Sevin, a great new insecticide for the home vegetable garden? Experienced vegetable gardeners may well question this statement. After all, Sevin has been used in home vegetable gardens across the country for decades. You may even recall your grandfather using it in his garden, along with malathion for the insects the Sevin did not control, and a lot of productive gardens have been grown over the years using only these two insecticides. However, this original formulation of Sevin contained carbaryl as the active ingredient, and the preharvest interval for carbaryl can be quite long, ranging from 3 to 14 days depending on the crop being treated. Three days is too long to wait to have to wait to pick zucchini, and it’s a bit trying for tomatoes.
This year, GardenTech has introduced a new formulation of Sevin, called GardenTech Sevin Insect Killer Concentrate, which contains zeta-cypermethrin as the active ingredient. This is great news for home vegetable gardeners because zeta-cypermethrin has two key advantages over carbaryl: it is more effective against a wider range of insect pests and it has much shorter preharvest intervals (PHI) on most vegetable crops.
In fact, this new formulation of Sevin has a 1 day PHI on all fruiting vegetables—including tomatoes, pepper and okra; cucurbits, such as squash, pumpkins and melons; brassica, such as broccoli and cauliflower; leafy vegetables—including lettuce, mustard greens and bok choy; succulent beans and peas; and root and tuber vegetables, like turnips and Irish potatoes. This is a product that will control most insect pests in the home vegetable garden and can be used on most crops in the garden with a 1 day PHI. But be sure to read the label carefully, because there are some pests it does not control, like aphids, spider mites and whiteflies, and there are some crops, like corn, peanuts and sunflowers, with longer PHIs.
Unfortunately, this is going to cause a good bit of confusion, because there are still many Sevin products, including some GardenTech products, as well as Sevin products from other companies, that contain carbaryl as the active ingredient. Read labels carefully before purchase to be sure you are getting the product you want. Read the label again before mixing and treating.
Note that even though GardenTech Sevin Insect Killer Concentrate contains only 0.35% zeta-cypermethrin, this is a concentrate and must be diluted with water before treating. The old formulation of liquid Sevin contained 22.5% carbaryl. But this apparent discrepancy in concentrations of active ingredients is not cause for concern, because these are two different types of chemistry. Zeta-cypermethrin is a pyrethroid insecticide and is effective at much lower doses than carbaryl.
See Extension Publication 2347, Insect Pests of the Home Vegetable Garden, for more information about vegetable insect pests and how to control them.
This new, zeta-cypermethrin formulation of Sevin has not yet been added to this publication, but zeta-cypermethrin will be effective on any pests that are controlled by other pyrethroids, such as permethrin or bifenthrin.
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.
The information given here is for educational purposes only. Always read and follow current label directions. Specific commercial products are mentioned as examples only and reference to specific products or trade names is made with the understanding that no discrimination is intended to other products that may also be suitable and appropriately labeled.