December 1962 ~OVERO ET AL.: INTERRELATIONS OF SQUASH BUG & SQUASH VARIETIES 919

Beard, R. L. 1940. The biology oCAnasa tristis (DcGeer) with Hoerner, J. L. 1938. Controlling the squash bug. Colorado particular reference to the tachinid parasite, Tricho- Expt. Sta. Press Bull. 93: 1-8. 'pod(~ pennipes Fab. Connecticut Agric. Expt. Sta. Knowlton, G. F. 1952. Controlling the squash bug. Utah Bull. 40: 597-680. State Agric. College Ext. Circ. 164, '! pp. Eichmann, R. D. 1945. Squash bug depredations in Washing- Pack, H. J. 1930. Notes on the miscellaneous insects in Utah. ton, Jour. Econ, Ent. 38: 110-1'!, Utah Agric. Expt. Sta. Bull. 216: 21-22. Gould, G. E. 1951. Squash bugs in Indiana. Indiana Acad. Painter, R. H. 1951. Insect resistance in crop plants. New Sci., Proc. 60: 190. York: Macmillan Co. 520 p.

Effect of Sesamex on Toxicities of Individual Pyrethrins1 Downloaded from https://academic.oup.com/jee/article/55/6/919/2207467 by guest on 28 September 2021

SIHJNCHIN CHANG2and C. W. l\"EAHNS,Department of Entomology, Um:1Jersity of Illinm:s, Urbana

ABSTRACT The present study was made to evaluate the relative T ndividual pyrethrins, separated b,}'colulUn chrolUatography toxicities of the four components of pyrethrum obtained of natural pyrethrullls, wcre tested topically against Cemaleand by chromatographic methods, to obtain LD.o values in male house Bies (jJ[usca domestica L.). PyrethrinlI, cinerin I and terms of J.l.g.per fly, and especially to determine the inten- cinerin II were, respectively, about 58%, 23% and 25% as toxic sity of synergism in combination with sesamex.3 The as pyrethrin 1. However, in combination with sesamex, the latter information is necessary for elucidation of the toxicity was increased 60-fold with cinerin I, 17-fold with pyre- mechanism of synergism in relation to the structures of tll1'in T, 13 to 22-fold with cinerin II and only 8-fold with pyre- pyrethroids. thrin II. An unique device oC a micro-applicator was described. MATERIALSANDMETHODS.- The indi vidual pyrethrins were separated from pyrethrum concentrate by column Since LaForge & Barthel (1945 a and b) discovered a chromatography (Chang 1961). Purities were further second keto-alcohol or cinerolone in addition to pyrethro- checked by thin layer chromatography. Sesamex was lone in the course of study of the constituents of pyreth- provided by Shell Oil Company and was shown to com- rum flowers, the four active components, i.e., pyrethrin prise two components of approximately equal proportion I (PI), cinerin I (CI), pyrethrin II (PII) and cinerin II when chromatographed on Florisil columns. Since both (CII) have not been isolated by physical means in this components show identical ultraviolet spectra, colorime- country until recently (Chang 1961). Gersdorff (1947), tric reactions, and synergistic actions, they were consid- using four re-synthesized esters, obtained data on toxicity ered as a single identity. tests on house flies (Mll.~ca domestica T>.) using kerosene The ''\Tilson strain of house flies was used for this study. sprays. He concluded a) that PI and CI were about 4.3 This strain, which is a normal or susceptible strain, was and 4.0 times as toxic, respectively, as PII and CII and reared in a room maintained at a constant temperature of b) PI and PII were about 1.5 and 1.3 times, respec- 80° F. Standardized fly-rearing procedures were followed, tively, as CI and CII. A similar ratio of 4.4 between the employing the CSl\1A (Chemical Specialties Manufac- chrysanthemie acid and pyrethrie acid esters has been turers Association) fly larval medium, yeast, corn syrup also shown with allethrolone (LaForge et al. 1952). Ineho and water. The flies emerged from one rearing jar were & Greenberg (1952) separated the active components of used for tests of one individual pyrethrin alone and in pyrethl'Ums by regeneration from the respective semi- combination with sesamex to insure the homogeneity of carbazones. These workers compared the relative effec- fly populations so that the intensity of synergism could be tiveness to house flies of pyrethrum sprays and confirmed precisely determined. the same general order of toxicities as reported by Gers- Flies from one rearing jar were anesthetized with car- dorff. Ward (1953) evaluated the relative effectiveness of bon dioxide and sexed. The flies were divided into groups these components to Phaedon cochleariae. Using natural of 55 directly into I-pint, wide-mouth glass Mason jars. A constituents separated by displacement chromatography screen wire lid was added. The flies were fed 5% sugar and applied topically he found that PI was 2.6 times as water overnight to allow them to recover from the effects toxic as PII, and CI was 2.5 times as toxic as CII. Sawicki of anesthesia and handling. Immediately before treat- & Thain (1961) used Ward's chromatographic technique ment, any dead flies, usually less than 1% of the total, to separate the constitutents which were tested on house were crushed by a small rod through the top screen fly females by topical application. They found that the so that they could be recognized and not included in the relative toxicity of three of the four constituents at treatment. Each group of 50 was lightly anesthetized with 0.075% concentration in acetone was PII 130, PI 100, and CO2• The Mason jar was covered with a plate glass which C160.

