I sprayed my box hedge with Btk in full midday sun just to hit the caterpillars early: three days later, what was still chewing the leaves wasn’t a new wave
You sprayed Btk at noon and three days later, caterpillars were still chewing your boxwood hedge. It wasn’t a new infestation—it was predictable failure caused by UV degradation, wrong timing, and caterpillars hiding in silk nests. Here’s exactly what went wrong and how to fix it.