SPECIFICITY TESTING OF THE NUCLEAR POLYHEDROSIS-VIRUS OF THE GYPSY-MOTH, LYMANTRIA-DISPAR (L) (LEPIDOPTERA, LYMANTRIIDAE)

An aqueous suspension of the nuclear polyhedrosis virus of Lymantria dispar (L.), LdNPV, was fed to third-instar caterpillars of L. dispar and 46 species of nontarget Lepidoptera in four successive, 24- to 48-h doses of 3 x 10(4) polyhedral inclusion bodies (PIBs) in 2 mu L applied to small pellets of artificial diet or isolated surfaces of foliage. Adults of the fly Cyrtophleba coquilletti Aldr., and adult males of the bee Megachile rotundata (Fabr.), were assayed with a single dose of 1.2 x 10(5) PIBs in 2 mu L Of 30% sucrose solution. Only those specimens that completely consumed the dose(s) were transferred to appropriate maintenance conditions for 7-10 days whereupon they were frozen. Samples of macerates of experimental specimens were dot-blotted onto nylon membranes on which whole genomic LdNPV DNA-probing and chemiluminescence techniques were used to show presence of LdNPV DNA. With reference to positive and negative controls, the 48 nontarget species were diagnosed as nonpermissive of LdNPV but the target species was clearly infected. This study demonstrates a high degree of host-specificity of LdNPV.