Peanut Insect Control
The objectives in peanut production in Mississippi are to obtain maximum yields, hold production costs as low as possible, and produce profits. However, many variables affect peanut production, such as climate, soil type and potential, cultural practices, varietal selection, harvesting, and pests.
Peanuts are damaged by weeds, plant diseases, and insects. The damage varies by year, location of field, and season. Insects alone can cause foliage and pod damage. Where plant diseases, such as tomato spotted wilt, are transmitted by thrips and a high percentage of plants in a field are infected with the virus, yield losses become significant.
You can manage insects by monitoring fields, using economic thresholds, selecting recommended insecticide rates, and properly timing applications.
Scouting
To determine the identity and level of infestation of pests, monitor a field at least once each week for damage and insects. This is called scouting. Inspect each field for soil insects when preparing soil before planting. Where economic infestations of pests, such as white grubs, wireworms, whitefringed beetle larvae, and/or bahiagrass bores are present, apply soil insecticides to the soil before planting.
When sampling a field, select at least 10 random locations. Observe soil and plants for foliage and pod injury. Count insects by briskly shaking plants to dislodge caterpillars on the soil surface. Check row feet at each location when monitoring foliage-feeding caterpillars. To do this, extend arms along two rows and shake one-half of the 3-foot section with each arm into the middle of the rows. Observe and count the number of insects found in the middle.
Scouting Tips and Economic Threshold Information
White grub, Wireworm. There are no data to indicate the number of these pests that cause economic problems. However, if an average of one or more larvae per square foot is present, control is probably justified.
Whitefringed beetle larvae. Larvae feed on underground parts, and if tap roots are cut, plants remain stunted or die. Severe damage often occurs in spots in fields. If you see many adults at the end of a season, then check for larvae in soil before planting the following season. There are few effective insecticides for control of larvae. When you detect adults, apply multiple applications of foliar insecticides to prevent egg laying. Adult control is costly and may not eliminate the problem.
Lesser cornstalk borer.1 To check a field for lesser cornstalk borers and their damage, carefully examine the plants on 3 feet of row, at 10 locations scattered across the field. At each of the locations, lift the plant limbs gently and examine them for soil-covered webs. If you find webs, disintegrate them and look for borers and determine whether damage is fresh. Split plant branches and other damaged parts to look for borers. It may be necessary to reomve some plants from the soil to examine them thoroughly. If you find fresh damage and/or borers at 3 of the 10 locations, apply a recommended insecticide for control.
When checking a peanut field, be alert for lesser cornstalk borer moths and wilted plants or plant parts. However, base your decision on whether to use an insecticide on the presence of the borers and fresh damage only.
Southern corn rootworm.1 This pest is strictly an underground feeder. It may feed on the roots of peanut plants to some extent, but its most important damage is due to peg and pod feeding. Many of the holes cut into pegs and pods will be almost cylindrical, as if they were made by a tiny drill bit. In contrast to lesser cornstalk borer feeding, there is no webbing associated with this pest.
To check for this pest, remove pegs and pods from the soil. It is helpful to remove entire plants. As with the lesser cornstalk borer, check plants on 3 feet of row at 10 locations scattered across the field. Remove one bunch of plants completely from the soil and carefully sift the loose soil that remains. Carefully examine all pegs and pods for feeding damage. If you find fresh damage or rootworms at 3 of the 10 locations, apply a recommended insecticide.
Thrips. When monitoring for thrips use a small box with a white lining, clipboard, or any other material that is light colored and allows plants to be bent across its surface without destroying the sampling device. Examine terminals for adults and immatures. Young leaves in terminals will become discolored and die under heavy infestations. Systemic insecticides control thrips and aphids. Early season control of thrips is extremely important in areas where tomato spotted wilt damage has occurred during the past season.
Three-cornered alfalfa hopper. You can often see these triangular bodied insects flying as you move through a field. Examine plants for damage by parting the foliage and closely checking stems for signs of girdling. Both nymphs and adults move around the stem when plants are checked. Nymphs have an appearance similar to adults, but they cannot fly.
Infestations of leafhoppers, three-cornered alfalfa hoppers or spider mites are reported as:
light -- only occasional pests or damage
medium -- pest or damage readily seen
heavy -- pest and/or damage generally observed throughout the field.
Treat small areas of fields for spider mites to prevent infestations from spreading. You should control three-cornered alfalfa hopper and/or leafhoppers when you detect medium infestations that appear to be spreading across a field.
Cutworms. To detect cutworms, observe the soil surface near the base of plants and check the top inch of soil where cutworms hide. Control with foliar sprays or granular application. Bait formulation provides effective control.
Foliage-feeding caterpillars (Corn earworms, loopers, armyworms, velvetbean caterpillars). Shake plants to dislodge caterpillars from foliage and count the number of larvae on the ground that represents 3 row-feet. You can do this by shaking one-half of 3-foot sections of two adjacent rows into the middle and counting caterpillars on the ground. Control when you find an average of four or more larvae per foot of row in a field.
