Effectiveness of Trichogramma evanescens West., (Hymenoptera, Trichogrammatidae) in parasitizing the eggs of the European corn borer on different host plants [Ostrinia nubilalis]
1984
Manojlovic, B. (Institut za zastitu bilja, Beograd (Yugoslavia))
It was investigated the egg parasitism of the European corn borer layed in wild life on corn, hemp and hop plants. The investigation was conducted in Backa Palanka region (Yugoslavia). The intensity of European corn borer on experimental plants was varying not only between plants but also between years.The greatest number of egg issues was 6,28 per 1 plant and the most compacted population of these pests was 5,18 on corn, while on help the number of egg issues was 5,67 and 4,86 caterpillars per 1 plant. It was noticed the depandance between number of layed eggs and compastness of the European corn borer population and T-evanescens effect. During one year (1975) was evidented the distinct effect of T-evanescens (2,93 parasited eggs). The first layed European corn borer eggs on corn and hemp at the end of second decade of June were not at that time parasited. At the time was passing the percentage of parasitivism was increasing. During June it was noticed the increased egg parasitism which was at the middle of process of laying eggs. At the end of butterfly fight, in the begining of August 1975 it was noticed the maximum of parasitive effect (about 15%). The noticable low effect was registered on the European corn borer layed on hemp. T-evanescens rarely parasited all eggs in brood, and a number of it was left unparasited.
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