|Siderhurst, Matthew - Eastern Mennonite University|
|Derstine, Nathan - Eastern Mennonite University|
Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2015
Publication Date: 6/15/2015
Citation: Siderhurst, M.S., Jang, E.B., Carvalho, L.A., Nagata, J.T., Derstine, N.T. 2015. Disruption of Darna pallivitta (Lepidoptera: Limacodidae)by conventional and mobile pheromone deployment. Journal of Insect Science. 15(1):67. DOI: 10.1093/JISESA/IEV052.
Interpretive Summary: Infestations of the nettle caterpillar were first discovered at a nursery in Panaewa, on the eastern side of the island of Hawai’i. Darna pallivitta caterpillars have a wide host range, feeding on many agricultural crops, including coffee and macadamia, as well as landscape plants thereby threatening a nursery industry valued at $97.7 million. Transportation of contaminated nursery stock is a potential source of outbreaks in unaffected areas of Hawai'i, other Hawai’ian islands and the U.S. mainland. D. pallivitta is a problem for farmers as a direct pest and secondarily as a quarantine pest, causing additional losses when shipments of infested plants are rejected by quarantine inspectors. Already inspectors have intercepted caterpillars and cocoons in California. Additionally, the caterpillar constitutes a human health hazard due to the painful sting, which results from contact with its urticating hairs (for which it is named). Monitoring of moth populations has been aided by the identification of a sex pheromone lure, n-butyl (E)-7,9-decadienoate. The pheromone lure has been used in trapping grids on several islands to monitor and delimit moth populations and to help document declines in D. pallivitta associated with releases of a parasite that attacks the caterpillars. While moth sex pheromone lures can be used as monitoring tools, they also have potential to directly reduce pest moth populations when used in pheromone-based control strategies, such as mating disruption. This research evaluated the use of pheromone mating disruption techniques to control D. pallivitta using both conventional disruptors and new techniques called mobile mating disruption (pheromone carried and released by melon flies).
Technical Abstract: Nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae), is an invasive pest with established populations on three Hawai’ian islands. Indigenous to Southeast Asia, D. pallivitta caterpillars defoliate ornamentals and pose a human health hazard due to urticating hairs that can cause painful skin reactions. Identification of the pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOn-Bu) from D. pallivitta has made it possible to investigate pheromone disruption for control applications. Conventional pheromone mating disruption trials showed marked decreases in the mean number of male D. pallivitta captured in E7,9-10:COOnBu-treated fields compared to control fields. For traps baited with E7,9-10:COOnBu, percent disruptions were 94.4% and 92.1% for septa (1 g pheromone/ha, one week trial duration) and spirals (6 g pheromone/ha, eight weeks duration) respectively. For traps baited with virgin female D. pallivitta, percent disruption was 73.3% using septa disruptors (1 g pheromone/ha, one week trial duration). Mobile mating disruption (MMD) using melon fly, Bactrocera cucurbitae, (Diptera: Tephritidae) as carriers for E7,9-10:COOn-Bu was evaluated in the following three areas: fly survivorship, attraction of male moths to treated flies, and moth disruption in a small-scale field trial. Application of E7,9-10:COOnBu showed no significant decrease in survivorship at 50 and 80 µg/fly, however, decreased survivorship was observed at 100 µg/fly and linear regression showed E7,9-10:COOnBu dose was significantly correlated with B. cucurbitae survivorship. Traps containing honey-pheromone fed flies attracted and caught D. pallivitta over a one week period demonstrating the attractiveness of the carrier. Releasing E7,9-10:COOnBu-fed, sterile, B. cucurbitae (~2 g pheromone/ha, one week duration) resulted in significantly reduced trap catches in treatment fields compared to control fields on the first two days of the field trial. Percent disruptions were 83.9% on day 1 and 64.9% on day 2. These results suggest that both conventional pheromone mating disruption and MMD have potential to be used to control D. pallivitta.