Seletividade de agrotóxicos utilizados na cultura do pessegueiro ao predador Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae)

Abstract

In peach crops, the chemical control is the most used method in pest management, however, in sustainable production systems such as the Integrated Peach Production (IPP), alternative methods based on Integrated Pest Management (IPM) are commended. The natural enemies preservation is one of the most important practices on IPM, so, the use of pesticides that are selective to these organisms should be encouraged, in order to enable the chemical and biological control association. Therefore, this work aimed to evaluate the side effects of sixteen pesticides used in conventional and integrated peach production on larvae and adults of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae), under laboratory bioassays (25±1oC temperature, 70±10% relative humidity, and 14h photophase), using the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC) standard methodology. The larval and adults bioassays consisted on the exposure of the insects to a fresh dry pesticide film applied on glass plates. In the larval bioassays, the duration time of each development stage, the mortality, the fecundity and fertility of survival adults were evaluated. In the adults bioassays, it was evaluated the cumulative mortality at 24, 72 and 120 hours after the residual exposure of the insects. The pesticides were classified according to the total toxic effect for the larval stage, and according to the mortality rate for adults, in harmless (<30%), slightly harmful (30-79%), moderately harmful (80-99%) and harmful (>99%), in conformity to IOBC recommendation. For the pesticides [commercial product (active ingredient - % of active ingredient in spray water) evaluated, it follows that: the fungicides Amistar 500 WG (azoxystrobine 0.016), Cuprozeb (mancozeb and cooper oxichloride 0.140 and 0.096), Dodex 450 SC (dodina 0.126), Folpan Agricur 500 WP (folpete 0.200), Manzate 800 (mancozeb 0.256) and Orthocide 500 (captan 0.192); the insecticides Assist (mineral oil 1 2.420) and Oppa (mineral oil 2 1.920); the insecticide/acaricide Vertimec 18 CE (abamectin 0.002) and the herbicide Roundup (gliphosate 1.440) are harmless to larvae and adults of C. externa. The fungicide Folicur 200 EC (tebuconazole 0.320) is slightly harmful for larvae and harmless for adults of C. externa. The insecticide Decis 25 EC (deltametrin 0.002) is moderately harmful and slightly harmful to larvae and adults of the predator, respectively. The herbicide Gramoxone (paraquat dichloride 0.300) is harmful to larvae and harmless to adults, and the insecticide Agritoato 400 (dimetoate 0.160), Imidam 500 WP (fosmet 0.160) e Malathion 500 EC (malathiona 0.240) are harmful to larvae and adults of C. externa. The fecundity and fertility of emerged adults when larvae were exposed to the chemical residuals are not significatively affected by anyone of them. Female adults are less susceptible to chemicals when compared to male adults.