Efeito da época de semeadura de milho sobre os danos causados pelas larvas de Diloboderus abderus (Sturm) (Colcoptera: Melolonthidae) em plantio direto

Abstract

Effect of Planting Dates ofCorn on the Damage Causcd hy Dilobodertis abderus (Sturrn) (Colcoptera: Melolonthidac) Larvae in No-Tillage ABSTRACT -A field experiment was carried out in Cruz Alta. RS. during the 1990/1991 growing seasori, in a Oxissol (Dark-red Latosol). under no-tiliage system, to evaluate thc cffect of planting date of corn on the clamage caused by larvae oU Diloboderus abderus Sturrn, and on thc crop population density and productivity. The experimental dcsign was of complete randomized blocks with split plots and 10 replications. The trcamcnts were the two planting dates (D1 = August 20 and D, = October 1), and the subtreatments the untreated check (NTC) and insecticijie thiodicarh (Semevin 350 RM 700 g a.i./lOO kg ofseeds (SCI). A significantly smaller number of larvae and a higher plant population and yield productivity were ohserved in SCI compared to NTC in D1 . In D, parameters ineasured were cquivalcnt hoth in NTC and SCI. The manipula: tion of the planting date. starting in October, leads to a significant reduction in the attack of larvae.