VIRULENCE OF ENTOMOPATHOGENIC NEMATODES (NEMATA: RHABDITIDA) AGAINST LARVA OF THE FUNGUS GNAT BRADYSIA MABIUSI (LANE, 1959) AND PERSISTENCE OF HETERORHABDITIS INDICA POINAR ET AL. 1992 ON ORGANIC SUBSTRATES

ABSTRACT

The virulence of four entomopathogenic nematodes strains against Bradysia mabiusi (Lane) 3º – 4º instar larvae in laboratory conditions and the persistence of Heterorhabditis indica Poinar et al. 1992 on organic substrates, in the greenhouse, were evaluated. For the virulence test, four nematodes strains were used: Heterorhabditis indica IBCB-n05, Heterorhabditis sp. IBCB-n10, Steinernema glaseri CCA and S. carpocapsae CCA. These nematodes were evaluated at the dosage of 200 infective juveniles (IJ)/ larvae. For the persistence study, the nematode H. indica was selected and two tests were carried out. In the first test, the nematode was applied at the dosages of 5.7 and 22.6 IJ/cm², and in the second, at the dosages of 10 and 50 IJ/cm². For both tests, two evaluations were done, releasing insect larvae on the treated and nontreated substrate at 24 hours and 15 days after the application. The nematode H. indica IBCB-n05 was the most virulent, causing 100% mortality of larvae, but did not differ statistically from Heterorhabditis sp. IBCB-n10 and S. carpocapsae(96% and 83% mortality, respectively). For the first persistence test, H. indica IBCB-n05 at the dosages of 5.7 and 22.6 IJ/cm² afforded, respectively, 67 and 80% mortality of larva (corrected by Abott’s formula) 24 hours after the application. For the other persistence test, the nematode at the dosages of 10 and 50 IJ/cm² afforded, respectively, 69 and 97% mortality (corrected by Abott’s formula) 24 hs after application. The persistence of the neiological control, Sciaridae, Steinernema sp., Heterorhabditis sp., Bradysia mabiusi.

KEY WORDS
Biological control; Sciaridae; Steinernema sp.; Heterorhabditis sp.; Bradysia mabiusi