SUSCEPTIBILITY OF LAMBDINA FISCELLARIA SOMNIARIA (HULST) (GEOMETRIDAE) AND LAMBDINA FISCELLARIA LUGUBROSA (HULST) (GEOMETRIDAE) TO VIRUSES FROM SEVERAL SPECIES OF LEPIDOPTEROUS INSECTS

Fifteen nuclear-polyhedrosis viruses and one granulosis virus were tested against two closely related insects, the oak looper, Lambdina fiscellaria somniaria (Hulst), and the hemlock looper, Lambdina fiscellaria lugubrosa (Hulst). The polyhedrosis viruses from the two insects were highly infectious for each species of host. Viruses from the tussock moth, Orgyia pseudotsugata McD., and the grey forest looper, Caripeta divisata Walker, were, respectively, highly and moderately infectious for the two subspecies. Viruses from five other insects including the California oakworm were poorly infectious for L. f. somniaria.All polyhedra retained their normal shape but nearly all increased in size when passed through the new hosts. All polyhedra (original and transferred) were easily stained with naphthol yellow S and with Buffalo black but only those from C. divisata were stained with Loeffler"s methylene blue. The length of the virus rods of viruses tested was not changed by passage through a new host but the width of three viruses increased.