Comparative field stability of selected entomopathogenic virus formulations

Nucleopolyhedroviruses originally isolated from Anagrapha falcifera (Kirby) and Autographa californica (Speyer) were formulated with various ingredien ts using a spray dry method and tested for residual field activity in Illin ois and Mississippi. In Mississippi, field tests were conducted on cotton i n 1997, whereas in Illinois tests were conducted on cabbage in 1997 and 199 8. Within 24 h, significant differences were observed among formulations in all tests. Unformulated virus had significantly less insecticidal activity than formulated virus and formulations containing lignin retained activity significantly longer than other formulations. Relatively small-amounts of Blankopbor BBH, when encapsulated within the formulation, did not greatly e nhance (> IOX) insecticidal activity based on LC50 determinations nor prolo ng insecticidal activity based on field evaluations. In most tests, > 50% a ctivity remained in formulations containing lignin, whereas unformulated vi rus retained < 50% activity within 24 h after application.