1 Peanut Pest Management in the Southeast, CES Regional publication, Bulletin 850, University of Georgia.
Insect Insecticide* Amount Per
Acre Precautions
and
White Grubs Furadan 3.3-6.7
lb/acre (36-inch row spacing); 3.5-6.7oz/1000 linear feet of row Use
in furrow at planting. See label restrictions.
Wireworms (Same
controls, remarks, and precautions as White Grubs)
Whitefringed
Beetle Dyfonate 1
gal 4EC Apply
broadcast and incorporate into the soil to a depth of 3 inches.
Southern
Corn Rootworm Dyfonate 20
lb 10%G Apply in
12-18inch/band over row at early pegging or at first sign of an
infestation. Do not apply Dyfonate more than 30 days after pegging
begins. Do not harvest within 21 days after treatment with Lorsban
nor within 80 days after treatment with Furadan. Do not feed treated
peanut forage.
Lesser Cornstalk
Borer Dyfonate 20
lb 10%G (Same
remarks and precautions as Southern Corn Rootworm.)
Thrips Di-Syston 4-6
lb 15%G or Apply
granules in furrow with seed at planting time. If you use liquid,
apply 1-2 inches to the side of seed. Use lower rate on light sandy
soils. May cause burn on seedling leaves, but plants usually recover
without permanent damage. Remove and destroy plants with symptoms
of Tomato Spotted Wilt Virus. Keep weeds down in fields to reduce
movement of virus-bearing thrips from weed hosts. Fields could be
reinfested after treatment because of the movement of these insects
from wild host plants. Continue to observe fields after treatment
for these insects. Orthene .66-1
lb 75S Apply
in 10-50 gal water with ground equip. and 5-10 gal for aerial application.
Leafhoppers (Same
control, remarks, and precautions as Thrips)
Three
Cornered Alfalfa Hopper : (Same
control, remarks, and precautions as Thrips)
Spider
Mites Comite 2
pt 73% EC Use
a minimum of 20 gal/acre of spray solution with ground equipment
or 5 gallons with aerial equipment when using Omite or Comite.
Rednecked
Peanut Worm Asana .85-1.7
oz 1.9EC Do
not exceed .15 lb ai/acre per season. Apply controls as needed to
prevent excessive bud damage.
Corn
Earworms Asana .85-1.7
oz 1.9EC Do
not exceed .15 lb ai/acre per season. Apply to foliage as needed
to prevent excessive damage. Usually peanuts can tolerate up to
4 "worms" per foot of row without economic injury.
Velvetbean
Caterpillars (Same
control, remarks, and precautions as Corn Earworm)
Green
Cloverworm (Same
control, remarks, and precautions as CornEarworm)
Beet
Armyworm Lannate 1
½-3 pt 2.4 LV Good
coverage of the plants is essential in the control of these insects.
Fall Armyworm Lannate ¾-1
½ pt 2.4LV Good
coverage of the plants is essential in the control of these insects.
Looper Lannate 1
½-3 pt 2.4LV
Cutworms Dylox-Proxol 20
lb 3-5% bait When
using sprays for control, use a nozzle to produce a coarse spray.
*
Do not feed treated vines to livestock.
and Formulation
Remarks
Grubs are the larvae of May or June beetles. They have a thick,
white "C"-shaped body with a brown head and three pairs of legs.
They live in the soil and feed on underground plant parts. Grubs
are usually a problem when peanuts are planted following sod.
These hard, slender-bodied larvae vary in color from dark brown
to bright yellow. The adults are commonly known as click beetles.
Eggs are deposited and hatch in the soil, where the larvae feed
on underground plant parts before they mature pupated and emerge
as adults. Like grubs, wireworms are usually a problem following
sod.
The adult beetles are dark gray, about ½-inch long and have
a white fringe or band along the outer edges of the body. They feed
on outer margins of leaves. The larvae of grubs do the principal
damage by feeding on roots or other underground parts. The grubs
are yellowish-white, about ½-inch long. They generally require
11 months for development into adults, but under some conditions
may require up to two years or more. Whitefringed beetles normally
overwinter as eggs or larvae. They usually produce one generation
a year and spend all but about three months in the soil.
or 40 lb 10%G
The adult stage is the spotted cucumber beetle (greenish-yellow
with black spots) that lays eggs at the base of plants. The tiny
white larvae burrow in the roots, crowns, and stems, often causing
the necessity to replant.
Furadan
Lorsban
6.7-13.3 lb 15%G
10-13 lb 15%G
This caterpillar is small and slender with alternating green and
brown bands on its body. It lives in a silken tube just below the
soil surface and bores into and tunnels up the stem. Lesser cornstalk
borer frequently attacks seedlings emerging from the ground or shortly
thereafter. It is an erratic pest with outbreaks usually occuring
during dry periods. Damage can be reduced significantly by keeping
the land free of weeds and grass for several weeks before planting.
