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.

Control of the larva of the sugarcane rootstalk borer, Diaprepes abbreviatus (L), with the entomogenous nematode Neoaplectana carpocapsae Weiser

In a series of greenhouse tests to determine the susceptibility of the larval stage of the curculionid Diaprepes abbreviatus to the entomogenous nematode Neoaplectana carpocapsae, the nematodes controlled the insect larvae. Grubs 1.5 to 3 months old (smaller than one inch long) were less vulnerable to death than older 3- to 4-month-old grubs. The highest grub mortality, 86.66%, was obtained with the nematode density of 40,000 nematodes per pot. When nematode density was increased from 40,000 to 400,000 nematodes per pot grub mortality did not increase. Grubs placed in direct contact with nematodes in petri plates were equally killed, independently of the nematode density used. Direct nematode inoculation through grub's mouth, anus or a combination of mouth and anus or steeped in water containing nematodes did not increase grub mortality beyond that already obtained in the soil. If similar results are obtained in the field, this method of control could be of great value to reduce D. abbreviatus populations.