Barbara D. Dueben

Identification of sex pheromone produced by female sweetpotato weevil,Cylas formicarius elegantulus (Summers)

A sex pheromone of the sweetpotato weevil,Cylas formicarius elegantulus (Summers), was obtained from collections of volatiles from virgin females, and pheromone was isolated by means of liquid and gas chromatography. The purification procedure was monitored by quantitative laboratory and field bioassays and the compound was identified as (Z)-3-dodecen-1-ol (E)-2-butenoate by means of spectroscopic and microchemical methods. Synthesis, followed by laboratory and field bioassays, showed that the biological activity of the synthetic material was qualitatively and quantitatively indistinguishable from that of the purified natural product.

Analysis, synthesis, formulation, and field testing of three major components of male mediterranean fruit fly pheromone

Three major components, ethyi-(E)-3-octenoate, geranyl acetate, and (E,E)-α-farnesene, emitted as volatiles by laboratory-reared and wild male medflies were collected and analyzed qualitatively and quantitatively. Peak emission of these compounds occurred during the third to fifth hours of the photophase and differences were observed in the ratios of the three components emitted by male laboratory-reared and wild flies. These three compounds were synthesized, and a method was developed to formulate a synthetic blend that released the compounds in a ratio similar to that emitted by wild male medflies. Attractiveness of the blend to female medflies was demonstrated under field conditions by comparing trap catches. Black spherical traps, baited with the synthetic blend to release 1.6 male equivalents, caught significantly more females than blank traps and traps from which the blend released was 0.3, 3.2 or 6.4 male equivalents.

Attraction of 3-methyl-1-butanol and ammonia identified from Enterobacter agglomerans to Anastrepha suspensa

Tests demonstrated that volatile chemicals emitted from Enterobacter agglomerans, a bacterium that has been isolated from adults as well as fruit infested with larvae of the Caribbean fruit fly, Anastrepha suspensa (Loew) and other pest fruit flies, are attractive to female A. suspensa in laboratory bioassays. 3-Methyl-1-butanol and ammonia were identified as the two primary volatile chemicals released from active cultures of E. agglomerans. No 3-methyl-1-butanol and little ammonia (16.0 μg/hr) are released from sterile tryptic soy agar plates. E. agglomerans-inoculated tryptic soy agar plates, however, released an average of 1.5 ± 0.53 μg/hr 3-methyl-1-butanol and 332.9 ± 239.16 μg/hr ammonia after 24 hr of growth. 3-Methyl-1-butanol lures were formulated in a membrane-based system to provide a constant release rate of synthetic chemical. Release rates ranged from 0.046 ± 0.007 to 12.16 ± 2.76 μg/hr. In laboratory tests, equal numbers of females were captured in response to ammonium carbonate lures that released ammonia at the rate of 100 μg/hr and to 3-methyl-1-butanol lures that released 12.16 ± 2.756 μg/hr of synthetic material. The combination of the two lures was more attractive than ammonia alone. Availability of lures formulated for a range of 3-methyl-1-butanol release rates will facilitate field tests of this putative microbial attractant and may lead to a better understanding of the role of bacteria in the ecology of pest fruit flies.

Effects of host plant,Gossypium hirsutum L., on sexual attraction of cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae).

Unmated female or male cabbage looper moths,Trichoplusia ni (Hübner), were attracted more often in a flight tunnel to a cage with moths of the opposite sex and a bouquet of cotton foliage. Increased sexual attractiveness of females with plants may be a result of stimulation of pheromone release in response to plant odor, since more males were attracted when odor of cotton foliage was passed over females than when odor of females was passed over cotton foliage before venting into the flight tunnel. Increased sexual attractiveness of males with plants is due in part to host odor enhancement of female attraction to male pheromone, since more females were attracted to synthetic male pheromone (a blend of enantiomers of linalool and isomers of cresol) and a cotton leaf extract than were attracted to male pheromone alone. A short synthesis procedure was developed for (S)-(+)-linalool, the major component of the male sex pheromone, isolated from hair pencils, used in these tests.

EFFECTS OF SUCROSE IN ADULT DIET ON MORTALITY OF MALES OF ANASTREPHA SUSPENSA (DIPTERA: TEPHRITIDAE)

Abstract Survival of adult male Caribbean fruit flies, Anastrepha suspense (Loew) fed sucrose and protein in the form of hydrolyzed brewers yeast was studied under greenhouse conditions. Flies fed either a 3:1 mixture of sucrose and protein (optimal) or just sugar from the day of adult eclosion showed no appreciable mortality during the 14-day test period. However, flies fed just protein, or those that were not provided with sugar or protein showed rapid rates of mortality, with 50% mortality occurring at 1.87 and 1.53 days, respectively, and 95% mortality occurring at 2.8 and 2.5 days. Switching flies from the optimal diet to either the protein-only diet or nothing at 7 or 11 days after emergence resulted in values of 50% and 95% mortality, respectively, that were similar to those for flies reared from eclosion on either just protein or nothing. No significant mortality occurred among males maintained on the optimal or sugar-only diets or when flies were shifted from the optimal diet to only sugar at either day 7 or 11 after emergence. These data demonstrate that the flies have an absolute requirement for carbohydrate in the adult diet. Additionally, the results indicate that the flies are incapable of converting of amino acids from protein hydrolysate into precursors useful for generating metabolic energy in sufficient amounts to sustain life.

