Persistence of Mating Suppression of the Indian Meal Moth Plodia Interpunctella in the Presence and Absence of Commercial Mating Disruption Dispensers.

Leanage K W Wijayaratne,Charles S Burks

doi:10.3390/insects11100701

Abstract

Simple SummaryA novel assay system was used to facilitate replicated studies examining the impact of commercial mating disruption dispensers on Plodia interpunctella. Both direct and indirect exposure to passive mating disruption dispensers for as little as 2 h suppressed mating throughout the rest of a 10 h scotophase. This is the first direct evidence that for P. interpunctella, transient exposure to commercial mating disruption dispensers is sufficient to suppress male orientation to females without re-exposure to the mating disruption dispensers. An improved understanding of mechanisms for mating disruption can improve both development of future products and how current products are used.The Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is controlled by commercial mating disruption dispensers using passive release to emit high concentrations (relative to females or monitoring lures) of their principal sex pheromone component, (9Z,12E)-tetradecadienyl acetate. Since P. interpunctella is sexually active throughout the scotophase, an assay system was developed to determine the importance of direct interaction of the male with the dispenser, and whether exposure to mating disruption early in the night is sufficient to suppress mating throughout the night. Exposure to mating disruption dispensers in the mating assay chamber for the first two hours of a 10-h scotophase significantly reduced mating when females were introduced four hours later. Mating was also reduced to a lesser degree in a concentration-dependent manner based solely on re-emission of pheromone, and when males were exposed outside the mating assay chamber. These results indicate that the commercial mating disruption dispensers can suppress mating throughout the night based on interaction with the dispenser early in the night. Desensitization resulting from attraction to a high-concentration pheromone source is important to this suppression, but other factors such as re-emission from the environment may also have a role. These observations imply a non-competitive mechanism for P. interpunctella with the product studied, and suggest that effectiveness of the mating disruption dispenser might be augmented by using them in conjunction with another formulation such as an aerosol or micro-encapsulated product.

Highlights

Semiochemical control methods have become an increasingly important part of insect pest management over recent decades [1,2]
Adults were from a laboratory colony of P. interpunctella established from moths emerged from a load of infested pistachios received from Kern County in 2015, and maintained in the laboratory for 50 to 60 generations at the time of the experiments
When P. interpunctella was paired in 28 mL or 946 mL arenas, mating was almost immediate, 66–100% of the pairs mated (Table S1), and there was no significant difference in the proportion of pairs

Summary

Introduction

Semiochemical control methods have become an increasingly important part of insect pest management over recent decades [1,2]. Mating disruption is one of several pest management strategies that use pheromones or other semiochemicals for control of insect pests [3]. Insects 2020, 11, 701 mass trapping [4], attract-and-kill [5], and push-pull strategies [6]. Mating disruption mechanisms are categorized most broadly as either competitive or non-competitive [2,7]. Both competitive and non-competitive mating disruption may be accomplished by one or a combination of mechanisms;. E.g., competitive attraction or induced arrestment for competitive disruption; or desensitization, camouflage, or sensory imbalance for non-competitive disruption [7]. Different formulations are used, such as aerosol, hand-applied dispensers, or micro-encapsulated flowable products [2,7]

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Conclusion