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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.

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.

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%).

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.

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.

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.