Potatoes are a popular garden crop, and are fairly easy to grow. The hardest part of growing potatoes may be keeping the pests off them. The type of insect that affects your potato plants can depend upon the growing zone in which you live, but you can start by looking out for some of the most common pests.
The potato beetle, also known as Colorado potato beetle or potato bug, is the most familiar potato pest. According to a report from the University of Kentucky, it is also the most serious. The potato beetle is black with yellow stripes, and the larva is red with black spots. Both the larvae and the adults will feast on potato leaves, and they can inflict so much damage that they can kill the potato plant. The beetles spend the winter under the soil and emerge in the spring. They lay their eggs on the underside of the potato leaves at the rate of 500-plus eggs during a five week time frame. The larva-to-adult growth phase takes about 21 days. The potato beetle quickly develops a resistance to pesticides. Speak to a lawn and garden expert in your growing area about how to deal with potato beetles.
Aphids are tiny insects that can harm the potato plant in two ways: by sucking the sap out of the plant's leaves and by transmitting diseases to the plant. Signs of aphid leaf trouble are sticky surfaces on potato leaves and leaves that are deformed in shape. Aphids are best kept under control by other insects, such as the ladybug or wasps. Aphids will lay eggs on the potato leaves and stems, where they hatch into larvae and grow into adult aphids.
Leafhoppers, like aphids, also suck the sap out of potato leaves and are usually found on the underside of the leaves. The sign of leafhopper damage is often referred to as "hopperburn," and it is a visible brown spot, shaped like a triangle, at the end of the leaf and the leaf veins. Leafhoppers will lay their eggs along the stems and leaves of the potato plant. The eggs hatch within 10 days, and the larvae become adults within three weeks.
The blister beetle and flea beetle may also attack potato plants, but they are not as common as the potato beetle. Blister beetles can often be found munching on potato leaves, but are not reported to do serious damage to the plant or its yield. Flea beetles spend the winter in the soil and will feed on the underside of the potato leaf, but are considered to be more dangerous to the potato tuber root than the foliage.
The variegated cutworm and western yellow striped army worm will also feed on potato foliage, and can completely destroy the leaves. These "worms" are actually caterpillars, which can be removed before they develop into moths.