Attraction of Choristoneura Rosaceana (Lepidoptera: Tortricidae) to Pheromone Blends in Ratios Produced in Females’ Pheromone Gland or Emitted by the Females in Michigan Apple Orchards

Trap captures of obliquebanded leafroller, Choristoneura rosaceana (Harris) to pheromone blends in ratios approximating those reported in pheromone glands and a novel blend based on a volatile headspace collection from live virgin females were evaluated in field experiments in Michigan apple orchards. In an initial field trapping study, pheromone lures composed of either a three- or four-component blend approximation of the blend present in female pheromone glands at doses ranging from 0.1 to 20 mg/lure were compared. The four-component blend was a combination of (Z)-11-tetradecenyl acetate (Z11-14:Ac), (E)-11-tetradecenyl acetate (E11-14:Ac), (Z)-11-tetradecen-1-ol (Z11-14:OH), and (Z)-11-tetradecenal (Z11-14:Al) in a ratio of 96.5:1.8:1.4:0.2, respectively, while the three-component blend lacked Z11-14:Al. Pheromone emissions by groups of virgin females and commercial lures were collected in the laboratory and analyzed by gas chromatography. These data were used to formulate a new pheromone lure that was compared to a commercial lure in a second trapping study. In the first field study, traps baited with 10 mg pheromones or above captured significantly more moths than traps baited with 1 mg or less, regardless of the blend. Surprisingly, groups of virgin females only emitted two detectable pheromone components, Z11-14:Ac and Z11-14:OH in a ratio of 37:63 which was substantially different from the blends detected in pheromone glands in the literature. The newly formulated pheromone lure based on females’ emission was more than twice as attractive as the commercial lure which emitted a 74:5:21 three-component blend of Z11-14:Ac, E11-14:Ac, and Z11-14:OH, indicating that the response of C. rosaceana to its pheromone was more strongly mediated by the pheromone quantity relative to the blend ratio.

13-Tetradecenyl acetate, a female-produced sex pheromone component of the economically important click beetle Melanotus communis (Gyllenhal) (Coleoptera: Elateridae)

Species-specific behavior-modifying chemicals have been used for more than 50 years for monitoring and management of insect pests of agriculture and human health. Elaterid beetle larvae are among insect pests in soil that are increasingly problematic, in part due to the lack of effective management strategies. However, little is known about the insect-produced chemicals that mediate the reproductive behavior of these pests. We used chemical and behavioral studies to identify, synthesize, and field test the sex attractant pheromone of adults of Melanotus communis, commonly called the corn wireworm, the larvae of which are economically important pests of U.S. crops. Our results indicated that a single female-produced chemical, 13-tetradecenyl acetate, was strongly attractive to conspecific male beetles, and did not appear to attract other species. In field evaluations, male M. communis exhibited a dose-dependent response to this compound. In a trial comparing different slow-release dispensers, a small rubber septum impregnated with the chemical was as effective as and easier to use than a plastic bag dispenser. Given that the sex attractant of this insect consists of a single compound that can be readily synthesized, its development for monitoring and management of the corn wireworm may be economically feasible.

Minor components modulate sensitivity to the pheromone antagonist Z11-14:Ac in male lightbrown apple moth, Epiphyas postvittana (Lepidoptera: Tortricidae) in the field

Epiphyas postvittana is a major horticultural pest in many countries, including New Zealand. Recently, two minor components (E)-11-tetradecen-1-ol and (E)-11-hexadecenyl acetate were found to increase the attraction of a previously identified two-component sex pheromone (95:5 blend of (E)-11-tetradecenyl acetate [E11-14:Ac] and (E,E)-9,11-tetradecadienyl acetate [E9,E11-14:Ac]) of Epiphyas postvittana. We hypothesised that the interaction between these minor components and the behavioural antagonist (Z)-11-tetradecenyl acetate (Z11-14:Ac) would modulate its antagonistic effect. The effect of increasing the ratio (0.5—10%) of Z11-14:Ac was tested in traps baited with E11-14:Ac and E9,E11-14:Ac (95:5), with or without the addition of the two minor compounds. Catch decreased as the percentage of Z11-14:Ac increased (χ2=108.74; d.f.=9; P<0.001). Overall, more moths were caught in traps baited with four- vs two-component lures (χ2=9.81; d.f.=1; P=0.002); in pair-level comparisons, significant differences in catch number between the two- and four-component lures were observed when the E11-14:Ac : Z11-14:Ac ratio was 99:1 (P=0.031) or 98:2 (P=0.047). The addition of the two minor components mitigated the reduced catch effect due to lower proportions of E11-14:Ac and the presence of 1—2% antagonist.

