Badania nad nicieniami pasożytami owadów

In Poland, investigations of nematode parasites of insects had not been carried out at all. The present study is aimed at gaining information on the parasitic nematofauna of the most common insect pests and on its influence on the abundance of the latter. We have taken the term parasitic nematofauna to mean nematodes living in the body of insects - whatever the type of relation with the host. More than 10000 examinations of insect pests, carried out in the years 1965-1966 have disclosed the existence of nematodes in their bodies. Analyses of grubs Melotontha sp.) and of adult forms of Colorado beetle were of greatest interest. It was found that some of the grubs were greatly infested with nematodes, chiefly with Cephalobellus papilliger Cobb (Thelastomatidae) although no harm was inflicted on the hostes by the nematodes. Several examinations of adult hibernating Colorado beetles revealed that most of them were infested with nematodes belonging to the Diplogasteridae family. All infested Colorado beetles perished in a short time. We have worked out a method for culturing this species of nematodes on artificial media. Moreover attempts at biological control of Colorado beetle were made by spraying the beetles with a water suspension of nematodes. The results were successful and this method may prove of use in insect control. Numerous summertime post-mortem examinations of larvae and adult forms of Colorado beetle have revealed that in the southern regions of Poland nematodes belonging to the Mermithidae family, play an essential role in reducing the abundance of Colorado beetle.