SELECTION OF INSECT PARASITIC NEMATODES FOR BIOLOGICAL-CONTROL OF THEGARDEN CHAFER, PHYLLOPERTHA-HORTICOLA

Larvae of Phyllopertha horticola L. (Coleoptera: Scarabaeidae) cause i ncreasing problems on sports fields and lawns in NW-Europe. A biologic al control programme using insect parasitic nematodes is being develop ed. This paper contains the results of bioassays with various species and isolates of the nematode genera Heterorhabditis and Steinernema. I n bioassays in small pots with moist sand, most of the nematode isolat es gave 30-60% mortality against each of the three larval stages. The susceptibility of the grubs for nematode infection generally increased with larval development. H. bacteriophora, H. heliothidis, H. megidis , a Dutch Heterorhabditis isolate NLH-E87.3 and S. glaseri 326 showed the highest mortality rates, with nearly 100% mortality of third insta r grubs. The Dutch Hetevorhabditis isolate NLH-E87.3 and S. glaseri 32 6 were selected as candidates for further studies on their potential a s biological control agents for P. horticola grubs in the field.