The enhancement of toxicities of the separate compo- I This study was supported by a research grant from the U. S. Army (Contract nents of pyrethrum by sesamex (S) has not been reported No. DA-CML-18-108-61-G-4). Accepted for publication May 4, 196~. 2Formcrl~' Ucsearch Assistant Professor, Department of Entomology, Uni· in literature. lncho & Greenberg (1952) reported that the versity of Illinois, Urbana; now Research Chemist, Pesticide Chemicals Re- synergistic effect of piperonyl butoxide, when combined search Branch, Entomology Research Djvision, Agricultural Research Service, with the individual active components of pyrethrum, is BeltsviJIe, Maryland. • A sample of s"-"ames was obtained throngh the court"-"y of Shcll Develop- CI >CII >PI = PII in the decreasing order. ment Co., Mod"-"to, California. 9~O JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 55, No.6

o Downloaded from https://academic.oup.com/jee/article/55/6/919/2207467 by guest on 28 September 2021

FIG. l.-PhotograpJl showing the assembly for topical applications. A fritted-glass container (A) for anesthetizing flies; a glass Mason jar (D); a trap device (C); a glass tube (D) for air inlet; an aluminum block (E) for mounting the syringe; a micrometer(F) with a shallow groove cut on the spindle (G); a click device (II) with pin and spring inside the housing; a metal tube (I) to be slipped over the thimble of the micrometer for backing. The pin at one eud of the metal tube is to be engaged into the slot of an alllll1iullll1rod (J) which, in turn, is attached to a motor. had twoholes (figure 1). One hole was attached to the air in acetone solution. The ratio of pyrethrins to sesamex in line. A gentle air stream evaporated the solvent and mixtures was maintained at 1: 10. Fifty flies were used for avoided excess moisture in the container. The other hole each concentration. Tests on CI alone and CI plus sesa- was attached to a trap device, which was made of a series mex were repeated once. The mortality data were re- of three glass funnels (figure 1). Each individual fly after corded after 24 hours and were pooled before probit topical treatment was put into the Mason jar through analysis. All other pyrethrins or mixture of pyrethrins and this glass trap device. Therefore the flies were not subject sesamex were tested only once. to any undue exposure of CO2• Flies treated in this fashion The actual number of flies in each jar was rechecked by with acetone as control, usually showed no mortality. The killing the living flies in an oven and counting the total flies were treated at the rate of approximately 500 per number of flies in the jar. Two moribund flies were hour, including time spent changing or replenishing counted as one dead. For each series, a regression equation solutions in the syringe. of probit-mortality on log concentration was computed as The acetone solutions of pyrethrins or of pyrethrins and described by Finney (1952). No attempt was made to fit sesamex were applied topically to the mesonotum of flies all lines with a common slope. The intensity of synergism from a Hamilton syringe (No. nON) attached to a mi- was measured by the ratio of the LD50 value of the toxi- crometer. A simple click device (figure 1) was mounted on cant alone to the LD50 value of the toxicant in mixture the micrometer for repeated delivery of constant volume with sesamex. Sun & Johnson (1960) called this ratio the (0.8547 J.d./fly). A longitudinal shallow V-shaped groove co-toxicity coefficient. However, they used a constant was cut in the micrometer spindle. At the end of the level of synergist instead of a definite ratio of toxicant to barrel was mounted a steel pin with a spring. The pin synergist. By this method if the numerical ratio is signifi- engaged in the groove at every complete turn of the cantly higher than one, the mixture indicates synergism, spindle. When the thimble reached the zero mark on the if less the result shows antagonism. Thus the co-toxicity barrel, the pin could be lifted up to disengage from the coefficient is the extent of increase (or decrease) in tox- groove. A metal tube was slipped over the thimble. A vari- icity. speed motor, operated by a foot switch, was used so that RESULTS AND DrscussION.-The results of 16 tests the spindle could be backed all the "\'I'ayout in a few sec- with pertinent data are listed in table 1. The computed onds. A circular depression was cut at the end of the Chi-square values were significant at the 5% probability syringe plunger and was used to engage with the mi- level in only three out of 16 tests. Hence the probit regres- crometer spindle to insure proper alignment. sion lines appear to be a satisfactory representation of the Five graded concentrations of pyrethrins were prepared results of the 13 experiments. Of the three significant December 1962 CHANG & KEARNS: EFFECT OF SESAMEX ON TOXICITIES OF PYRETIHUNS 921

