Acephate is particularly problematic because it has a long residual effect, from one to three days. This raises the concern of thrips control. Since this coincides with increased bee activity in the rose garden, I am rethinking the use of acephate with its long residual period. Dick Streeper, in an article in the June 1997 American Rose, mentioned returning to malathion for thips control. Since malathion has a potentially shorter residual period, it becomes my product of choice.
Spider mites are also problematic.
Outbreaks of spider mites tend to occur in hot weather, when bee activity also increases. New Pesticides New pesticides are reaching the marketplace, at least for commercial application, under Federal initiatives to find alternatives to organophosphates. Many of these new pesticides are derivatives of bacteria, fungi, protozoa and viruses. They vary in their toxicity to bees. However, a conversation from a company representative said the label wording was required because a bee toxicity study had not been done.