Follow label directions for garden product use
STARKVILLE, Miss. -- Mississippi’s ideal growing season means gardens can yield a lot of produce, but this usually comes with the help of pesticides to combat insects and diseases.
It is vital that home gardeners know how much time must elapse between application of the product and when the food is harvested, a time frame known as the pre-harvest interval, or PHI.
Jeff Wilson, horticulture specialist with the Mississippi State University Extension Service, said this information is found on the label of any product intended for use on an edible crop.
“For some products on some crops, the wait is very short, and you can use a product up to the day of harvest,” Wilson said. “For other products, the wait can be as much as 21 days or even longer.”
Wilson said the pre-harvest interval for a garden product is rarely the same for all crops in the same garden.
“It depends on what crop is being sprayed,” he said. “For example, the same permethrin spray has a zero-day PHI on tomatoes, a one-day PHI on lettuce, a three-day PHI on peppers, a seven-day PHI on potatoes and a 14-day PHI on blueberries.”
Information on correct use of the product as well as the pre-harvest interval is always written on the label. Be sure to read and follow these directions to safely use the product.
“Because it can be complicated to keep up with all this information, home gardeners may find zeta-cypermethrin a good insecticide choice because it controls most major garden insects and has a one-day PHI on most fruiting garden vegetables such as tomatoes, peppers and eggplant,” Wilson said.
The insecticide bifenthrin may be a bit more effective on some pests, but it has a seven-day PHI on peppers and a three-day PHI on squash.
“If you have leaf-footed bugs feeding on the tomatoes and the peppers, and squash bugs on the zucchini, it is helpful to know you can spray them all at the same time and be able to pick all three crops at the same time a day or two later,” he said.
“However, there are some pests, such as aphids, spider mites and whiteflies, that zeta-cypermethrin will not control, and there are crops such as onions and sweet corn for which the PHI for zeta-cypermethrin is longer than one day,” Wilson said.
Rebecca Melanson, Extension plant pathologist, said the label is the law.
“Users are legally required to follow the product label,” Melanson said. “The label instructions, limits and prohibitions are provided to ensure the safety of the food supply and the users while minimizing impact to the environment and non-target pests.”
The MSU Extension Service has a variety of information available to home gardeners and commercial operations. Publication 2347, Insect Pests of the Home Vegetable Garden, is quite comprehensive, and other publications are available by topic search at .
