Effects of bio‐pesticides on Eretmocerus warrae (Hym., Aphelinidae), a parasitoid of Bemisia tabaci (Hom., Aleyrodidae)

Abstract

The sweet potato whitefly Bemisia tabaci (WF) can be controlled by two commercial neem products, NeemAzal‐T/S® (1% azadirachtin) for foliar application, and NeemAzal‐U (17% azadirachtin) for soil application, alongwith two biorational products of microbial origin, Abamectin (avermectin) and Success® (spinosad). Side effects of these products were tested in a laboratory bioassay against a native aphelinid, Eretmocerus warrae (EW). Eggs and early larval instars of the parasitoid, commonly found outside the host body, were highly susceptible to foliar spray of neem with only 8%, 18% and 55% emergences of adults from treated eggs. larval and pupal stages respectively at recommended dose‐rates of 5 ml/l and 1%, 8% and 40% at twice recommend dose‐rate (10 ml/l). Soil application with NeemAzal‐U marginally affected EW. At highest tested dose‐rate of 3.0 g/l, 46%, 64% and 81% emergence was recorded after treatement of plants harbouring WF parasitized by egg, larval and pupal stages of EW respectively. In contrast to neem application, Success® and Abamectin caused high mortality in development stages of the parasitoids. In particular, abamectin was highly toxic to the parasitoids with less than 1% emergence from either of the three development stages if treated with 1–2 ml/l.

Lethal and sub-lethal effects of insecticides on natural enemies of citrus scale pests

“…Spinosad was initially described as an environmentally and toxicologically reduced-risk compound (Copping and Menn 2000). However, several studies proved its toxicity to many Hymenopteran parasitoids in various formulations (Michaud 2003; Williams Table 2 The side-effects of pesticides on adult parasitoids, % mortality, reduction in parasitism compared to the control (RP %) and sex ratio of the progeny produced by the surviving females under laboratory conditions Haseeb et al 2004;Williams and Price 2004;Wang et al 2005;Kumar et al 2008) in agreement with our findings. The trials conducted on C. lycimnia represent the first contribution in the evaluation of pesticide toxicity on parasitoids belonging to this genus, which includes important natural biocontrol agents of several scale pests on citrus and other crops all over the world (Abd-Rabou 2001;Bernal et al 2001).…”

Effects of neem on adults of Eretmocerus warrae (Hym., Aphelinidae), a parasitoid of Bemisia tabaci (Horn., Aleyrodidae) in tropical horticulture systems

“…tributed systemically (Gonzalez-Zamora et al 2004;Kumar et al 2008). Moreover, due to a rather short systemic translocation period (two-three days) before emergence, only a small portion of the applied neem was able to accumulate in the plant tissue around the WF feeding sites (Basedow et al 2002;Kumar et al 2005;Thoeming & Poehling 2006;Kumar & Poehling 2006).…”

“…NeemAzal-U and NeemAzal ® -T/S solutions were prepared, based on recommended dose rates and according to our previous studies (Kumar et al 2005;Kumar et al 2008). NeemAzal-U was designed for soil drenching, whereas NeemAzal ® -TS is registered for spray applications.…”

“…In previously reported study we addressed the effects of neem and two microbial based bio-rational pesticides, namely spinosad and abamectin on different life stages of the E. warrae (Kumar et al 2008). However, details on the effects on adult EW are missing.…”

Compatibilidad de Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) y Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae), importantes enemigos naturales de la mosca blanca Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) en cultivos hortícolas, con nuevas barreras físicas selectivas y modernos plaguicidas

“…Como era de esperar, este producto mató al 100% de los adultos de E. mundus y al 97,24% de las pupas tratadas y, además, los pocos insectos que fueron capaces de abandonar el pupario murieron a los 3 días de la emergencia. Nuestros hallazgos coinciden con los resultados obtenidos por Kumar et al (2008) y Sugiyama et al (2011), quienes observaron que el tratamiento de pupas y larvas de E. warrae con spinosad, reducía la emergencia y la longevidad de los adultos, y que la exposición a residuos frescos de dicho insecticida, producía una rápida mortalidad de los adultos y pupas de E. mundus.…”