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Cuelure, the acetate of raspberry ketone, has been the standard melon fly (Bactrocera cucurbitae) attractant for at least 40 yrs. A closely related compound, raspberry ketone formate, is somewhat more volatile and has been found to be at least 1.7 times more attractive to both sterile and wild melon flies in field tests conducted in Hawaii, consistently outperforming cuelure for periods exceeding one month.

A C18 reversed-phase HPLC method has been developed to analyze the concentration of 2-O-β-d-glycopyranosyl-cucurbitacin E (synonym, elaterinide) in juice or reconstituted residues of juice derived from a bitter mutant of Hawkesbury watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai. The method requires only two steps (homogenation and filtration) for sample preparation prior to column injection and, thus, is amenable to processing large numbers of test samples. Percent elaterinide in juice samples from whole fruit, processed in various ways, ranged from 0.0230 to 0.0808%. Error differences in percent elaterinide for repetitive analyses within the same lot of juice ranged from 1.2 to 5.6%. Keywords: HPLC analysis; corn rootworm; elaterinide; cucurbitacin E glycoside; Hawkesbury watermelon; Citrullus vulgaris Schrad.; Citrullus lanatus (Thunb.) Matsum. & Nakai.

The attraction of male Ceratitis capitata (Wiedemann) to tert-pentyl 4(and 5)-chloro-trans-2-methylcyclohexanecarboxylate (or pentamedlure) was compared to its attraction to trimedlure to establish the suitability of pentamedlure as a possible alternate for trimedlure in applications that use a cotton dental-roll wick dispenser. Results from field tests with released sterile C. capitata showed that pentamedlure, applied to cotton dental roll wicks, was not only comparable to trimedlure in attractiveness but was more persistent. Batch to batch variations in isomer distribution of pentamedlure appeared to have little effect on attraction. Dose-response data showed that pentamedlure, applied at 0.02 and 0.16 ml/wick, initially caught more flies than trimedlure at comparable doses. Moreover, initial catches for pentamedlure for most dosages tested exceeded, but not significantly, initial catches for trimedlure despite a much higher load (2 ml/wick). Trimedlure initial catches within a natural population of wild C. capitata were significantly higher than pentamedlure catches at a comparable dosage (0.2 ml lure/wick). However, pentamedlure-treated wicks were 2 to 3 times more persistent than wicks treated with trimedlure.

Fractions obtained by open-column flash chromatography of a crude methanolic extract of the rind of a bitter mutant of Hawkesbury watermelon, Citrullus vulgaris Schrad, were further purified by preparative high-performance liquid chromatography (HPLC) to isolate chemical component(s) that elicit a visitation/feeding stimulancy response to the southern corn rootworm, Diabrotica undecimpunctata howardi Barber. Activity of chromatographic fractions were followed with a laboratory bioassay involving total insect-response counts. The chemical structure of the most active component in C. vulgaris was confirmed by chemical ionization mass spectrometry and proton nuclear magnetic resonance spectroscopy to be cucurbitacin-E glycoside. Two other cucurbitacin-like compounds were isolated and structures for them postulated. A procedure to prepare a crude, biologically active, extract of C. vulgaris is reported. Dose-response data for the crude extract in laboratory tests against two diabroticite beetles D. undecimpunctata howardi and D. virgifera virgifera LeConte are also reported.

Laboratory and field-cage experiments evaluated the efficacy of a water-soluble bait for control of adult diabroticites. The bait was composed of a water-soluble feeding stimulant derived from a bitter mutant of Hawkesbury watermelon (Citrullus vulgaris Schrad), a dye toxin (phloxine B: D & C Red Dye No. 28), and a modified food starch (Mira Sperse 626). In the laboratory, southern corn rootworm, Diabrotica undecimpunctata howardi Barber adults, were exposed to separate bait components and combinations thereof. Eighty percent of adults exposed to the complete bait formulation died within 24 h. Adult mortality increased with higher concentrations of dye and increasing light intensity. Incorporation of the feeding stimulant with the dye reduced the lethal time. The complete bait was most active in sunlight, killing 90% adults in 1 h. Under fluorescent lights, the LT90 for the adults was 48 h. In field cages, using corn plants treated with the bait formulation, numbers of live western corn rootworm, D. virgifera virgifera LeConte, adults were reduced by 80% compared with the untreated control. This new water soluble toxic bait appears suitable for testing on a larger scale in the field as a component of an IPM program for corn rootworm pests.

