Mating disruption of Guatemalan potato moth Tecia solanivora by attractive and non-attractive pheromone blends

The protein and volatile components of trail mucus in the Common Garden Snail, Cornu aspersum

The Common or Brown Garden Snail, Cornu aspersum, is an invasive land snail that has successfully colonized a diverse range of global environments. Like other invasive land snails, it is a significant pest of a variety of agricultural crops, including citrus, grapes and canola. Cornu aspersum secretes a mucus trail when mobile that facilitates locomotion. The involvement of the trail in conspecific chemical communication has also been postulated. Our study found that anterior tentacle contact with conspecific mucus elicited a significant increase in heart rate from 46.9 to 51 beats per minute. In order to gain a better understanding of the constituents of the trail mucus and the role it may play in snail communication, the protein and volatile components of mucus trails were investigated. Using two different protein extraction methods, mass spectrometry analysis yielded 175 different proteins, 29 of which had no significant similarity to any entries in the non-redundant protein sequence database. Of the mucus proteins, 22 contain features consistent with secreted proteins, including a perlucin-like protein. The eight most abundant volatiles detected using gas chromatography were recorded (including propanoic acid and limonene) and their potential role as putative pheromones are discussed. In summary, this study has provided an avenue for further research pertaining to the role of trail mucus in snail communication and provides a useful repository for land snail trail mucus components. This may be utilized for further research regarding snail attraction and dispersal, which may be applied in the fields of agriculture, ecology and human health.

Optimizing Efficiency of Aerosol Mating Disruption for Navel Orangeworm (Lepidoptera: Pyralidae)

Improved cost efficiency for aerosol mating disruption for the navel orangeworm, Amyelois transitella Walker, was examined in experiments performed between 2015 and 2017. A programmable dispenser was used to explore the effects of frequency of treatment, time of night when pheromone was emitted, and the concentration of pheromone required. A negative curvilinear trend of males captured as a function of emission frequency was evident in the range of 2-12 emissions per hour. A subsequent experiment found greater trap suppression when the same amount of active ingredient was emitted seven times per hour compared with the same amount of material emitted at twice the concentration but half the frequency. Another experiment found no significant difference in cumulative trap suppression between treatment for the last 4 or 6 h of the night compared with 12 h. A subsequent experiment comparing a current commercial mating disruption system emitting for 12 h with a proposed alternative emitting more material per hour for fewer hours showed similar levels of suppression of males in pheromone traps. A season-long efficacy trial using dispensers deployed and programmed based on these findings demonstrated significant reduction of damage to Nonpareil almonds treated with mating disruption. These data reveal important information about the response of the navel orangeworm to aerosol mating disruption, which provides improved cost-effectiveness compared with the status quo ante. These findings for navel orangeworm are discussed in relation to studies of aerosol mating disruption for the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae).

Non-Host Plant Volatiles Disrupt Sex Pheromone Communication in a Specialist Herbivore

The ecological effects of plant volatiles on herbivores are manifold. Little is known, however, about the impacts of non-host plant volatiles on intersexual pheromonal communication in specialist herbivores. We tested the effects of several prominent constitutive terpenoids released by conifers and Eucalyptus trees on electrophysiological and behavioral responses of an oligophagous species, Plutella xylostella, which feeds on Brassicaceae. The non-host plant volatile terpenoids adversely affected the calling behavior (pheromone emission) of adult females, and the orientation responses of adult males to sex pheromone were also significantly inhibited by these terpenoids in a wind tunnel and in the field. We suggest that disruption of both pheromone emission and orientation to sex pheromone may explain, at least in part, an observed reduction in herbivore attack in polyculture compared with monoculture plantings. We also propose that mating disruption of both male and female moths with non-host plant volatiles may be a promising alternative pest management strategy.

Mating disruption of Coleophora deauratella (Lepidoptera: Coleophoridae) using laminate flakes in red clover seed production fields

BACKGROUND

The red clover casebearer, Coleophora deauratella, is a significant pest in red clover (Trifolium pratense) seed production regions throughout the world. The internal feeding nature of C. deauratella larvae makes infestations difficult to control with insecticide. We test the ability of Hercon Disrupt Micro-Flakes(®) releasing the complete pheromone blend of C. deauratella to disrupt communication and mating in red clover seed production fields.

RESULTS

Initial small-plot (0.25 ha) trials found a significant reduction (93.6 ± 2.9%) of male C. deauratella captured in pheromone-treated plots compared with untreated controls. Subsequent large-plot (5 ha) mating disruption trials found a significant reduction (72.3 ± 5.7%) in male C. deauratella captured in pheromone-treated plots compared with untreated control plots over the growing season. Furthermore, larval numbers were significantly reduced and seed yield was increased in pheromone-treated plots compared with untreated control plots. In a concurrent small-plot (0.0625 ha) trial with various flake densities, disruption increased with pheromone flake density, and the resulting graphical disruption profiles matched the theoretical predictions of mating disruption by competitive attraction.

CONCLUSION

Pheromone-mediated mating disruption with laminate flakes has the potential to suppress C. deauratella populations and may help to reduce damage even at high pest densities. © 2014 Society of Chemical Industry.