Effects of ultraviolet radiation and sunlight on the entomogenous nematode, Neoaplectana carpocapsae

Infective-stage juveniles of Neoaplectana carpocapsae were acutely sensitive to short uv radiation (254 nm) and natural sunlight. High nematode mortality, although delayed, accompanied uv exposure. Irradiation rapidly reduced nematode pathogenicity, so that nematodes exposed for 7 min were unable to cause lethal infections in Galleria mellonelia larvae. Moreover, the median survival time of Galleria larvae increased progressively as nematode exposure to uv was lengthened. Inhibition of nematode reproduction and development was noted at exposure periods longer than 2.45 and 5 min, respectively. However, irradiation did not appear to affect juvenile motility. Exposure to direct sunlight also reduced pathogenicity, in a range from 6.9 to 94.9% at 30 and 60 min of exposure, respectively. Long uv (366 nm) did not affect juveniles at the exposures tested.