Spring behaviour of the European corn borer, Ostrinia nubilalis (Lepidoptera, Pyralidae) larvae in south-western Slovakia
1998
Cagan, L. (Slovak Agriculture Univ., Nitra (Slovak Republic). Dept. of Plant Protection)
Spring behaviour of European corn borer (ECB) larvae was observed in south-western Slovakia during 1989-1996. The number of larvae in maize stems covered with soil and in intact maize stems was compared. The first larvae of the ECB were found on the soil surface from 16 March to 23 April (depending on the year). The highest spring movement of the ECB larvae was found in the second half of April. Soil temperature was the main factor influencing the movement of the larvae, which were active even at temperatures below 10 degrees C. High rainfall in the first half of April 1990 and in the second half of March 1992 forced some larvae to the soil surface. The time between spring movement of the larvae and their pupation was nearly two months. The time of pupation did not correlate with the time of spring movement of larvae. Analysis of the remnants of maize stems covered with soil showed that all larvae abandoned their winter shelters during spring. The number of larvae in new shelters (made from corrugated paper) was almost half the number of larvae surviving in intact maize stems on the surface of the soil
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