Reports questioning the safety of methyl eugenol (1,2-dimethoxy-4-[2-propenyl] benzene) stimulated us to develop and test synthetic analogues that may be used as alternative attractants for oriental fruit fly, Bactrocera dorsalis (Hendel), males. Attraction to one propyl-substituted and six monofluorine-substituted methyl eugenol analogues were compared with attraction to methyl eugenol in field bioassays with both laboratory-reared and wild oriental fruit fly males. The attractiveness of the test compounds to oriental fruit fly males was compared using two parameters: number of adults caught per trap and number of adults caught per mg of compounds released in traps. Based on these two parameters (E)-1,2-dimethoxy-4-(3-fiuoro-2-propenyl)benzene was consistently as attractive as methyl eugenol to both laboratory-reared and wild oriental fruit fly males. With further studies to determine optimum release rates, (E)-1,2-dimethoxy-4-(3-fluoro-2-propenyl)benzene may potentially replace methyl eugenol for survey, detection, delimitation of infestation and eradication of oriental fruit fly populations.

Crystals of 1-(2,6-difluorobenzoyl)-5-(4-chlorophenyl)biuret (BFB), C15H10N3O3F2Cl, were grown by evaporation from an acetonitrile solution. Two polymorphs were obtained. The first polymorph (BFB1) crystallized in the monoclinic space group P21/c (Z = 4) with unit cell a = 13.021(3), b = 5.293(1), c = 21.199(6) A, and β = 97.34(2)°. The second polymorph (BFB2) crystallized in the orthorhombic space group P 212121 (Z = 8) with a = 10.513(1), b = 10.806(1), and c = 26.685(1) A. The results of crystallographic and molecular modeling studies on BFB were in good agreement. The compound has an extended conformation with the benzene rings coplanar and the intervening –CONHCONHCONH– moiety rotated out of the plane due to steric effects from the two fluorine atoms.

A chicken feather hydrolysate prepared by heating feathers with 6N hydrochloric acid was highly attractive to the West Indian fruit fly, Anastrepha obliqua (Macquart), and the Mexican fruit fly, Anastrepha ludens (Loew). In cage-top laboratory tests to determine the influence of pH on attraction, chicken feather hydrolysate, adjusted to pH 8.0, elicited the greatest response from adult A. obliqua; the attraction response was more than twice that observed for a 10% NuLure® (Miller Chemical and Fertilizer Corp., Hanover, PA) standard. Neutral or slightly acidic preparations of chicken feather hydrolysate were less effective. While A. ludens was less attractive in the laboratory tests to a 25% chicken feather hydrolysate than a 10% NuLure standard, A. obliqua appeared slightly more attracted to the hydrolysate than NuLure, but not significantly. In a 5-day field test using sterile released A. ludens, 4.5% chicken feather hydrolysate, adjusted to pH 8.0, caught almost 2.5 times more flies than 10% NuLure. Twenty-three volatile compounds that emanated from chicken feather hydrolysate were identified by headspace analysis using GC-MS and GC retention index comparison techniques. Among the volatiles were 7 ketones, 6 alcohols, 2 aldehydes, 2 chlorocarbons and 2 furans. At pH 8.0, the five most abundant compounds in decreasing order were 4-methyl-2-pentanone (76.3%), 4-methyl-2-pentanol (16.5%), 1-hexanol (3.1%), 1-heptanol (0.81%) and 2-butoxyethanol (0.64%).

A dynamic headspace analysis was performed on the volatile components of E802 Mazoferm steepwater, a condensed fermented corn extractive, that is highly attractive in laboratory and field tests to adult Mexican fruit flies, Anastrepha ludens (Loew). Chemical characterization was accomplished by capillary GC and GC/MS methods. A total of 19 compounds were identified, and these were comprised of 6 alcohols, 5 esters, 3 aldehydes, 2 lactones, an alkyl furan, an acid, and a trisulfide. When E802 Mazoferm steepwater was analyzed at pH 3.9, the five most abundant compounds in the volatiles (in descending order) were 3-methyl-1-butanol (43.9%), ethyl lactate (23.7%), ethanol (15.4%), 2-methyl-1-propanol (12.8%), and ethyl acetate (0.71%). At pH 8.0, the same five compounds were again the most abundant. Except for a reversal in order for the first two compounds, the order was the same: ethyl lactate (37.3%), 3-methyl-1-butanol (32.5%), ethanol (14.2%), 2-methyl-1-propanol (10.4%), and ethyl acetate (3.09%). Keyw...