Table I.-Results of toxicity tests of individual pyrethrins or pyrethrin plus sesamex.

DEGR"~;S Co- LOG PlWBIT-LoG OF TOXICI'l'Y !'nn;- LD,. (LD,.X103) REGHESSION FlmE- R"LATIVI, CO"I'FI- THlllNH FLY S"x /Jg/FLY ±S,E. EQUATION S.E. (ll) X2 DOM TOXICITY CmN'Ia ------PI alonc Malc 0.301 2.478±0.026 y=4.26X -5 .56 ±0.41 ] .711 2 100 PI & S .Malc 0.018 1.267± 0.022 y=6.13X-2.77 ±0.69 3.50 '2 ]6.7 PI,donc :Fcmalc 0.548 2. 739± 0 .027 y=4.38X -6.98 ±0.30 I. 20 2 ]00 PI &S Fcrnnlc 0.034 1. .530± 0.034 y=3 . .51X -0.34 ±0.46 1.32 2 Hi. 1

PII ,donc Mulc 0.5]3 2.710±0.030 1}=3.82X -5 .34 ±0.43 0.71 2 .58.(j PH &5 .Malc 0.06.5 1.812±0.028 y=4.31X -2.79 ±0.50 3.11 2 7.9

PH nlonc FClIlale 0.1l4'2 'UJ74±(},029 y=3. 70X -.5.1111 ±0.41 o. ]7 2 58.'2 Downloaded from https://academic.oup.com/jee/article/55/6/919/2207467 by guest on 28 September 2021 ])II &S 'Fcmnle 0.107 2. 030± (),023 y=5. ]3X -.5.3fJ ±O.34 0 ..51 2 8.8

CI nlonc Mnlc ] .380 3 . 140±0 .027 1}=2.97X -4 .33 ±0.31 7.02 3 21.8 CI &8 Male 0.024 1.376± 0 .0'lO 1}=4.94X-1.81 ±0.0.5 .5.75 3 57 ..5 CI al<'ne Female 2. ]68 3 .336± 0 .028 y=2.80X -4.34 ±O.24 8.60b 2 25.3 CI &8 l~emale 0.036 1..560±0.029 y=3.4.5X -0.38 ±0.39 ]3.03h 3 (i0.2 cn alone Male 1.12'l 3 .0.50±0 .031 y=3 .87X -6.79 ±0.49 2.74 2 '2(i.8 cn &8 Male 0.084 1. 92.5± 0.034 y=3.]8X-1.]'2 ±O.36 1. ]4 'l ]3.3 cn alone Femnle 2.34.5 3.370±0.030 y=3. 78X -7.73 ±0.4'2 (i.fJ8h 2 23.4 Clr & S Female 0.106 2.025±0.039 y=3.14X-1.36 ±0.43 5.50 2 22.1

LD.o or toxicant alone (\ Co·toxicily coeiHcient = ------.- ]~])~Oor toxicant in mixture b x' significant at 0.0.1 probability le\'el.

