IMPROVED FORMULATIONS OF HELIOTHIS NUCLEAR POLYHEDROSIS-VIRUS

New formulations of the Heliothis nuclear polyhedrosis virus were made by incorporating the pathogen with UV light screening agents in a capsule bound together with digestible, water-insoluble polymers. Bioassays demonstrated that 2 of these, one made with titanium dioxide and the other with carbon black, were remarkably tolerant of the UV irradiation of germicidal lamps in the laboratory and of sunlight in the field; effective biological activity was preserved for periods well in excess of those of commercial virus formulations used for comparisons. In field tests against moderate populations of Heliothis spp. in cotton, yields of plots treated with these formulations were statistically identical to those of plots treated with the insecticide mixture commonly used in commercial production; yields of all treated plots were significantly greater than those of untreated plots.