The Re-isolation of Neoaplectana bibionis Bovien (Nematodea) from Danish Bibionids (Diptera) and Their Possible Use as Biological Control Agents

In. the spring of I97I, Neoaplectana bibionis Bovien was re-isolated from larvae and pupae of Bibio hortulanus L. and other bibionids from 3 localities in Denmark. Third stage infective larvae were recovered and used to initiate laboratory cultures. When nematodes were injected into the mouth of the greater wax moth larvae, Galleria mellonella L., they quickly penetrated into the hemocoel of the living insects and brought about their death. Successive nematode generations also occurred on artificial media used for rearing Neoaplectana carpocapsae Weiser. A specific rod-shaped bacterium was isolated from the intestine of infective stage larvae and probably has the same relationship to the nematode as N. carpocapsae has to its symbiotic bacterium, Achromobacter nematophilus. This nematode may make an excellent candidate for biological control programs involving soil insects.

Biocontrol of the banana root borer weevil, Cosmopolites sordidus (Germar), with Steinernemotid nematodes

The entomogenous nematodes Steinernema feltiae Filipjev ( = Neoaplectana carpocapsae Weiser), S. glaseri Steiner, and S. bibionis Bobien (Steinernematidae: Rhabditida) were evaluated as biological control agents against the banana root borer weevil Cosmopolites sordidus. In the grub stage this weevil bore tunnels in the corms of plantains thereby promoting infection and plant decay. In petri-dish trials the three species produced severe mortality at population densities of 4,000 and 40,000 nematodes. Similarly, in greenhouse tests, the three nematode species at rates of 400, 4,000, and 40,000 nematodes/4-month-old plants apparently reduced the number of tunnels produced by the grub. Grub mortality was 100% at nematode populations of 4,000 and 40,000 per plant.