Several amines were tested alone and in combination with AMPu, an attractant mixture containing ammonium bicarbonate or ammonium carbonate, methylamine hydrochloride, and putrescine, for attractiveness to Mexican fruit flies (Anastrepha ludens Loew). In laboratory bioassay, 1-pyrroline, 3-pyrroline, 2-(methylamino)ethanol, spermidine, spermine, and indole-3-acetic acid were significantly more attractive than solvent controls. In orchard tests, traps baited with combinations of AMPu with dimethylamine hydrochloride, ethylamine, 2,5-dimethylpyrazine, or pyrrolidine captured fewer flies than traps baited with AMPu alone. Traps containing AMPu plus additional ammonium bicarbonate were much less attractive than AMPu alone. Combinations of AMPu with 1-pyrroline were about 50% more attractive than AMPu alone to both males and females. Combinations of AMPu with 3-pyrroline were not significantly more attractive than AMPu alone.

Chitin-synthesis inhibitory effects of nine l-benzoyl-5-phenyl-biurets and six l-benzoyl-5-phenyl-4-thiobiurets were determined in an in vitro assay using male pharate adult claspers of the European corn borer, Ostrinia nubilalis (Hübner). Incorporation of labeled N-acetylglucosamine into the clasper tissue was effectively inhibited by the benzoylbiurets (IC50 values ranged from 0.032 to 8.2 ppm). Quantitative structure-activity relationships of the benzoylbiurets were analyzed by linear regression analysis. The analysis used yellowfever mosquito (Aedes aegypti (L.)) adult emergence data (LC50 values) and in vitro chitin-synthesis inhibition data (IC50 values) as biological endpoints and a set of physicochemical parameters (independent variables) of the para substituent of the anilide moiety. Stepwise regression analysis of the in vivo data provided a significant four-parameter equation involving Hammett σp and Hansch-Fujita π constants, and two indicator variables. Analysis of the in vitro chitin-synthesis inhibition data yielded a significant two-parameter equation incorporating σp and an indicator variable. In vitro larvicidal activity against A. aegypti and the house fly (Musca domestica L.) was enhanced by electron-withdrawing and lipophilic substituents in the para position of the anilide moiety. In contrast, in vitro chitin-synthesis inhibition was favored by electron-donating substituents. It was suggested that the equations derived from in vivo activity data describe mainly pharmacokinetic processes such as transport and metabolism. Structural requirements for intrinsic activity of the benzoylbiurets at the putative receptor site were better represented by the equation derived from the in vitro chitin-synthesis inhibition data.

Methyl eugenol, is a commercially used fruit fly attractant and a suspected carcinogen. Several phenylpropenes, including methyl eugenol and the known carcinogen safrole, score negative in the Salmonella assay but score positive in the yeast DEL assay that selects for intrachromosomal recombination events in the yeast Saccharomyces cerevisiae. In an attempt to dissociate the beneficial properties of methyl eugenol from its genotoxic properties, saturated or fluorinated analogs were evaluated for their ability to induce intrachromosomal (DEL) recombination in yeast. Field tests have previously shown that all of the analogs used have appreciable properties as fruit fly attractants. The analogs 1,2-dimethoxy-4-ethylbenzene, 1,2-dimethoxy-4-(2-fluoro-2-propenyl)benzene, 1,2-dimethoxy-4-(2-fluoroethyl)benzene and 1,2-dimethoxy-4-(3-fluoro-2-propenyl)benzene all showed reduced toxicity and reduced recombinagenicity in yeast compared to methyl eugenol. These results confirm the validity of fluorination and/or removal of the 2-propenyl moiety in reducing the toxicity and recombinagenicity of methyl eugenol derivatives.

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is a major pest of fruits and vegetables in the world but, through an extensive trapping program, the continental United States has remained free of established populations. These traps are baited with 2 g of trimedlure which is highly attractive to the male flies. This study contrasts the effectiveness of trimedlure and a new attractant, ceralure, which is an iodo-analog of trimedlure. Field tests in Hawaii using released sterile flies showed that the most attractive B1 isomer of ceralure caught 2 to 3 times as many male flies per mg as did the most attractive C isomer of trimedlure.

(E)-8-Acetoxy-6-methyl-6-octen-2-one, a key intermediate for the male-produced sex pheromones of the Mexican and Caribbean fruit fly, was synthesized stereospecifically in five steps with an overall yield of 50%.

