Immatures of Chironomidae (Insecta – Diptera) under the action of pesticides in irrigated rice field

We collected 589 larvae distributed among a control treatment and seven pesticide treatments (Only®, Imazethapyr, Imazapic, Clomazone, Quinclorac, Carbofuran and Fipronil). The most abundant genera were Kiefferulus spp., Chironomus spp. and Dicrotendipes spp. ANOVA showed a significant difference (p < 0.05) in the density of Chironomidae larvae in the first sample between the Fipronil and Control treatments. ANOSIM also showed variation in the Chironomidae community composition and trophic groups. The PRC analysis showed that the pesticide concentration was higher on the first 10 days after its application. The pesticides used in the rice crop had an initial negative effect to the Chironomidae community, dissipating during the development of the crop.