Using fewer insecticides improves crop yield by increasing pollination by bees

65 The vast majority of farmers use chemical insecticides to protect their crops against potentially damaging insect pests. This should not be a foreign concept to beekeepers; the majority of beekeepers use miticides to protect their bees against the varroa mite. But how farmers use insecticides varies greatly. Some farmers operate on a schedule, applying insecticides every month or so to prevent pest problems from occurring. When insecticides are cheap and pests are a consistent threat, this can be an effective strategy.* Conversely, some farmers use Integrated Pest Management (IPM) to decide when to use insecticides. A cornerstone of IPM is monitoring for pests and only using insecticides when pest populations or damage from those pests reaches a predetermined economic threshold. In this way, insecticides are only used when necessary, which saves money and reduces unnecessary pesticide inputs to the environment. To continue with the varroa analogy, if you monitor for varroa levels in your colonies and only treat with miticides when levels are above a predetermined threshold, you are practicing IPM. When a crop relies on insects for pollination, another potentially important economic benefit of IPM exists. By using fewer insecticides, insect pollinators are less likely to be harmed, which could translate into better pollination, improved crop yield, and greater economic returns for a farmer. This all sounds good in theory, but is there real-world evidence that practicing IPM and using fewer insecticides can improve yield in a pollination-dependent crop? If so, is increased yield due to greater numbers of bee pollinators? And what about a crop that doesn’t rely on pollinators? Can farmers improve their bottom line by taking an IPM approach, or will they frequently surpass economic thresholds such that impacts on yield occur? These are the topics for our forty-ninth Notes from the Lab, where we summarize “IPM reby Scott McArt