Larvicidal activity of a congeneric set of N-2-halo- (and 2,6-dihalo) benzoyl-N-phenylureas were determined in in vivo tests against the lesser mealworm, Alphitobius diaperinus (Panzer). Substituent modifications were made in both the benzoyl and anilide portions of the molecule. Linear regression analysis was used to derive quantitative structure-activity relationships (QSAR) from LC50 and LC99 values and a series of physicochemical substituent parameters. The analysis resulted in two significant single parameter regression equations selecting Hammett σp constant as the only relevant chemical descriptor and rejecting the other descriptors as insignificant. Penfluron and 2,6-difluoro-N-[[[4-(trifluoromethoxy) phenyl]amino]carbonyl]benzamide were potent larvicides in these tests and exceeded the effectiveness of diflubenzuron and triflumuron.

An analysis was performed to identify the volatile components of a supernatant derived from a bacterial (Klebsiella pneumoniae, ATCC 13883, American Type Culture Collection) fermentation of a trypticase soy broth. The bacteria-produced supernatant (BPS) was comparable to a 30% solution of NuLure in attractiveness to mixed sexes of adult Mexican fruit flies, Anastrepha ludens (Loew), in a laboratory bioassay. The volatile components of BPS, most resulting from bacterial metabolism, were identified by a combination of capillary GC and GC-MS techniques. A total of 21 compounds were identified, including 7 alcohols (2 sulfur containing), 8 alkyl-substituted pyrazines, 2 ketones, 2 acids, 1 ketoalcohol, and phenol. The five most abundant compounds, in decreasing order of abundance, were 3-methyl-1-butanol, phenethyl alcohol, 2,5-dimethylpyrazine, 2-methyl-1-propanol, and 3-(methylthio)-1-propanol. One or more unidentified, low molecular weight amines were also present in the mixture of volatiles.

KK-42 (1-benzyl-5-[(E)-2,6-dimethyl-1,5-heptadienyl]imidazole), administered by feeding, delayed the growth and development of nondiapause-bound and diapause-bound Ostrinia nubilalis larvae and increased the length of the instar. At doses of 80–240 ppm, 62–100% of nondiapause-bound fourth instars precociously pupated or remained as fourth instars, while 52–100% of diapause-bound fourth instars did not molt to the fifth instar. Injection of these nondiapause- and diapause-bound KK-42-fed fourth instars with ecdysone elicited a molt and resulted in the production of larval-pupal intermediates. When mature fourth instar controls were similarly injected, they molted into normal fifth instars. These results support the view that KK-42 delays/inhibits ecdysteroid production. Both eupyrene and apyrene spermiogenesis were prematurely initiated in nondiapause-bound fourth instars that were fed on medium containing 160 ppm KK-42. Fenoxycarb, a potent juvenile hormone mimic, rescued nondiapause-bound fourth instars from precocious pupation. All fenoxycarbtreated larvae either molted to the fifth instar or remained as fourth instars and eventually died. These results support the view that treatment with KK-42 inhibits JH production. When KK-42 treatment was begun in the third instar, a considerable number of nondiapause-bound and some diapause-bound third instars precociously molted to the fifth instar. There was a correlation between weight and the incidence of precocious molting in that third instars destined to skip the fourth instar attained a weight, as pharate fifth instars, of two to three times more than pharate fourth instar controls. Similarly, fourth instars that were destined to undergo precocious pupation attained a weight, as pharate pupae, that was approximately two times more than pharate fifth instar controls. More potent analogues of KK-42 may prove useful in controlling populations of 0. nubilalis by interfering with their growth, development, and metamorphosis. © 1995 Witey-Liss, Inc.1

Sixty-eight structural variants of trimedlure, tert- butyl 4(and 5)-chloro-2-methylcyclohexane-l-carboxylate (TML), the male attractant for the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were evaluated as attractants to determine the importance of the substituents to the attractiveness of TML. The l- tert -butyl carboxylate and 4(and 5)-chloro substituents in TML can be replaced selectively with no significant reduction in attractiveness. However, the 2-methyl substituent appears to be very important for high levels of attraction. Thirteen halogen analogs of TML showed initial attractancy that was not significantly different from that of TML. In addition, nine of the halogen analogs were as persistent or more persistent than TML at high levels of attractiveness. In a longer tenn (15 d) follow-up test with 14 promising lures, no significant difference was found between the attractiveness of four of the lures and a freshly baited TML wick after 4 d, by which time an aged TML wick had become depleted of lure. Of the four lures, trifluoroethyl 4(and 5)-iodo-trans-2-methylcyclohexane-I-carboxylate was especially attractive through 4 d of the test, during which time it was the top-ranked lure. Ethyl 4(and 5)-bromo- trans -2-methylcyclohexane-l-carboxylate were very persistent lures, continuing to catch moderate number of C. capitata through days 11 and 15, respectively.

