Last week, Gary Forrester (Horry County Horticulture Agent) found colorado potato beetle larvae in a small field of potatoes in Horry County. Colorado potato beetles, often referred to as potato bugs, can certainly be a pest in the garden.
“Overwintering beetles hibernate in the soil, emerging in the spring about the time that potatoes come through the ground. They lay orange-yellow eggs in groups of a dozen or more on the undersides of the leaves. Each female deposits approximately 500 eggs over a five-week period. Eggs hatch in a few days and the dark red larvae devour the foliage, becoming orange as maturity approaches. There are two rows of conspicuous black dots on the sides of their bodies. When mature, they leave the plant, enter the soil and pupate, emerging as adults several days later. The life cycle requires about a month, and there are one to three generations per year. Injury is due to actual consumption of foliage and stems by adults and larvae, however, potato plants can lose up to 30% of their foliage without a loss of yield.”
“Over the years, it has become resistant to most pesticides and is a major potato pest. A 3- to 5-inch layer of straw added just before the potatoes emerged can lead to higher yields. Soil temperatures will be cooler, soil moisture levels higher, and the populations of Colorado potato beetles will be lower in mulched gardens. Hand picking beetles and larvae, and removing leaves with egg clusters both can reduce the population significantly. The assassin bug is a beneficial predator that will help control the larvae of the Colorado potato beetle.”
Potato bugs don’t just feed on potatoes, they are also a pest of tomatoes and eggplant. For more information on the colorado potato beetle and pesticide recommendations, check out Clemson’s HGIC Fact Sheet or contact your local extension agent.