"1) treat infested trees with a foliar spray. The two products that we have evaluated are Talstar (a pyrethroid insecticide) or Dipel (a microbial insecticide).
"Talstar is very fast acting, gave us near 100% control, controls all sizes of caterpillars, and we got at least a week's residual from a single application. One application should do the job now that all of the egg masses have hatched."Dipel (Bacillus thuringiensis) gave us decent control (75% or so). It was quite effective against the small larvae but less so against the large ones. Its residues do not last as long as Talstar's.
"2) inject the trees with bidrin (Inject-a-cide B) within the next week. We found that this was quite effective so long as the larvae were less than half their full size. The injection must be done by the Mauget system by a certified applicator."