A series of one- and two-dimensional NMR experiments were used to confirm structures of the four racemic trans isomers of ceralure, ethyl 4-(or 5)-iodo-trans-2-methylcyclohexane-1-carboxylate, a synthetic attractant for the male Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Proton and carbon assignments were made on the basis NMR data obtained from 2D chemical shift correlation maps, attached proton tests, and 2D- 1 H homonuclear correlation spectroscopy. Assignments of configuration and conformation, based on NMR, for the four trans isomers of ceralure (A, B 1 , B 2 , and C) were consistent with assignments previously derived from a comparison of the gas chromatographic elution behavior of the trans isomers of ceralure and the trans isomer of trimedlure, 1,1-dimethylethyl 4-(or 5)-chloro-trans-2-methylcyclohexane-1-carboxylate

Eight of 44 selected analogs of veratrole showed promise as attractants for male, oriental fruit fly, Dacus dorsalis Hendel, in week-long field tests when compared with a standard methyl eugenol (ME) lure. 4-Propyl- and 4(and 5)-allyl-2-ethoxy-1-methoxybenzene were the most effective of the eight promising lures showing high levels of initial and persistent attraction. 4-Ethyl-2-ethoxy-1-methoxybenzene showed a high level of initial attraction but lacked persistence as did its corresponding dimethoxy analog. High levels of attractancy demonstrated by several analogs evaluated in this study suggest that they could serve as potential alternatives to ME, if a critical need arises and their toxicity is acceptable. Despite previous studies showing that 889 chemicals were attractive to D. dorsalis in olfactometer tests, only three of the chemicals showed promise in the field.

A capillary GC method has been developed to analyze laboratory or commercial samples of the medfly attractant ceralure [ethyl 4- (and 5-)iodo-trans-2-methylcyclohexane-1-carboxylate]. The method utilizes a specially prepared fused-silica column with a bonded phenyl-methyl polysiloxane liquid phase. Baseline separation was achieved for three of the four trans-ceralure isomers. Difficulties encountered with other columns investigated are also discussed.

A general synthetic approach to various catechol derivatives was developed using a copper-catalyzed cross-coupling reaction of 1,2-dimethoxy-4-brornomethyl, 1-ethoxy-2-methoxy-4-bromomethyl- and 2-ethoxy-1-methoxy-4-bromomethylbenzenes with Grignard reagents. Dilithium tetrachlorocuprate was an acceptable catalyst in the dimethoxy series, whereas copper(I) iodide in THF-HMPA was a superior catalyst in all cases due to decreased side reactions, i.e., reduction and reductive coupling. Methyl-substituted analogs of methyl eugenol, a potent attractant of Oriental fruit fly,Dacus dorsalis Hendel, were synthesized by this method and evaluated for attractancy in field tests.

CIC-4 (1,1,4,5,6,7,8,8a-octahydro-3H-2-benzopyran-3-one) is a fused bicyclic lactone which acts as a non-contact insect repellent for Aedes aegypti at 1% concentration in 95% aqueous ethanol when applied topically to rhesus monkeys. Chromatographic and spectroscopic analyses of a synthetic sample indicated the presence of cis-and trans-fused isomers. To supply each isomer for the assessment of mosquito repellent efficacy on humans, we developed a semi-preparative high-performance liquid chromatographic separation technique for the isomer separation. A column of 5-μm silica was used for isolating milligram quantities of each isomer. By this method, each isomer was obtained in > 95% gas-liquid chromatographic (GLC)-purity for biological evaluation. Supporting GLC and electron impact and chemical ionization gas chromatography-mass spectrometric data are also presented for each isomer. Biological evaluation on the human arm using Anopheles quadrimaculatus, Aedes aegypti, and Anopheles albimanus as the test species was effective in determining relative repellency to the standard N,N-diethyl-3-methyl-benzamide

Extracts of brains, subesophageal ganglia, Malpighian tubules, mandibular glands, proctodaea, salivary glands, testes, and fat body from mature fifth-stage European corn borer larvae contain a 3-oxoecdysteroid 3β-reductase that converts 3-dehydroecdysone to an RIA-detectable ecdysteroid that has the same retention time (on HPLC and TLC) as ecdysone. Enzyme activity is destroyed by boiling, exposure to organic solvents, and treatment with trypsin. The reductase has a molecular weight in the range of 24–37 kD and is dependent upon the presence of NADPH for activity. Under the conditions utilized here, subesophageal ganglia, proctodaea, and brain extracts exhibited the highest specific activity; mandibular glands, testes, salivary glands, and Malpighian tubules had moderate specific activity; and fat body had the least. Based on total organ activity, however, fat body and salivary glands had the greates activity; testes, Malpighian tubules, mandibular glands, and proctodaeum had moderate activity; and brain and subesophageal ganglion had the least.