Design, Synthesis, and Biological Evaluation of the Sex Pheromone of the Asian Corn Borer, Ostrinia furnacalis (Guenée)

A convenient total synthesis of (Z)-12-tetradecenyl acetate (1a) and (E)-12-tetradecenyl acetate (1b), which are the sex pheromones of Ostrinia furnacalis (Guenée), has been achieved. The target mixture molecules, of a cis-to-trans-isomer ratio of 27 to 73, were synthesized in 40% overall yield and through [13C + 1C] synthetic strategy in five steps from commercially available and cheap industrial brassylic acid as key starting material. The electroantennogram (EAG) responses of synthetic sex pheromone to ACB male moths were conducted. The results showed that the target mixture molecules were found to have a good activity and displayed significantly stronger EAG responses ranging from 10 to 1000 μg, and the optimized stimulating dosage of the activity of synthetic sex pheromone to ACB males is 10 μg. Compared with the existing routes, this synthetic approach is operationally simple, good-yielding, and cost-effective, which could serve as a basis for developing the techniques of sex pheromone mass trapping or mating disruption and providing an environmentally benign method to control ACB pests.

Identification of the Sex Pheromone of Isoceras sibirica Alpheraky (Lepidoptera, Cossidae)

We discovered that extracts of the female sex pheromone gland of the carpenterworm moth Isoceras sibirica Alpheraky, a pest of Asparagus offi cinalis Linn., contained (Z)-7- tetra decen-1-ol (Z7 - 14:OH), (Z)-9-tetradecen-1-ol (Z9 - 14:OH), (Z)-7-tetradecenyl acetate (Z7 - 14:Ac), (Z)-9-tetradecenyl acetate (Z9 - 14:Ac), and (Z)-9-hexadecadecenyl acetate (Z9 - 16:Ac). The average levels of the chemicals in a single sex pheromone gland of a calling moth were (0.71 ± 0.24) ng, (1.42 ± 0.44) ng, (4.36 ± 0.32) ng, (8.71 ± 0.26) ng, and (0.82 ± 0.38) ng, respectively. The electroantennography (EAG) analysis of these chemicals and their analogues demonstrated that Z9 - 14:Ac triggered signifi cantly the male EAG response. Traps with rubber septa lure impregnated with Z9 - 14:Ac (500 μg/septum), Z7 - 14:Ac (250 μg/septum), and Z9 - 16:Ac (50 μg/septum) were more effective in catching male moths than traps with other baits or virgin females. Addition of Z7 - 14:OH and Z9 - 14:OH to rubber septa did not enhance the effi ciency of the trap.

Trap response of cutworm moths (Abagrotis orbis) to a sex-attractant lure in grape vineyards

Larvae of Abagrotis orbis (Grote) (Lepidoptera: Noctuidae) are climbing cutworms and can damage grapevines, Vitis vinifera L. (Vitaceae), in early spring by consuming expanding buds. A sex attractant would be useful for monitoring this insect in commercial vineyards. (Z)-7-Tetradecenyl acetate and (Z)-11-hexadecenyl acetate were found in extracts of female abdominal tips. In multiple field experiments, male A. orbis were captured in traps baited with a combination of these two chemicals but not in traps baited with either chemical alone. Males were trapped from mid-September to early October in south-central Washington and south-central British Columbia. Other noctuid moths (Mamestra configurata Walker, Xestia c-nigrum (L.), and Feltia jaculifera (Guenée)) were also captured in traps baited with the A. orbis pheromone and may complicate the use of this lure to monitor A. orbis. Abagrotis discoidalis (Grote) was captured in traps baited with (Z)-7-tetradecenyl acetate but not in traps baited with the two chemicals together.