Chi-square tests, the value of 8.60 and 6.D8 (table I) is not was potentiated to the largest extent and PII the least by significant at 0.01 probability level although the value of sesamex, an increase of about 60-fold and 8-fold in tox- 13.03 is still significant at this level. icity, respectively. The toxicity of ]~I and CII was in- The slope among the 16 regression lines varied froll1 creased about 17-fold and 13- to 22-fold, respectively, by 2.80 to 6.13. '''hen tested alone, the individual pyrethrins sesamex. It should be pointed out that even after potenti. showed approximately the same slope for both males ation the mixture of PI and sesame x is sti II more toxic and females. However, in tests with pyrethrin-sesamex than the mixture of CI and sesamex by a factor of about mixtures, the slope increases or decreases without any 1.1 to 1.4, owing to the inherent high toxicity of PI. On regularity, depending on the sex of Hies and components the othet· hand, the toxicity of CI plus sesamex is about tested. The regression lines for PI and PII, alone or in 12.5 to 15 times more toxic than PI alone. The data is in combination with sesamex, in either male or female series, good agreement with Incho & Greenberg (1952) on the do not cross over in the range of I % to 99% mortality potentiation of toxicities of individual pyrethrins by levels. However, the regression lines for CI and CII when piperonyl butoxide. applied alone, cross over at 13% and 61% mortality level for male and female flies, respectively. When applied in REFERENCES CITED combination with sesamex, the regression line for CI Chang, S. C. 1961. Chromatographic separation of active crossed over with that for PII at II % mortality for male components of natuml pyrethrins and their character- series and at 50% mortality level for female series. izations. Jour. Agr. and Food Chern. 9: 390-394. Based on J"D50 values, the male flies are approximately Finney, D. J. ]952. Probit Analysis. Cambridge at the Uni- 1.6 to 2.0 times more sensitive than female flies. Thus, versity Press. London, England. sexing the flies provided two independent tests on a single Gersdorff, W. A. 1947. Toxicity to house flies of the pyre- component alone or in mixture with sesamex. thrins and einerins and derivatives in relation to chemieal strueture . .Jour. Econ. Ent. 40(6): 878-82. The relative toxicity of individual pyrethrins was Incho, H. H., and H. Greenberg. 1952. Synergistic effect of represented by the ratio of the LD.o value of PI to that of piperonyl butoxide with the active principles of pyre- each of the other three pyrethrins and multiplied by 100. thrum and with allethrolone cstcrs of chrysanthemum The results showed unequivocally, that PI is the most acids. Jour. Eeon. Ent. 4.5(.5):794-9. potent, and PII is approximately 58% as toxic as PI. CI LaForge, F. B., and W. F. Barthel. 1945a. Constituents of and ell have about equal toxicity and are approximately pyrethrum flowers. XVIII. The structure and iso- one-fourth as toxic as PI. In order to discern the relative merism of pyrethrolone and cinerolone. Jour. Organ. toxicity of CI and CII, a more discriminating test would Chem. 10: 114-20. be desirable. Our data on relative toxicity of individual LaForge, F. B., and W. F. Barthel. 1945b. Constituents of pyrethrum flowers. XIX. The structure of cinerolone. components of pyrethrins differs from Gersdorff's (1947) Jour. Organ. Chern. 10: 122. who reported a ratio of 4.0 to 4.4 for chrysanthemic acid LaForge, F. B., W. A. Gersdorff, Nathan Green, and M. S. and pyrethric acid esters or a ratio of 1.3 to 1.5 between Schechter. 1952. Allethrin-type esters of cyclopropane pyrethrolone and cinerolone esters. carboxylic acids and their relative toxicities to house The intensity of synergism was indicated by the co- flies. Jour. Organ. ChelIl. 17: 381. toxicity coefficient. The data indicated clearly that CI Sawicki, R. M., and E. M. Thain. 1961. Chemical and bio- 922 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 55, No.6

logical examination of commercial pyrethrum extracts and their mode of action .. Jour. Agric. Food Chem. for insecticidal constituent's. Jour. Sci. Food Agric., 8(4): 261-6. 12: 137-45. Ward, J. 1953. Separation of the "pJ·rethrins" by displace- Sun, Y-P, and E. R. Johnson. 1960. Synergistic and antag- ment chromatography. Chem. and Indust. .586-7. onistic actions of insecticide-synergist com binations

