INSECT PESTS OF INSECT PESTS OF POTATOPOTATO•Potatoes are attacked by most of the insects which infest closely related solanaceous plants like tomato, eggplant, and pepper. •However, since potatoes are grown for their edible tubers, they must receive greater protection from soil-inhabiting pests. •Wireworms, tuberworms, white grubs, and vegetable weevils are pests for which growers should watch.

KEY TO POTATO PESTSKEY TO POTATO PESTSA. Pests that feed externally on the

upper plant1. Chewing pests that make holes in leaves :

Blister beetles, Colorado potato beetle, Flea beetles

2. Sap-sucking pests that cause discoloration, deformation, or abscission

B. Pests that feed on underground plant parts, bore into stems, or mine in leaves and petioles

Chewing pests Chewing pests Blister beetles Blister beetles Several species of slender, elongate

beetles up to 19 mm long; have prominent heads; bodies variously colored but usually black, black with yellow margins, or black and yellow striped; stringy black excrement on heavily infested plants; foliage ragged; plants sometimes stunted

Colorado potato beetleColorado potato beetleYellowish-brown, oval, convex beetle up

to 14 mm long with 5 black longitudinal stripes on each wing cover and several black spots on pronotum (area behind the head) feeds on leaves and terminal growth

Flea beetlesFlea beetlesVarious species of tiny, darkly colored

beetles 2.5 to 4.5 mm long; solid-color body or dark with pale yellow stripe on each wing cover tiny round holes in foliage

Sap-sucking pests Sap-sucking pests AphidsAphidsSoft-bodied, pear-shaped insects with

a pair of dark cornicles and a cauda protruding from the abdomen; may be winged or wingless - wingless forms most common; feed in colonies; cause discoloration or mottling of the foliage; often transmit virus diseases; excrete honeydew on which sooty mold grows

Green peach aphid, Potato aphid

Green peach aphidGreen peach aphidPale yellow to green, wingless adult up

to 2.4 mm long; winged adult with dark dorsal blotch on yellowish-green abdomen; cornicles over twice as long as cauda and slightly swollen toward tip; yellow-green nymphs with 3 dark lines on abdomen

Potato aphidPotato aphidAdult and nymph both solid pink, green

and pink mottled, or light green with dark stripe; adult up to 3.5 mm long; long slender cornicles about twice as long as cauda

Potato leafhopperPotato leafhopperSpindle-shaped pest, up to 3 mm long;

green body with yellowish to dark green spots usually jumps instead of flies; extracts sap from underside of leaf causing leaf to crinkle and curl upward; also causes yellowing of leaf tips and margins (hopperburn)

European corn borerEuropean corn borerCream to light pink caterpillar with

reddish-brown to black head; body up to 26 mm long with several rows of dark spots; has 3 pairs of legs near head and 5 pairs of prolegs bores into stem; tangled frass and silk near entrance hole; stem may break, plant may yellow or wilt readily

Potato tuberwormPotato tuberwormCreamy white (young) or green to pink

(mature) caterpillar up to 19 mm long with dark brown head; 3 pairs of legs near head and 5 pairs of prolegs mines in older lower leaves causing grayish papery blotches; tunnels in exposed tubers or those close to soil surface, filling tunnels with excrement; entrance holes usually near the eyes and surrounded by a pink coloration

Vegetable weevil and Vegetable weevil and larvalarvaAdult - dull grayish-brown weevil, about 6.4

mm long, with short, stout snout and light V-shaped mark on wing covers larva - pale green, legless, up to 10 mm long, with dark mottled head both feed at night making large open holes in surface of potatoes. Feeds primarily at night on underground plant parts, but sometimes consumes buds and foliage

White grubsWhite grubsSeveral species of creamy white grubs

with a distinct brown head capsule, three pairs of legs near the head, and slightly enlarged abdomen; body C-shaped and up to 50 mm long sever roots and stems of potatoes; leave large, shallow circular holes in tubers

WirewormsWirewormsSeveral species of slender, wire-like

larvae with three pairs of short legs near the head and a pair of prolegs at the tip of the abdomen; large shallow cavities in sweet potatoes - evidence of early injury; deep ragged holes - later injury

Melanotus communisSouthern potato wirewormTobacco wireworm

Melanotus communisMelanotus communisYellowish-brown with darker head;

body up to 25 mm long; last abdominal segment with scalloped edges

Southern potato Southern potato wirewormwirewormCream colored or yellowish-gray with

reddish-orange head; body up to 17 mm long; oval notch in last abdominal segment

Tobacco wirewormTobacco wirewormWhite with brown head; body up to 19

mm long; V-shaped notch in last abdosssssminal segment