Attraction of Anastrepha suspensa (Diptera:Tephritidae) to Volatiles from Avian Fecal Material

Flight tunnel bioassays confirmed attraction of female Caribbean fruit flies, Anastrepha suspensa (Loew), to volatiles from aqueous solutions of avian fecal material and methanol extracts of avian fecal material. Attraction was highest to freshly prepared and 72-h-old solutions of crude material. In direct comparisons between aqueous solutions of crude material and weight-equivalent amounts of methanol extract, more females were captured in response to volatiles from crude material in tests of 0-, 24- and 72-h-old solutions. Ammonia release rate was greater from the crude material than from the methanol extract in tests of 0-, 24- and 48-h-old solutions, The greatest amount (? sd) of ammonia was released from freshly prepared aqueous solutions of crude material (777 ? 250 .tg/h from 75 mg of crude material) but dropped within 24 h (288 ? 96 jtg/h from 75 mg of crude material) and then stayed close to that level. The greatest amount of ammonia released from methanol extracts was obtained from freshly prepared solutions (229 ? 70 pg/h from 75 mg crude material weight equivalent), also dropped within 24 h (98 ? 12 jg/h from 75 mg crude material weight equivalent) and then stayed fairly constant. Numbers of flies captured by either solution were directly correlated with ammonia release within the first 48 h of testing only, indicating that ammonia was partially or wholly responsible for attraction to the crude material during the first 48 h of testing. An increase in capture of females by volatiles from avian fecal material after 72 h in aqueous solution, which was observed in all tests, indicates that some chemical(s), other than ammonia, remain to be identified that are involved in fruit fly attraction.

SYSTEMS TO MONITOR AND SUPPRESS CERATITIS CAPITATA (DIPTERA: TEPHRITIDAE) POPULATIONS

A synthetic food-based attractant, and a painted cylindrical dry trap that protects the synthetic lures from the environment, were developed to replace liquid protein-baited traps. This trapping system was tested for capture of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). The dry trap is constructed of acetate film with a painted band that provides a visual cue; it contains internally-placed toxicant panels to kill flies that enter the trap. Field trials conducted in Guatemala suggested that a solid-colored material could be substituted for the painted trap body. We also evaluated a sticky insert made from commercially produced adhesive paper as a replacement for the toxicant panels. Unlike paintable sticky adhesives, the sticky material on the adhesive paper insert does not adhere to the skin of personnel who service the traps. An open-bottom trap made of green opaque plastic with a sticky insert captured more C. capitata than the closed-bottom painted trap with a toxicant panel. When used in conjunction with sterile insect release technology, the open-bottom dry trap baited with food-based synthetic attractant often caught wild C. capitata in numbers equal to those caught by trimedlure-baited Jackson traps, but the dry trap caught many fewer sterile C. capitata.

Identification of a male-produced pheromone ofAnticarsia gemmatalis (Hübner) (Lepidoptera; Noctuidae) attractive to conspecific males

Observations in the laboratory and in the field indicated that maleAnticarsia gemmatalis (Hübner), the velvetbean caterpillar (VBC), are attracted to conspecific courting males. Male VBC subsequently were found to be attracted to extracts of male abdominal tips including the extrudable hairpencils. The active chemical in these extracts was identified as (Z,Z,Z)-3,6,9-heneicosatriene, which is also one of the major components of the female VBC sex pheromone. Male VBC in a wind tunnel and in the field exhibited a bimodal response distribution to a range of ratios of the (Z,Z,Z)-3,6,9-heneicosatriene and (Z,Z,Z)-3,6,9-eicosatriene, with one maximum at the pure heneicosatriene alone and the other at the 60∶40 female blend. This demonstrates that the male response to the male hairpencil component is distinct from that to the female sex pheromone.

Comparative laboratory methods for assaying behavioral responses of Rhagoletis pomonella flies to host marking pheromone

In tests on Rhagoletis pomonella flies, we compared previously‐reported laboratory approaches used in assaying behavioral responses of tephritid flies to host marking pheromone with new approaches described here. The foremost criterion used in choosing the most effective assay approach was that of a very high degree of fly discrimination between pheromone‐treated and untreated oviposition sites. Other criteria accentuated a comparatively low amount of time, a low amount of pheromone, a low number of flies, and a low number of oviposition sites (real or artificial fruit) required to conduct an assay. The method that proved to fulfill these criteria to the greatest degree involved: placing 15 treated Crataegus viridis host fruit and 15 untreated C. viridis fruit simultaneously in a test cage with a single continuously‐observed female for up to 60 min, recording whether the female accepted for oviposition or rejected each fruit visited, and removing the female from each accepted fruit just before initiation of ovipositor dragging and deposition of contaminating marking pheromone. In conducting assays associated with chemical purification and identification of pheromonal components, we found this method to be very effective when the 15 treated fruit consisted of 5 sets of 3 fruit, one set treated with crude pheromone (as a standard) and each of the other sets treated with a different chromatographic fraction of pheromone.