Infestation of Sweet Corn by the Dusky Sap Beetle, Carpophilus lugubris1

FLOYD P. HARRISON, Department of Entomology, University of Maryland, College Park Downloaded from https://academic.oup.com/jee/article/55/6/919/2207467 by guest on 28 September 2021 ABSTRACT Several facts reported by Connell (1956) indicated that In 1959 and 1960 observat.ions were made on the infestation of some method other than percentage of plants in silk could COl'll plants by the dusky sap beetle, Carpophillls lugllbris possibly be a dependable basis for timing sap beetle sprays l\1:urray, which indicat.e that effectively timed insectieidc treat- and ultimately be of lise in determining whether the ments for control of the sap beet.le probably coincide with the optimum timing of sap beetle sprays coincides with the time when sprays for control of the corn earworm, Heriothis zea optimum t.imingof corn earworlll sprays. (Boddie), should be applied. Adult sap beetles congregate in the Connell stated that sap beetles "feed on pollen when it area of the corn plant t.hat receives most of the spray material begins to ripen, chewing at the tassels to obtain it and when ear-protecting sprays for control of the corn earworm are applied. Sap beetle infestation is increased when other insects later feeding on the quantities that lodge in the leaf injure the corn plant, and t.he adult beetles are attracted to tile axils ... Eggs are laid on the silks, beginning when that damaged sites. portion outside the silk tube has begun to turn brown." The two statements led the author to think that pollina- tion of the corn silks was related in some way with sap Harrison & Ditman (1958, 1960) and Ditman & Harri- beetle infestation, and this could be the key to discovering son (1958) established the timing and spacing of DDT-oil a good basis for timing chemical treatments. It is well emulsion sprays for the most effective control of the corn known that the dusky sap beetle is attracted to ferment- earworm, Heliotkis sea (Boddie), in Maryland. Later ing and decaying plant material. The silk turning brown is research indicated that the addition of an organic-phos- associated with pollination and might well be a good index phol'Us-containing insecticide such as malathion to the of pollination. 'Weatherwax (1923) observed that silk earworm sprays of DDT-oil emulsion would reduce injury continues to grow until it is pollinated, then it stops grow- by the dusky sap beetle, Carpophil1tS lugubris Murray, ing and dies. The author has observed this phenomenon Harrison (1960a).. More recent work has shown that by bagging corn ears beforesilksappeared. Ears so bagged Sevin® (I-naphthyl N-methylcarbamate) and Thio- easily grew fresh, green silks 2 feet long. With the afore- dan® (6,7,8,9,10,10-hexachloro-l,5,5a ,6,9,9a-hexahydro- mentioned facts in mind, the work presented here was 6,9,methano-2,4,3-benzodioxathiepin 3-oxide) are effec- carried out with the hope of determining: (1) if the per- tive in controlling both insects (Harrison 1962). This centage of silks turning brown could be relied upon as a information has encouraged further work to help integrate basis for timing sap beetle sprays; (2) if the distribution of control of corn earworm and dusky sap beetle. There is, adults over the plants would be such that ear sprays could however, no evidence that sap beetle sprays applied with effect any degree of knockdown of adult beetles; (3) the corn earworm sprays are properly timed. extent to which injury by other insects, such as the Euro- A brief review of some of the existing knowledge con- pean corn borer (Ostrinia nubilalis (Hubner» and the cerning both insects will be of help in understanding the corn earworm, might attract adults thereby aggravating reasoning behind the work reported here. When young sap beetle infestations. corn ears first silk, the silk is attractive to the female corn METHoDs.-The methods employed in making these earworm moth (Quaintance & Brues 1905 and Harrison observations were generally the same in both years. 1960b.) Since silking of corn plants in a field proceeds in Approximately one-half acre of the Deep Gold variety of many cases for several days, sometimes for as long as 2 sweet corn was planted for use in the study each season. weeks, one 01' even two applications cannot protect all the The plantings were divided into plots equal in size, each of silks. Therefore, timing of earworm sprays is an important several rows, enough for using one plot each day from the consideration. The relative number of plants in silk offers time silks first appeared until the corn was ready to har- a good means of expressing time in relation to chemical vest. Sixteen plots were used each year. It was necessary treatment. This subject is covered in some detail by to make the observations in different plots every day Harrison & Ditman (1958, 1960). There is no mechanism because the plants were destroyed as observations were or device for basing the time of application of chemicals made. for sap beetle control, nor are there any detailed observa- Every day 100 plants were counted in each plot and tions to indicate whether ear sprays for sap beetle control the percentage of plants in silk was recorded. Then, 25 would adequately cover corn plants to effect sufficient plants were counted and the following information was killing of adults. Whitlaw et al. (1959) demonstrated the recorded for each plant: the number and location of the effectiveness of airplane applications for reducing adult I Scientific Article No. A976, Contribution No. 8858 of tbe Maryland Agricul- populations but not for ground sprays applied to the area tural Experiment Station, Department of Entomology. Accepted for publication of the ear. April ~g, 196~.