Pest Management Science (2020) 76, 2918-2924

Joseph Onwusemu Disi, Steven Van Timmeren, Brian Gress, Frank Zalom, Rufus Isaacs and Ashfaq Sial (2020)
Insecticide residue longevity for on-site screening of Drosophila suzukii (Matsumura) resistance
Pest Management Science 76 (9), 2918-2924
Abstract:
BACKGROUND
Preventative application of insecticides reduces marketable yield losses caused by Drosophila suzukii females that selectively lay eggs into ripe and ripening fruits. However, repeated applications of insecticides increase the risk of resistance development. It is therefore critical to test field-collected flies on-site to assess the level of sensitivity of D. suzukii to insecticides to monitor resistance, before it becomes a widespread issue. This requires that insecticide-treated vials be readily available to conduct bioassays. Thus, bioassays were conducted using malathion-, methomyl-, zeta-cypermethrin-, phosmet-, spinetoram- and spinosad-treated scintillation vials at 1 to 28 days after treatment to assess how residue age affects insecticide toxicity in scintillation vials. The impact of temperature on residue longevity was also assessed.
RESULTS
Insecticide-treated vials stored for 28 days provided reliable estimates of susceptibility of D. suzukii to some of the tested insecticides. The toxicity of malathion remained consistently high throughout the experiment followed by methomyl. However, toxicities of zeta-cypermethrin, phosmet were variable whereas those of the spinosyns declined relatively quickly. Overall, storage temperature did not affect the residual toxicity of most of the tested insecticides except zeta-cypermethrin.
CONCLUSION
These findings suggest that the toxicity of insecticide residues in treated vials remains active for < 28 d for malathion and < 21 and 28 days in methomyl-treated vials stored at 4 °C in Georgia and Michigan, respectively. However, the toxicities of spinosad, zeta-cypermethrin and phosmet were less consistent. Hence, vials treated with these insecticides should be freshly made to be effective for screening D. suzukii field populations for resistance.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Frank G. Zalom, Rufus Isaacs, Ashfaq A. Sial

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Drosophila suzukii