Crop Profile for Peanuts in Georgia

Prepared: December, 2003

• Georgia commonly ranks first in the United States in peanut acreage planted and acreage harvested. Planted acreage from 2000-2002 ranged from 494,000 acres (2000) to 515,000 (2001). Acreage harvested ranged from 492,000 acres (2000) to 515,000 (2001). More information concerning yield/acreage/price/etc. is available at these web sites.

  http://www.nass.usda.gov/ga/index.htm
  http://www.usda.gov/nass/

• Georgia is usually first in peanut production, with yields ranging from 1.3 billion lbs. (2000) to 1.7 billion lbs. (2001).
• Georgia production accounted for 40% of the U.S. crop in 2002.
• The average yield in 2002 was approximately 2,600 pounds per acre.
• The 2002 Georgia peanut crop was valued at $230 million; the 2000 crop was valued at $388 million.
• Under the new farm bill, growers within the peanut quota system will receive at least $355/ton for peanuts. Individual contracts may bring a grower more or less money per ton.
• Nearly all Georgia peanuts are marketed for processing.
• Cost of production is estimated at $594 per acre ($475/ton) for dryland peanuts and $740/acre ($423/ton) for irrigated peanuts. You can find more information about production costs/budgets for Georgia peanuts at these web sites.
  http://www.ces.uga.edu/Agriculture/agecon/interactive.htm
  http://www.ces.uga.edu/Agriculture/agecon/budgets/crops/crops.html

Commercial production of Georgia peanuts is concentrated in the southwestern part of the state, although peanuts are grown commercially across the southern half of Georgia.

Note: Georgia posts a tremendous amount of information about peanut production on the web. Analysts are strongly encouraged to visit http://commodities.caes.uga.edu/fieldcrops/Peanuts/homepage.shtml

• Sandy loam soils with good drainage are preferred soil types for peanut production. Soil pH should be in the range of 5.8 to 6.5 and the soils should be easily tilled with a moderately deep rooting zone for easy penetration by air, water, and roots.
• Crop rotation is the most important cultural practice utilized in peanut production. A long rotation (2 years) with either a grass-type crop or cotton has been effective in reducing nematode and soilborne disease problems and permits better control of weeds.
• Nearly all Georgia peanuts are planted in conventionally tilled fields.
• Georgia peanuts are grown dry-land and irrigated. Approximately 60% of the Georgia peanut acreage planted in 2000 was irrigated.
• Optimal planting dates are between April 23 and May 25. Normal planting begins late April and ends in mid June. Harvest begins early September and ends early November.
• Varietal selection, based on pest resistance (primarily disease), is also critical for cost effective production.

Growers typically apply an insecticide and an herbicide at planting. Nearly 90% of the soil insecticide is loaded into the spreader with a "lock and load" system that limits exposure to the mix/loader.

Nearly all applicators use ground equipment with enclosed cabs. Larger farms are more likely to have closed cabs.

During the season, a typical farm would make from 8-12 pesticide applications per year. A typical applicator could cover about 25 acres per hour. On smaller farms (less than 500 acres), a single individual may make all of the pesticide applications. A large peanut farm may have 2,500 acres, but the operation would be more likely to have several people that drive spray rigs.

When the peanuts reach the flowering stage, nearly all growers make one application of gypsum to provide calcium for the developing peanuts.

Many growers cultivate the row middles one time near the beginning of the season. Additional cultivation during the season is rare.

From 40-50% of the Georgia peanut acreage is irrigated each season using a center pivot system. Sporadically during the season, someone may have to visit the pivot to implement repairs or adjustments. It is not necessary for anyone to enter the field to move irrigation equipment.

About 20% of the Georgia peanut acreage is formally scouted. Peanuts are scouted once per week. It takes a typical scout about 2 hours to scout 100 acres of peanuts. Nearly all professional scouts are scouting other crops (e.g., cotton) in addition to peanuts. These scouts spend a majority of the day scouting fields or traveling to the next location.

Nearly all peanuts are monitored informally. The grower or an employee will spend 1-2 hours per week driving near the fields or walking in the field margins.

About 20% of the Georgia peanut farms monitor weather instruments to determine when irrigation should be applied or to determine the risk of disease. The grower or a farm employee may spend up to 3 hours/week visiting weather instruments in or near each field. The monitoring equipment may in the field or at the field margin.

In 2001, insect losses (yield reduction + cost of control) in Georgia peanuts were about $12.8 million. Thrips were responsible for about $5.8 million in losses, followed by lesser cornstalk borer ($2.1 million), wireworms ($1.8 million), 3-cornered alfalfa hopper ($1.3 million), and spider mites ($1.2 million). For more detail, review IPM publications at www.ent.uga.edu.

