Effects of Plant Species, Insecticide, and Exposure Time On the Efficacy Of Barrier Treatments Against Aedes albopictus

Abstract

The effect of 5 plant species (arborvitae [Thuja occidentalis], boxwood [Buxus sp., Japanese honeysuckle [Lonicera japonica], rhododendron [Rhododendron sp.], and zebra grass [Miscanthus sinensis]) and 2 rates of lambda-cyhalothrin (3.13 ml and 6.25 ml active ingredient [AI]/liter) on knockdown (1 h) and mortality (24 h) of adult female Aedes albopictus was evaluated over an 8-wk period. A significant difference in knockdown was observed between the 2 rates of lambda-cyhalothrin on the 5 plant species, with the highest proportion of knockdown observed on zebra grass and rhododendron treated at the higher rate. Although mortality was 60% and 85% on the 5 plant species at the low and high rates of lambda-cyhalothrin, respectively, a significant difference between the 2 rates was only observed on boxwood and Japanese honeysuckle (P , 0.0001). We also tested the residual toxicity of 3 barrier sprays (lambda-cyhalothrin, bifenthrin, and deltamethrin) and evaluated the efficacy of a short (5-min) exposure to the insecticides on knockdown and mortality of adults over time. Significantly higher knockdown was observed with lambda-cyhalothrin compared with bifenthrin and deltamethrin (P , 0.0001). Mean knockdown was~98%, 92%, and 20% for lambda-cyhalothrin, bifenthrin, and deltamethrin, respectively, at week 2, and~98%, 0%, and 44%, respectively, 8 wk after treatments were applied. Adult mortality from the 3 chemical treatments, however, remained above 90% throughout the study. Lastly, the trends in mean proportion of knockdown were similar for mosquitoes exposed for either 5 min or 24 h to the 3 chemicals. An overall decline in mean mortality over time, however, was observed for mosquitoes exposed for 5 min to the chemicals compared with mortality from the 24-h exposure. The results suggest that lambda-cyhalothrin can be an effective barrier spray treatment against Ae. albopictus adults because its efficacy is limited little by plant species, it has long residual toxicity, and it is effective following only 5 min of exposure.

Bioassays and Methodologies for Insecticide Tests with Larvae of Trogoderma granarium (Everts), the Khapra Beetle

“…It is different from the Suspend ® and Centynal ® formulations of deltamethrin that do not have this technology, but the amount of active ingredient and label specifications for application as a residual surface treatment are the same for all three formulations. Deltamethrin Polyzone ® has been tested in a number of recent studies as a simulated barrier treatment for mosquitoes in outdoor situations and has been proven effective with increased residual persistence compared to standard commercial formulations of deltamethrin [14,15,16]. In our test with a stored product insect, which is the first test reported in the US with this formulation of deltamethrin, residual persistence was far less in our arenas held outdoors compared to those held in the shed or inside the lab.…”

A Review of Studies Evaluating Insecticide Barrier Treatments for Mosquito Control From 1944 to 2018

“…Li et al 33 Muzari et al 34 McMillan et al 19 Qualls and xue 21 Trout et al 30 Trout 32 Bibbs et al 29 Britch et al 24 Cilek 23 Doyle et al 31 Fulcher et al 28 McMillan et al 19 Qualls et al 3 Qualls et al 26 Trout et al 30 Tempo SC Ultra 11.8% Beta-Cyfluthrin…”

“…28 Demand CS (9.7% lambda-cyhalothrin), Talstar P (7.9% bifenthrin), and Suspend Polyzone (deltamethrin 4.75%) were evaluated against Ae albopictus in laboratory bioassays. 19 Insecticide was applied using a STIHL SR 200 backpack sprayer. Two exposure times were evaluated to determine the validity of the standard 60 minutes and 24 hour exposure times.…”