Ammonium acetate was more attractive than other ammonium salts to Mexican fruit flies (Anastrepha ludens) in an orchard test. We hypothesized that acetic acid enhanced the attractiveness of ammonia in the orchard test and that acetic acid may similarly enhance attractiveness of AMPu, an attractant consisting of a mixture of ammonium bicarbonate or ammonium carbonate, methylamine HCl, and putrescine. In laboratory experiments, acetic acid was attractive to flies deprived of either yeast hydrolysate or both sugar and yeast hydrolysate but not to flies fed both sugar and yeast hydrolysate. AMPu/acetic acid combinations were more attractive than AMPu alone to flies deprived of both sugar and yeast hydrolysate but not to flies fed sugar, regardless of yeast hydrolysate deprivation status. Acetic acid is the first attractant found that has become more attractive with both sugar and protein deprivation in studies withA. ludens. It is also the first that has enhanced the attractiveness of another attractant type. In orchard tests, yellow sticky panels baited with either AMPu or 17 mg of acetic acid were at least six times more attractive than unbaited panels. However, panels baited with both acetic acid (17–68 mg) and AMPu were less attractive than AMPu alone. These results differed from the laboratory data in which combinations were never less attractive than AMPu alone.

Differences in attractiveness of four individualtrans isomers of ceralure (CRL) [ethyl 4- (and 5-) iodo-trans-2-methylcyclohexane-1-carboxylate] for male Mediterranean fruit fly,Ceratitis capitata (Wiedemann), were investigated. One of the isomers, CRL-B1 (ethylcis-5-iodo-trans-2-methylcyclohexane-1-carboxylate) was significantly superior to the three othertrans-CRL isomers, CRL, trimedlure (TML) [1,1-dimethylethyl 4- (and 5-) chloro-trans-2-methylcyclohexane-1-carboxylate], and TML-C (1,1-dimethylethyl-cis-4-chloro-trans-2-methylcyclohexane-1-carboxylate) on an equal weight basis.

Our present knowledge regarding the hormonal control of insect development and diapause is based upon studies involving post-embryonic stages, i.e., late larval, pupal and adult forms. Except for a single species, the commercial silkworm, Bombyx mori, which enters diapause at a very early embryonic stage, little is known about the endocrinology of embryonic development in lepidopterous insects. The univoltine gypsy moth, Lymantria dispar enters a prolonged obligatory diapause that occurs in late embryonic development after becoming a mature and fully differentiated pharate larva (Leonard, 1968). Little or no information is available on the endocrine regulation of diapause occurring at such a late stage of embryonic development. Thus the main purpose of the present study was to obtain fundamental information on the metabolic activity as well as the ecdysteroid and prothoracicotropic (PITH) hormone titers during the course of embryogenesis and entry into diapause. The rationale for selecting this approach was to test the hypothesis that late embryonic diapause may be regulated by the brain-prothoracic gland system and therefore could be associated with a failure of synthesis or secretion of PITH and development promoting ecdysteriod hormones in a manner similar to that found in larval and pupal diapause in post-embryonic stages (see Denlinger, 1984).

House fly oostatic hormone (OH) was first reported 21 years ago and postulated to be involved in a humoral feedback mechanism controlling cyclical production of eggs (Adams et al., 1968; Adams, 1981). Active OH extracts have been prepared from mature adult ovaries, abdomens, or whole bodies (Adams, et al., 1968; Adams 1977; Kelly et al., 1984a). While extensive studies to elucidate oostatic mechanisms have been conducted in Rhodnius prolixus, Diploptera punctata, Aedes aegypti, Aedes atropalpus and Musca domestica information on the chemical nature of these factors has been reported in only two of these species (R. prolixus Liu and Davey, 1974; and A. aegypti Borovsky, 1985).

A simple and convenient gas-liquid chromatographic procedure involving electron capture detection is described for determining diflubenzuron (N- [[(4-chlorophenyl) amino] carbonyl] - 2,6-difluorobenzamide) in pond water and for determining the uptake of penfluron (trifluoromethyl analog of diflubenzuron) by boll weevils sexually sterilized by this compound. Both compounds were quantitatively converted to their respective N-(trifluoroacetyl) anilines by treatment with trifluoroacetic anhydride and pyridine in benzene at 50–60 °C. In boll weevil analyses, the procedure was quantitative for penfluron at concentrations involving microgram quantities (10–35 ≧g/weevil) without the necessity of a cleanup step. However, at submicrogram quantities, background interference necessitated a thin layer chromatographic cleanup prior to derivatization. This modification enabled the determination of 100 ng/ weevil. Analysis for diflubenzuron in natural pond water gave excellent results. For example, diflubenzuron at 2, 0.2, and 0.02 ppm in pond water was recovered at 95, 82, and 98%, respectively. A mechanism describing the reaction is proposed.

