Everyone understands that a dairy cow needs food, water, shelter and protection from adverse conditions. To perform her best she also needs protection from biting flies, diseases and in some cases, predators which may injure or kill her. The dairy producer knows her requirements change through the year and makes provisions to provide for these needs. In the winter, shelter is critical, while in the summer adequate water and shade are necessary. In some months, grazing may provide her total food requirements, but as pasture growth slows, supplemental food may need to be provided.
Natural enemies have exactly the same types of needs as the dairy cow.
To perform their best, they need food, shelter and protection from adverse conditions as well. Frequently, we do not fully understand or make allowances to provide for these needs. The result is many instances where biological control could be very effective, but has failed or resulted in less than adequate control because we did not provide for the natural enemies' basic requirements. Avoid Harmful Practices. The most obvious practice to avoid is the use of insecticides at times when natural enemies will be harmed.