“s ie n fog nos rere eA Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. bP pk ~ Bey OF THE U. S, Department of Agriculture CEASS ea | B Soest Oe Book EnS2e a5e234 CIRCULAR No. 88. Issued May 14, 1907. United States Department of Agriculture, BUREAU OF ENTOMOLOGY, a abs : @ L. O. HOWARD, Entomologist and Chi ikea, 54 : 4 0. 1Qe gy) THE TERRAPIN SCALE. 7) “an ( Hulecanian ee Prem ceyene By J. From every State east of t Arkansas, Louisiana, Tex- as, Minnesota, and the Province of Ontario, Can- ada, the terrapin scale has been reported and authen- tic specimens have been received by this Office. It is noteworthy that this spe- cies of scale, more conspic- ‘uously marked than any other of the genus, is the most generally injurious one. In consequence of its wide range of food plants, including both wild and cultivated trees, it must be considered a dangerous pest, which may be con- trolled but never eradi- cated. This scale insect can be -recognized and identified especially well in the hiber- nating winter stage (fig. 1), when it appears as a red- dish hemispherical scale 2 mm. in length, mottled with radiating streaks of black which are especially conspicuous about the mar- gin. Sometimes these radi- ating streaks coalesce, . SANDERS, AssisiaNys he Mississippi River, and from Missouri, Fig. 1.—Terrapin seale (Bulecanium nigrofasciatum). Adult females on twig of peach. Enlarged about three times (original). forming a subdorsal dark band surrounding the central reddish boss. Occasionally individuals are found which are entirely red or black. 29931—No. 88—07 wo TD. 2 Although this species was not described until 1898,¢ the describer, Mr. Theodore Pergande, of this Office, had known it since 1872, when it was found upon peach trees at Hillsboro, Mo. hd FOOD PLANTS. For many years the terrapin scale has been considered a specific enemy of the peach and has been confounded by many entomologists and others with /ulecanium persicx (Fab.), the preeminent peach soft scale of Europe. At present we know it as infesting a large number of host plants, including many varieties of peach and cultivated plum; various species of wild plums and cherries; Prunus stmonii; apple: pear; quince; several species of Crateegus; three species of maple, par- ticularly Acer saccharinum, oriental and western sycamores: Carolina poplar; olive; blueberry (Vaccinium sp.): Bumelia, and spice bush (Benzoin benzoin). DESCRIPTION. The following technical description is inserted to facilitate the deter- mination of this species by entomologists, or anyone who may have access to a compound microscope. Adult female (tig. 2).—Nearly hemispherical, small, length 3 to 3.5 mm., exhibiting many of the superficial characters of the hibernating form described eaves though showing a tendency to fade rapidly after oviposition until by the autumn she is plain dull yellow or terra-cotta color. Fresh unrubbed specimens are covered by a thin glassy secretion of wax which scales off readily. When cleared by boiling in a solution of potassium hydroxid, the derm is left quite colorless, excepting the brown chitinized anal lobes and a narrow chitinized area surrounding the lobes. Antenne (fig. 3, 4) composed of si ; segments; segment 3, which occasionally shows a pseudo-joint, is ee ee equal in length to 4, 5, and 6 together; next in order of length nigrofasciatum): Come segments 2 and lin order. The antenne exhibit the ordi- Adult female. nary chetotaxy. Legs well developed; tibia slightly longer than RE ie (after tarsus, bearing a pair of long, knobbed tarsal digitules and a pair ier of long expanded ungual digitules. There are irregular rows of many pores leading from the spiracles to the spiracular spines (fig. 3, ¢) on the margin of the body. The median spiracular spine of each group is robust and about 50 mm. long, three times the length of the two shorter spines; marginal spines (fig. 3, d) slender, about equidistant; except four, which are closely crowded at the anterior median point. The distinguishing microscopical characteristic of this species is the irregular single or double mid-dorsal row of 25 to 40 low, subconical appendages (fig. 3, e), appearing like pores, extending from near the anal lobes to nearly above the sucking mouth- parts. These pores are usually quite evident in a mounted specimen and serve to separate this species surely from all others. The thick anal plates (fig. 3, a) are quite symmetrical, somewhat longer than broad, with the posterior lateral margin rounded and thickened. Each pe bears two minute epic and two subapical a Bul. 18, n. Aine Bats: U. Spent Agric., pp. 26-29. [Cir. 88] 3 longer sete. There are four fringe sete, the inner pair about one-half the size of the outer pair. Male.—The male of this species is a minute, delicate, two-winged insect which appears about August 1. The filmy, iridescent wings have an expanse of about 4mm. The body is rose-red, with some dark markings and a heavy brown thoracic band. This species should not be confounded with Lulecanium prunastri (Fonse.), a small, very convex, dark-red, shining species, which has a group of many (200 to 300) pores with interspersed spines, extending from the anal lobes to near the anterior margin; the spiracular spines are nearly uniform in length, being scarcely longer than the marginal spines. The latter species was first recorded from the United States in November, 1894, when it was sent to this Office from Columbia, Pa., on plum twigs. Europe is its original home, whence it must have been exported to the United States on nursery stock or cuttings. Fie. 3.—Terrapin seale (Hulecanium nigrofascia um): a, Anal lobes and surrounding chitinous area; b, antenna; c, spiracular spines; d, marginal spines; e, conical, compound pore. All greatly enlarged (original). PARASITES. Very small, parasitic four-winged flies of the genus Coccophagus. family Chalcididee, are our greatest benefactors in the control of this scale insect. REMEDIES. Unfortunately the lime-sulphur wash, which is such an excellent remedy for the San Jose scale and which at the same time controls the peach leaf-curl, is worthless for treating the terrapin scale. Numerous experiments in the use of the lime-sulphur wash against this scale on various host plants have produeed only negative results. [Cir. 88] 4 Kerosene emulsion has proved to be the most effective remedy for the control of this pest. This emulsion, when properly made accord- ing to the formula below, can be sprayed with safety on any tree dur- ing the dormant period—in winter or early spring before the buds at a strength of 20 to 25 per cent. x ody ore re ef ry NY, es — f ae e TOR ORR AREY DAS Vs aA PRROAIA EOL AR SONS view) Ary, TA <9 Sa By . é Penge * NS SON NY ; aes > 3% Otay ie ) Po) x NS RUN: A Arona es WAGES TES SECTS eae ; CANE ‘Sy » Na ee, Ree Like ") ¢ ro Ln gane, Besa A) vy) ast y a Ly Ae pat UN UA ROR Oy) oa PARRY EN UA RNEAS oe ~ CERN es * re SrA — 1‘ avy Vs ¢ Os Ax} AYR z ‘SY Oh Sty AY i A y ~, sean i < ‘< is v4 . Bess ~ “2 * ¥ man Says aver mo < se 2 iy A PA tone . ns Pyats Tesi: Wert ANON, ALANS ¢ i SAGE SN BERS PENA % CuO Suits SVORENS: 3 RST RONG eens * “i \ AY 4 Ss ORONO ‘ * MARLO AERA, SAT tate OMe a) Be Vee F7%. INAS A AY Ne We rt Na Ra We Ah + ¥ ; PAIS \ < UREN tay, TANCE “2h Lettie REN NO 2 PARES xc Tent: ANY F: vA * how " “se F s0