In laboratory tests, diflubenzuron ( N -[[(4-chlorophenyl)amino] carbonyl]-2,6-difluorobenzamide) (AB-29054), EL-494 ( N -[[(5-(4-bromophenyl)-6-methyl-2-pyrazinyl]amino]carbonyl]-2,6-dichlorobenzamide), EL-588 (2,6-dichloro- N -[[[5-(4-chlorophenyl)-2-pyrazinyl]amino]carbonyl-]benzamide), A13-63220 ( N -[[(4-bromophenyl)amino]carbonyl]-2,6-difluorobenzamide), and A13-63223 (2,6-difluoro- N -[[(4-(trifluoromethyl)phenyl]amino]carbonyl]benzamide) prevented development of adult pink bollworms, Pectinophora gossypiella (Saunders) when they were fed in larval diet at 1–10 ppm. Contact experiments with adult moths indicated little activity at up to 18 mg/cm2 except for AI3-3220 and AI3-63223 which caused significant mortality after a 1-wk exposure to treated cage surfaces. Diflubenzuron and EL-494 were tested for systemic activity by treating foliage of cotton plants at rates up to 15.2 mg/plant without effect on subsequent development of the pink bollworm. A further test in field cages using the 2 compounds at a rate of 0.11 kg/ha indicated that diflubenzuron was superior to EL-494 for control of the cotton leafperforator, Bucculatrix thurberiella Busck, but neither compound had any activity against the pink bollworm.

Heliothis virescens maintained on a diet containing 50 ppm of thiazolylurea (5-[[[2-thiazolylamino]amino]carbonyl]-l,3-benzenedicarboxylic acid dimethyl ester) showed symptoms of juvenile hormone overdose in the last larval instar. Increases in development time and weight, as well as larval color changes, were similar in animals fed thiazolylurea or topically treated with the juvenile hormone mimic methoprene. The juvenile hormone esterase titer profile in hernolymph of animals fed thiazolylurea was much broader than in controls, and peaked 2 days later than in controls; the premolt ecdysteroid peak in hemolymph of animals fed thiazolylurea appeared 2 days earlier than in controls. These events are characteristic of high hemolymph JH titers throughout the last larval instar.

Toxicity was determined for 15 acaricides against a laboratory strain of northern fowl mites,Ornithonyssus sylviarum (Canestrini and Fanzago). Adult females were exposed to residues on filter paper for 24 h. Three organophosphorous compounds (monocrotophos, cythioate, and famphur) were more toxic to the northern fowl mite than was carbaryl, the most commonly used pesticide in the poultry industry. The other tested compounds were less toxic to the mite than was carbaryl. Four of these, not used previously for northern fowl mite control, had low LC50's for northern fowl mites: aldicarb (0.46); pirimiphos-methyl (0.73); exo, exo-2,8-dichloro-4-thiatricyclo [3.2.1.03.6]octane-4-oxide (AI3-63182) (0.87); and diazinon (2.48).

[1-(2-Pyridinyl)ethylidene]hydrazide of 1-pyrrolidinecarbothioic acid (AI3-63967) and seven similar thiosemicarbazones applied topically to Oncopeltus fasciatus were toxic or prevented ecdysis in fifth instars without the appearance of supernumerary nymphs. Treatments with AI3-63967 did not affect weight gain of the nymphs but delayed by 2 days the rise in hemolymph ecdysteroids and reduced their maximal titer by ca. 40%. Restoration of the ecdysteroid titer by injections of makisterone A or 20-hydroxyecdysone did not prevent the molting aberrations. Treated fourth instars exhibited incomplete ecdysis followed by death and treated adults died within 9 days post-treatment. Apparently, this group of thiosemicarbazones acts by a mechanism different from that of juvenile hormone mimics or chitin synthesis inhibitors.

