| Lbs. | Lbs. | Lbs. | Lbs. | Lbs. | Lbs. | Lbs. | Borer-free..| 2,000] 1,377|..-...-- lspgt gehen 214 Woxeg Wie Dero ieee a 1G8V'65| 45) oe eee Infested....| 2,000| 17311 66|199.27, 30.69] 13.11) 0.72} 34.08 5.17] 152. 08 36. ay 19. 33 | ean | 12 DAMAGE TO SUGAR CANE BY THE SUGAR-CANE BORER, It should be noted as having a bearing on all of these analyses that the lower the purity of the juice the lower is the percentage of total sucrose that is recoverable in the form of sugar. Therefore the percentage loss of sugar in the impure samples somewhat exceeds the loss of sucrose. The sucrose which can not be recovered is approximately equal in amount to the glucose present. On this basis the present experiment would show a production of 176.26 pounds sugar per ton for the borer-free cane, while the borer-infested cane would give 138.97 pounds sugar, a loss of 37.29 pounds per ton of cane, equaling a loss of 21.16 per cent sugar, which is 1.83 per cent in excess of the sucrose loss. It may be computed from the figures in Table VII that an acre of borer-free cane yielding 25 tons of cane of the above quality would yield 4,716.25 pounds sucrose per acre, while if it were infested to the same degree by borers, the yield under similar conditions would be 23.92 tons of cane and 3,637.75 pounds of sucrose per acre—a loss of 1,078.50 pounds sucrose per acre. } SUMMARY. The sugar-cane borer damages cane in the field by destroying a considerable percentage of the eyes, thus reducing the stand of plant cane; by stunting the growth of the cane, owing to the physical injury of the stem; by admitting fungous diseases through the wounds in the stem; and is the main cause of injury by the wind, owing to the weakening of the stalk due to the tunnels and burrows. These classes of injury have been appreciated by planters. It now develops that there is another and very important class of injury which has been overlooked. This is the reduction of both the quantity and quality of the juice, which is dealt with specially in this circular. It becomes evident that both the planters and the man- ufacturers are vitally interested in the work of the sugar-cane borer. Investigations of methods of control in the field are now under way. The results will be published in due time. In the meantime planters are referred to the bulletin on the subject (Bulletin 70), by W. C. Stubbs and H. A. Morgan, of the Louisiana Experiment Station. O seo ai . a iG vont wipe Hi | om ar ' a ; Bs, Ox eda: L2% GN “i Raia pei 6 * ' ‘ *, ea os 2 Ae wer} CEN hte he wold mh ome fertile “ag mn : 8 ee? eves yee Santis eS pie havea shies Cae Sy ate ats haan ical | An ae aia a eines hee te ets il Me Gna a eng wh wi? ae , iy , pt F OOkE ocr bbe % bake it i‘ Le VRE | pads f = ‘ | \ ao Ras the? he aa? kee: Sj eraitan! tytn ste ‘anne ee ne Of that Re | RM Ree ays. GMM! Tee a gelhe, ah ea Howgeatyen EOS CR Ce a eee Sse ewe OSS . RMN a oan” 2, IT. ae fi ae Hy a _ ss Aiea SNRs S > OO >.