BLANKOPHOR BBH AS AN ENHANCER OF NUCLEAR POLYHEDROSIS-VIRUS IN ARBORIST TREATMENTS AGAINST THE GYPSY-MOTH (LEPIDOPTERA, LYMANTRIIDAE)

Doses of a commercial candidate formulation of gypsy moth nuclear poly hedrosis virus (LdMNPV) were applied with and without several concentr ations of an enhancing adjuvant, Blankophor BBH, to individual trees a gainst natural gypsy moth, Lymantria dispar (L.), populations. Amounts of Blankophor BBH adhering to foliage after application were measured at 1,322, 227, and 37 mu g/g dry weight of leaf for the 0.5, 0.1, and 0.02% treatments, respectively. The highest dose of the candidate for mulation used without the adjuvant failed to increase significantly 1s t-generation after-treatment LdMNPV mortality (direct infection caused by feeding on applied virus) above background levels, to reduce late season (instars 5 and 6) larval populations in treated trees or to pro vide significant foliage protection. However, Blankophor BBH added to the tank mix at concentrations of 0.5 or 0.1% (wt:vol) resulted in sig nificantly increased levels of 1st-generation after-treatment LdMNPV, significantly reduced late-season larval populations, and significant levels of foliage protection, compared with untreated control trees. T he resulting recommended tank mix (0.1% Blankophor BBH and 2x 10(10) P IBs per 75 liters final spray solution per tree) should give excellent foliage protection against gypsy moth at a cost of about $3 per tree.