Prolongation of development caused size and weight increases in both larvae and pupae surviving treatment. Thiazolylurea 1 elicited similar growth and development effects in the tobacco budworm but was not as toxic to larvae. Structure-activity relationships were determined by testing 37 analogues of 1 against the fall armyworm. Compound 7, the diisopropyl ester analogue of 1, was the most effective compound against the fall armyworm, with growth-regulating effects observed at a dietary concentration as low as 1 ppm

One hundred ten substituted melamines were tested as chemosterilants against Musca domestica L. Melamines that were sufficiently basic to form stable salts were tested as hydrochlorides. Fifty-five effectively inhibited hatch or pupation. The most effective inhibitors of hatch were tri- to hexasubstituted methylmelamines. Melamines without methyl groups or methylmelamines containing large alkyl, aryl, or other bulky groups were ineffective against males. As a rule, compounds that affected hatch when both sexes were treated were also effective when only males were treated. Melamines that had 2 free amino groups and small cyclic substituents on the 3rd exocyclic nitrogen were generally without effect on hatch, but they inhibited pupation of larvae produced by treated females. The inhibitors of pupation were ineffective in sterilizing males. All compounds were evaluated in 2 diets: sugar and fly food. The effects of the 2 foods and of the 2 forms of the compounds were often large, but only relatively uniform series of results were considered in structure-activity correlations.

The chemosterilant hemel is metabolized by male Musca domestica L. to lower methylmelamines and to other, possibly acyclic, products. The methylmelamines isolated from treated flies and from their excreta were identified as: pentamethylmelamine, N2, N2, N4, N6 -tetramethylmelamine, N2, N4, N6 -trimethylmelamine, and N2, N2, N4 -trimethylmela. mine. Mono- and dimethylmelamines were not detected and unchanged hemel was found only in the flies. In 24 hours, the treated flies converted about 11% of the methyl carbons of hemel to respiratory CO2. Hemel uniformly labeled with C14 in the methyl groups was synthesized and used in the initial experiments, but the identity of the methylmelamine metabolites was confirmed by isolating them and comparing them with synthetic reference compounds. Also, the sterilizing activity of all trio, tetra, and pentamethylmelamines was determined. The most active methyl melamine, N2, N2, N4, N4 -tetramethylmelamine, was not found in the treated flies or in their excreta.

Chemosterilants derived from s -triazine comprise aziridinyl alkylating agents, melamines, and 6-substituted 2,4-diamino- s -triazines. All are effective in Musca domestica L., but the aziridinyl triazines and melamines sterilize both sexes, whereas the diaminotriazines sterilize only females. Tests with 25 diaminotriazines revealed characteristic effects on the late stages of embryogenesis that were not induced by the other classes of triazines or by other types of chemosterilants. Generally, oviposition of flies treated with lowest effective dose of diaminotriazines was normal, and egg hatch was reduced only slightly; however most or all the larvae died before pupating. As an additive to the flies’ diet, 2,4-diamino-6-(2-furyl) s triazine induced such effects at concentrations as low as 2.5 ppm.

When mixed sexes of 1-, to 2 day-old adult Musca Autumnalis De Geer were fed diflubenzuron ( N -[[ (4-chlorophenyl) amino]carbonyl]-2,6-difluorobenzamide) in a diet or were exposed to diflubenzuron by surface contact, egg hatch was severely inhibited. In 3 treatments, untreated females produced few viable eggs when crossed with treated males. Optimum inhibition of egg hatch occurred when either sex was exposed for 15 min to a surface coated with a diflubenzuron dust (25%-WP). Three closely related analogues of diflubenzuron (AI3-63219, AI3-63220, and AI3-63223) also inhibited hatch but none was significantly better than diflubenzuron.

Female Anthonomus grandis Boheman are effectively sterilized for as long as 8 wk when dipped in acetone solutions of A13-63223 [1-(2,6-difluorobenzoyl)-3-[4-(trifluoromethyl) phenyl]urea]. This compound is superior to difiubenzuron from which recovery of fertility occurs after 2–3 weeks. Considerable reduction of reproduction also occurs with male boll weevils similarly treated with A13-63223.

2,4-bis(1,1-dimethylethyl)-6-[(4-methoxyphenyl)methyl] phenol(AI3-70691) prevented all reproduction by female Musca domestica L. when fed a 1% concentration in the diet, injected at a rate of 5 μg/female or treated topically at a rate of 20 μg/female. However, sterilizing effects were impermanent. Male fertility was affected only slightly when the compound was fed at 1–2% concentrations. 5-ethoxy-6-[1-(4-methoxyphenyl)-ethyl]-1,3-benzodioxole(AI3-53060) was likewise effective when females were injected with a dose of 10 μg/female or fed a diet containing 0.1 % of the compound. At nontoxic doses, no sterility was induced in males by feeding or injection.