Selectivity of novel and traditional insecticides used for management of whiteflies on the parasitoid Encarsia formosa

Abstract

BACKGROUND Encarsia formosa Gahan is the most important parasitoid exploited for the control of whitefly pests of vegetable crops. However, the non‐target effects of recently developed insecticides for controlling whiteflies toward this biocontrol agent is little documented. Here we evaluated the susceptibility of E. formosa adults and juveniles to eight commonly used insecticides against whiteflies. RESULTS Residual toxicity tests on glass showed that E. formosa adults were susceptible (over 98% mortality after 6 h treated) to field concentrations of the tested neonicotinoids (imidacloprid, acetamiprid, nitenpyram and thiamethoxam), abamectin, cyantraniliprole, and sulfoxaflor at their field concentrations. Pyriproxyfen was harmless to both adult and pupae of E. formosa. A risk quotient analysis showed that toxicity of pyriproxyfen to E. formosa adults was the lowest, followed by acetamiprid and cyantraniliprole. In the leaf residues test, mortality of E. formosa adults under all insecticides decreased when the residue age increased. Interestingly, E. formosa experiencing contact with the residues of most insecticides, except pyriproxyfen and abamectin, parasitized significantly more hosts 5‐days after treatment, suggesting a hormetic effect on parasitism. CONCLUSION The risk assessment of insecticides indicated that pyriproxyfen and cyantraniliprole were the least toxic to E. formosa. Our results suggest that the inclusion of the insecticides in sustainable integrated pest management programs of whiteflies should be carefully evaluated on a case‐by‐case basis. © 2019 Society of Chemical Industry

Feeding Behavior and Virus-transmission Ability of Insect Vectors Exposed to Systemic Insecticides

“…Therefore, our results suggested that flonicamid was the only insecticide of those tested that could reduce both the primary and secondary spread of TuYV. Flonicamid has been described as an insecticide that inhibits the feeding behavior of aphids within 0.5 h of treatment without noticeable poisoning symptoms, such as convulsion, and this antifeeding activity remains until the insect dies [64]. This fact is consistent with the long duration of nonprobing in flonicamid-treated plants (WDI: 21,299.8 ± 1582.7 s) compared with untreated plants (WDI: 5905.4 ± 977.8 s).…”

“…In IPM programs, chemical control should be selective towards the target pest species and ideally harmless towards nontarget beneficial organisms [61,62]. Several studies evaluated the toxicity of the insecticides used in the present work on nontarget organisms [63][64][65]. Some of these chemical compounds may have undesirable effects on specific biocontrol agents; therefore, their inclusion in sustainable IPM programs should be adopted with caution.…”

Detrimental sublethal effects hamper the effective use of natural and chemical pesticides in combination with a key natural enemy of Bemisia tabaci on tomato

“…Insecticides have been widely used in tomato and other crops due to their effective pest control and rapid action against susceptible populations of B. tabaci 54 . However, environmentally safe approaches (e.g., combining natural enemies and selective products) should be prioritized to avoid a build‐up of insecticide resistance 11,55,56 . In our study, the B. tabaci population was able to increase when exposed to dry residues of BCO on tomato leaves.…”

Enemigos naturales nativos de mosca blanca (Hemiptera: Aleyrodidae) en el cultivo de ejote francés en Chimaltenango, Guatemala

“…Tecnología y Salud, 6(2) 2019, 149-157 Ciencia, Tecnología y Salud, 6(2), 2019, 98 tiametoxan, las cuales son empleadas en la producción de hortalizas de la región. Otras moléculas empleadas en la región que también han sido reportadas como dañinas para E. formosa son: abamectina, cyantraniliprole y sulfoxaflor (Wang et al, 2019). El empleo de estos podría estar afectando las poblaciones nativas de E. formosa reduciendo considerablemente sus poblaciones.…”