Everything You Wanted to Know About Biological Controls... But Were Afraid to Ask
by Liz Felter Multi-County Extension Agent
Biological control, predators, parasites, IPM -- where do you begin when starting an environmentally friendly pest control program?
You begin by "scouting" the plants in your production area. Scouting means to walk the nursery or greenhouse looking for plants that appear different from the norm. The scout should look for leaf spots, insect damage, spray burn, and the presence of natural predators and parasites. Predators and parasites are known as "beneficial" insects: good bugs that eat the bad bugs. Predators hunt and feed on pests; the praying mantis and the lady beetle (ladybug) are common examples. Parasites are born inside or on a pest, and they eat the pest as they grow; common parasites are various wasps.
Records should be kept identifying the areas where the afflicted plants are found, so the information can be reported to the grower/manager.
Scouting is an integral part of an integrated pest management program. This program should also include good cultural practices. Good plant care, including nutrients, water, and sunlight maintain vigorously growing plants that are less susceptible to pests. Biological controls such as beneficial insects, friendly fungus, insect growth regulators, and soap and oil sprays should be tried before resorting to chemical pesticides.
Some of the most commonly asked questions are: What can you expect from a biological control program? What changes in growing practices will occur? Will there be failures? Is help available? How much knowledge is needed to start an IPM program, and is it costly?
Growers should expect a lot of trial and error. An effective IPM program has to be customized to fit each individual nursery or greenhouse. Each grower and owner has to agree on what is an acceptable level of pests before having to treat with soap and oil sprays or "soft" chemical pesticides. The spray program is the biggest practice change. Improper selection and timing of pesticide application and their residuals are a major cause of failure in a biological control program.
You don't have to be an IPM expert: you do have to know which pest problems exist at your nursery. Help and support is available from your County Cooperative Extension Service horticulture agent, extension specialists, and private IPM consultants, as well as many of the companies that supply beneficials. Analysis shows a potential of a 30 - 60% cost decrease when compared to a traditional spray program. However, each nursery is different and costs vary with particular management practices.
In the beginning, while the requisite knowledge about pests is being developed, costs may be high. However, as knowledge increases and scouting and suppression become more efficient, costs will decrease. The savings, combined with a reduction in liabilities from using less chemicals and a diligent patient approach, make IPM a desirable production program.