I have honeybees at my dad's house. He wants to spray his fruit trees with Bonide complete tree spray. I don't think I can talk him out of it. Is there any way to minimize the damage? I told him he needs to mow so there are no dandelions or anything they are foraging on anywhere near, and to do it at night.
The first publication that I recommend is the OSU Extension publication, Managing Diseases and Insects in Home Orchards. This publication contains a wealth of information to help the home gardeners control insect and pest damage to the point that they are able to harvest usable fruit. There are several options for individual problems rather than an all in one spray like Bonide Tree Spray which contains multiple pesticides combined into one spray. Perhaps not all are needed to address the problem with your dad’s orchard and a less toxic product could be used instead.
Bonide Complete Tree Spray contains 11.76% Captan, which is a fungicide, there are no bee precautions listed for that ingredient. Next at .3% is Carbaryl, an insecticide, which is highly toxic to bees and is hazardous to bees when applied to blooming trees. The third listed ingredient at 6% is Malathion, another insecticide, which is also highly toxic to bees. Depending on the formulation, it can have up to a 5.5 day extended residual toxicity for bees. This information is contained in OSU Extension’s How to Reduce Bee Poisoning from Pesticides. On pages 8-14 of this publication, several steps are listed that can be taken both by the beekeeper and by the pesticide applicator to protect bees. One of the big steps is to mow blooming weeds under trees before spraying. You also might consider moving the hive during the spray season. It looks like it is supposed to be sprayed only twice a growing season.
Above all else, the label is the law, so read and follow the label directions.