engleski

Control of european corn borer (Ostrinia nubilalis Hübner) in seedcorn production

European corn borer Ostrinia nubilalis Hübner, (ECB) is a perennial insect pest of corn in Croatia, with infestation levels reaching 50% in many fields the past 10 years. This insect is especially important in seedcorn production because of this crop’ s higher market value. The objective of this study was to determine the efficacy of chemical and biological controls against ECB in seed production fields. Eight treatments were applied to two corn inbreds (Bc 492, Bc 592) at two location (Kopanica, Berava) in Croatia in 1994 and 1995. Treatments were 3 systemic organophosphates (Lebaycid, Rogor, and Ekatin 25 EC), 2 pyrethroids (Sherpa and Karate), two formulations of Bacillus thuringiensis Berlinier (Biobit XL ; WP and FC), and 1 untreated control. Insecticide treatments were applied when at least 2/3 of the plants contained egg masses and at least 1/3 of the plants showed symptoms of injury (shot-holing) in the whorl. Efficacy of the insecticide treatments was evaluated just before harvest by dissecting 50 plants/treatment and counting the number of tunnels, number of live larvae, measuring tunnel length, and grain yield. In 1994, 87% of the plants in the untreated control plots were infested with ECB. The organophosphate treatments reduced the infestation level by 42%, the pyrethroids by 40%, and the Bt treatments by 42%, compared to untreated control. In 1995, 70% of the plants in the untreated control plots were infested with ECB. The organophosphate treatments reduced the infestation level by 32%, the pyrethroids by 30%, and the Bt treatments by 29%, compared to untreated control. In both years, the organophosphate treatments provided the greatest yield protection from ECB. Yields in these treatments were 13-19 % greater than the untreated control. Results from this study show that yields of seedcorn could be significantly increased if ECB population were managed in Croatia.

european corn borer ; Ostrinia nubilalis ; seedcorn production

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