PESTS OF PEANUTS
North Carolina Cooperative Extension
Extracted from INSECT and related PESTS of FIELD CROPS (AG-271)
Placed on the Web 10/94 by the Center for Integrated Pest Management, NCSU
In 1980, peanuts were planted on 68,016 hectares (168,000
acres) of North Carolina farm land. Since all parts of the peanut
plant are attacked by an array of pests, peanut farmers must be
constantly on the lookout for insect and mite problems. It is
impossible to predict what problems a grower will encounter in a
given year due to variation in cultural practices, weather
conditions and other factors. The following pests, however, are
most likely to be encountered in North Carolina though perhaps not
in every field every year.
Key to Peanut Pests
A. Chewing insects that consume above-ground plant parts
- Caterpillars - These soft-bodied, moth larvae have
three pairs of legs near the head and four or five pairs of prolegs
(Fig. 1A and B).
- Armyworms - These variously colored
caterpillars have five pairs of prolegs (Fig. 1B), are
occasionally foliage pests, and are difficult to chemically
- Beet armyworm -
Dark-headed (Fig. 2B) and green or black, this larva sometimes has three
longitudinal, light stripes and usually grows about 25 to 30 mm
long. A small, black spot, located above the second leg behind the
head (arrow), occurs on each side of the body (Fig. 2A). Heavily
infested plants may be skeletonized. Young larvae often web leaves
- Fall armyworm - Green, brown, or
black, this caterpillar reaches a maximum length of 30 to 40 mm and
often has a distinct, inverted "Y" (Fig. 2C). The worms
sometimes appear in large numbers in August and September.
- Corn earworm - When fully grown, this larva
is green, reddish, or brown with pale longitudinal stripes and
scattered, black spots. Early instars are fuzzy, cream colored or
yellowish green with few markings. Larval instars vary from 1.5 to
44 mm in length and have five pairs of prolegs (Fig. 1B).
Earworms feed on leaves, stems, and occasionally pegs.
- Cutworms - These chunky, sluggish
caterpillars are active primarily at night; they feed on foliage
and occasionally pods. They have five pairs of prolegs.
- Black cutworm - Varying from light
gray to black in color and often appearing greasy, this caterpillar
grows from 3.5 to 46 mm in length. The skin of this cutworm is
granulated, the granules resembling rounded, flattened pebbles
Granulate cutworm - Growing from 2 to
38 mm long, this caterpillar has a pale brown head, a dark brown
band down its back, and brown sides with faint stripes. The skin
granules of this cutworm are like blunt cones as high as they are
wide (Fig. 3B).
- Green cloverworm - This pale caterpillar,
15 to 30.5 mm in length, is distinguished from all other
caterpillar pests of peanuts by the presence of only four pairs of
prolegs (Fig. 1A).
Velvetbean caterpillar - This pale green to
black caterpillar has a light stripe along both sides of its body.
It has five pairs of prolegs (Fig. 1B), varies from 2.5 to 48 mm
long, and wiggles rapidly when disturbed. During September or
early October, this caterpillar may attack both terminal buds and
- Spotted cucumber beetle - About 6 mm long, this
yellowish-green beetle has black legs, antennae, and head as well
as 12 black spots on its back (Fig. 4). The beetle feeds on
unopened leaflets. As leaflets open, they are riddled with oblong
or irregularly shaped holes.
B. Piercing-sucking pests which feed on above-ground plant parts
(Fig. 5A to D).
C. Insects that feed below ground.
- Cowpea aphid - This small, pear-shaped insect
(Fig. 5) is no longer than 2 mm. The adult of this species is
black with white appendages. The nymph is pale gray with a powdery
coating. This insect feeds in colonies on the underside of leaves,
causing the foliage to turn yellow and also excretes a sweet,
sticky substance known as "honeydew." Black sooty mold often grows
on the surface of this excretion.
- Potato leafhopper -
This tiny, 3 mm long,
yellowish- to pale-green insect (Fig. 5B) has yellow or dark
green spots which can be observed under magnification. It feeds on
the underside of leaves, causing a yellowing from the leaf tip back
- Tobacco thrips - Slender,
about 1 mm long, this tiny insect (Fig. 5C) rasps leaves and
causes them to pucker and lose color.
- Twospotted spider mite - Almost microscopic, this
yellowish- to dark-green mite has two or four dark spots on its
back (Fig. 5D). It has eight legs as an adult, but only six legs
as a larva. It feeds on the underside of leaves, causing the
foliage to turn silver-gray. Webs may be noticeable if the mites
- Beetle larvae - These larvae have three pairs of
short legs near their head (Fig. 6).
- Southern corn rootworm - About 15 to 16 mm
long when fully grown, this beetle larva (Fig. 6A) is yellowish-
white with a wrinkled body. It has a hardened, brown shield over
its last abdominal segment. Most injurious in heavy, poorly drained
soils or following winter cover crops, this pest bores into young
pods or attacks pegs before pods develop.
- Wireworms -
Ranging from a few millimeters
in length to 24 mm when fully grown, several species of these
slender larvae (Fig. 6B) feed within the underground plant parts
of the peanut. Infested plants become yellow and less
- Lesser cornstalk borer - Slender, bluish-green,
and brown-striped, this caterpillar has brown rings around its
body. It is about 19 mm long when fully grown. It may feed
externally or tunnel into underground plant parts. Developing nuts
are often hollowed out.