Everyone knows that pollinators, including but not limited to honey bees, are important for the production of fruit crops. A big topic in recent years has been the stresses that reduce honey bee populations. Although not most important, pesticides are one factor that can reduce the populations of pollinators. Here are some things fruit growers can do to minimize the negative impacts of pesticides on pollinators.
- Read and Follow Insecticide Labels
Insecticide labels contain specific instructions to help you reduce risks. All insecticides that are toxic to bees have warnings on the label. These warnings are often hard to find on some older insecticide labels. However, many newer insecticides have special bee icons on their labels that draw attention to the potential for harm to pollinators. They often have specific instructions for minimizing the risk.
- Follow IPM Principles
Integrated Pest Management (IPM) is a system that combines different methods to keep pest populations low while allowing for profitable production and minimizing adverse environmental effects. To reduce the risk of harming pollinators, IPM principles guide producers to take advantage of non-insecticidal practices that can reduce pest damage. Oil sprays, conservation of natural enemies, planting disease resistant cultivars and rootstocks, and proper tree pruning and training are examples of non-chemical approaches
Make sure that you know the target pest when you make an insecticide application. When deciding whether to apply an insecticide, determine if the net profit from applying the insecticide is greater than the cost of applying it. Making an informed decision usually involves scouting your field or orchard to determine the level of pests that are present. It doesn’t make good sense to spend $50 per acre to avoid $30 per acre in losses. Using IPM principles will often reduce the amount of insecticides you need to apply.
- Register with DriftWatch
The DriftWatch website (driftwatch.org) is a place where specialty crop producers can register their production sites on a map. Pesticide applicators can access this data before applying anything to nearby fields. The rationale behind this site is to provide applicators with the locations of sensitive sites, so they can take precautions to avoid overspray or drift to locations where they are not wanted.
- Don’t Treat Areas Where Pollinators Visit
For crops that have a very well-defined bloom period, such as most tree fruits, growers should just avoid the use of insecticides during that period of time. For other fruit crops, such as raspberries and blackberries, plants are in bloom over an extended period of time, including when fruit are ripening and need to be protected. Spotted wing drosophila is a good example of a pest that needs to be managed when plants are still blooming. In these situations, growers should make their insecticide applications during the late evening hours after the bees have returned to the hive. The worker bees will still be exposed to insecticide residual the next day, but they will not be directly sprayed and the residue levels will be somewhat reduced when they return.
- Avoid Use of the Most Toxic Insecticides
Not all insecticides are equally toxic to pollinators. When possible, choose the least toxic option that will effectively control the target pests. See the publication “Protecting Honey Bees from Pesticides” at https://extension.entm.purdue.edu/publications/E-53.pdf for a listing of the toxicity levels of many common pesticides. Among the neonicotinoid insecticides that have been implicated in harming pollinators, Assail (acetamiprid) is the least toxic to bees and should be selected preferentially over other members of this class of insecticide.
- Communicate with Your Bee Provider
If you rent bees to pollinate your crops, both you and your beekeeper have a stake in maintain the health of the honey bees. Talk with your beekeeper about the pests that you have to deal with and the need for any insecticides you may apply. Coordinate the arrival and departure of the bees with your insecticide applications to ensure minimize any potential harm to the bees.