• Trial, Henry Jr
  Maine Dept of Conservation
  
• Dimond, John B.
  Maine Dept of Conservation
  

Aerial applications of single and double (split) treatments of several standard and new formulations of Bacillus thuringiensis (8.t.) were evaluated against the spruce budworm infestation eastern Maine in 1986. The most evident result was that double applications of 8 plus B BIU (Billion International Units) per acre were superior to single applications of 8 or 12 BIU. This was particularly evident on red spruce, a host species where good control of spruce budworm is often difficult to achieve. The highly concentrated formulations, Dipel 12L and Thuricide 64LV, applied as single applications of 12 BIU per acre did not provide uniformly favorable results. No difference was seen in efficacy between two variations of the formulation of Dipel 8L.