Lorsban
10-13 lb 15%G
These are tiny insects about 1/64 of an inch long. The adults are
dark and winged, and the nymphs are wingless and yellow. They feed
by rasping the young leaves of the bud and sucking out fluid. This
results in scarred, deformed, or "possum-eared" leaves. Tomato Spotted
Wilt Virus -- Thrips transmit this disease. Initial symptoms of
Tomato Spotted Wilt Virus appear as a thickening of veins on young
foliage within the leaves, curling inward and downward. Internodes
shorten, and immature fruit fails to ripen. Dark purple streaks
can occur on the leaves, stems, and fruits. Symptoms may also show
up as a blighting and blackening of young shoots. On individual
leaflets, small, dark, circular dead spots may appear and later
have a bronzed appearance. Badly spotted leaves may turn dark and
wither. The fruits are generally reduced in size, distorted, and
have irregular yellowish blotches.
(Contact Dr. Frank Killebrew,
plant pathologist, MSU-ES, for more information on Tomato Spotted
Wilt Virus.)
Furadan
Temik
Thimet
3/4-1/4 pt 6EC
3.3-6.7 lb 15%G
2-5 lb 15%G
4-6 lb 15%G
Leafhoppers are small, green or brownish wedge-shaped bugs often
called Sharpshooters. They have piercing-sucking mouthparts and
damage peanuts by sucking sap from leaves and buds, causing leaf
tips to turn brown (called "hopper burn").
The nymph is straw-colored. The adult is wedge shaped and green.
The TCAH over winters as an egg or adult in plant tissue. Plant
injury results from puncturing of stems when sucking sap and depositing
eggs. The punctures are arranged to create a girdle around the stem.
These tiny pests, about 1/100 of an inch long, are not insects but
closely related animals that damage peanuts by sucking fluid from
the undersides of leaves, causing them to turn yellow and die. They
are not a common problem but may appear from time to time.
Omite
3-5 lb 30W
Larvae are small, white to cream-colored with brown heads and a
reddish band just back of the head. Bud damage results from larval
feeding. Control does not usually result in a yield increase.
Pydrin
2 2/3-5 1/3 oz 2.4EC
Because this insect is a general feeder found on other crops such
as corn, cotton, soybeans, tobacco, and tomatoes, it can develop
large infestations. These caterpillars vary in color from light
green or pink to nearly black but are generally lighter on their
under surface. They have alternating light and dark stripes along
the length of their bodies. When disturbed, the insect will curl
its body up very tight. Small corn earworms are easier to control
than the larger ones, so it is important to check fields carefully.
Lannate
methomyl
(Lannate
Nudrin)
Orthene
Pydrin
Sevin
¾-1 pt 2.4LV
6-8 oz 90%SP
1-2 pt 1.8L
1-1 1/3 lb 75S
2 2/3-5 1/3 oz 2.4EC
1 ¼-1 7/8 lb 80S
These caterpillars attack foliage, strip plants of leaves, and destroy
the terminal buds. They are green and usually have dark stripes
running the length of the body. The caterpillars can reach 2 inches
in length and are very active when disturbed. The adult moths are
light brown and have a diagonal dark line across their wings from
the front wing tip inward toward the body.
The green cloverworm larva has a looping movement when crawling.
It is uniformly pale green with white stripes running along the
sides. It has three pairs of prolegs and its body is not tapered.
When disturbed, this insect becomes very active. The adult is a
dark brown moth.
The larva has a black spot on each side of the second body segment,
has four pairs of prolegs, and is about 1 1/4 inches long when full
grown. The worms curl up when knocked to the ground. Larvae vary
from grayish-green to near black with pale lines running the length
of their bodies.
methomyl
(Lannate
Nudrin)
6-8 oz 90% SP
2 pt 1.8L
The stripes and coloration of these caterpillars are highly variable;
however, they can generally be identified by a white inverted "Y"
mark on the front of the head. The adult moth lays eggs in a furry
cluster and when these hatch, the caterpillars move and feed together.
methomyl
(Lannate
Nudrin)
Pydrin
Orthene
6-8 oz 90% SP
2 pt 1.8L
5 1/3-10 2/3 oz 2.4EC
1-1 1/3 lb 75S
The larva (worm stage) displays a characteristic looping movement
when crawling. It is light green with thin white lines running the
length of the body on the sides and top. The body tapers toward
the head. The larva has two pairs of prolegs near the rear.
6-8 oz 90% SP
These caterpillars are stout and dark colored. During the day they
rest just below the soil surface, under trash, or in cracks. Most
damage is done at night when they climb plants and feed on foliage;
however, they will cut plants off at the soil surface.
Lannate
2-4 pt 1.8L
1 ½-3 pt 2.4LV
Mississippi State University
does not discriminate on the basis of race, color, religion, national
origin, sex, age, handicap/disability, or veteran's
status. By Dr. Jim
Hamer, former Extension Entomologist Copyright by Mississippi State University. All rights reserved.
Extension Service of Mississippi State University, cooperating with
U.S. Department of Agriculture.
Published in furtherance of Acts of Congress, May 8 and June 30,
1914. Ronald A. Brown,
Director
This document may be copied and distributed for nonprofit educational purposes provided that credit is given to the Mississippi State University Extension Service.
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