Thrips are tiny, slender insects that jump or fly when disturbed. There are several species that feed on peanuts and they range in color from yellow to black. They feed in the buds of plants on the young folded leaflets, causing scarred, deformed leaves often referred to as "possum-eared." Tobacco thrips and the less common western flower thrips are also vectors of the tomato spotted wilt virus (TSWV), a very serious disease in Georgia peanuts. From 85-90% of the Georgia peanut acreage is treated with insecticide at planting to control thrips.

Foliar pests feed on the above-ground plant parts. In addition to thrips, a complex of lepidopteran larvae consume the leaves. Several types of leafhoppers and spider mites can cause losses in peanuts. Considerable foliage can be lost without reducing peanut yields. If a good growth of foliage is present, four or more foliage-feeding caterpillars per foot of row are required to cause a yield reduction. When mixed populations of foliage feeders are present, growers use an insecticide recommended for the insect or insects that make up a majority of the population.

• Fall armyworms are multi-colored, striped larvae, usually having a white inverted "Y" on their heads. They feed by eating plant foliage. Their life cycle requires approximately 30 days, with about half of this time spent in the larval stage. There may be several generations of the fall armyworm in one year.

• Corn earworms vary in color from light green to almost black. They are probably the most common of all the caterpillars that feed on peanut foliage and may also feed on blooms. Their life cycle requires about 30 days; 14 to 21 days of this are in the larval stage.

• Cutworms are fat, tan to dark-colored caterpillars. They hide under trash, in cracks, or just below the soil surface during the day. Their primary damage is caused when they climb the plants and feed on the foliage. They can quickly and unexpectedly defoliate peanuts. Foliage feeding usually occurs at night, and the "worms" return to the soil during the day.

• Velvetbean caterpillars are green to black larvae that usually have white stripes the length of the body. These larvae are very active when disturbed. They feed on the foliage, and may completely strip plants of all leaves and destroy the terminal buds. Several generations may occur each year.

• Loopers are often found feeding on peanut foliage. Their eggs are laid singly on the foliage of the plants. Larvae pass through six instars in a period of two weeks or slightly longer and pupae are attached to the plant by a web. The complete lifecycle requires 30 to 35 days.

• Spider mites are very tiny insect-related pests that feed by sucking juices from the undersides of the leaves, causing them to turn yellow and die. Mites are not a common problem, but may cause complete defoliation in some fields. Spider mites are a serious problem in peanuts about one season out of every five years.

• The 3-cornered alfalfa hopper and other leafhoppers are small green hopping insects sometimes referred to as "sharpshooters." They feed by sucking plant juices. This causes peanut leaves to turn yellow, especially on the tips.

Soil pests attack the peanut seedlings, and they attack the pegs and pods that become peanuts. About 25% of the Georgia peanut acreage is treated with a soil insecticide to manage these pests.

• Lesser cornstalk borers are dark blue-green larvae ranging from 1/2 to 3/4 inch in length with brown bands around their bodies. They feed on pegs and pods, bore into the plant near the soil line, and tunnel throughout roots and stems. They live in silken tubes beneath the soil surface. Damage to peanuts is usually more severe in dry weather.

• White grubs are larvae of the May or June beetles. There are about 200 known species of grubs. They live in the soil and feed on the underground parts of the peanut plant. These insects are most often a problem where row crops follow sod.

• Whitefringed beetle larvae are white, legless grubs that are up to 1/2 inch long. Larvae feeding on the underground parts of the plants cause most economic damage. Stands can be drastically reduced.

• Wireworms are slender-bodied larvae that vary from dark brown to yellowish in color. The adults are commonly known as click beetles. The larval stage lasts from one to two years, and they usually cause problems for two years following sod.

• Southern corn rootworms damage peanuts by feeding on pegs and pods in the soil. Infestation by rootworms is more common in heavy, poorly drained soils, but may occur in sandy soils. Damage will vary from a slight decrease in grade to complete destruction of the crop.

Insecticides. According to USDA data about 80% of peanut acreage was treated with insecticide in 1999. http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/#field

• Aldicarb (0.6-1.05 lb a.i./acre). Growers typically treat about 40% of the peanut acreage with one application of aldicarb at planting, primarily to control thrips.

• Phorate (1.0 lb a.i./acre). Growers treat about 40% of the peanut acreage with one application of phorate at planting. Phorate will help control thrips and soil insects. Additionally, phorate provides some protection against tomato spotted wilt virus.

• Acephate (0.19 lb a.i./acre). About 10% of the acreage is treated with an application of acephate at planting to control thrips.

• Chlorpyrifos (2.0 lb a.i./acre). About 25% of the acreage is treated at pegging with one application of chlorpyrifos to control peg/pod injury from soil pests. Chlorpyrifos also provides some suppression of the peanut disease white mold.

• Esfenvalerate (0.015-0.025 lb a.i./acre), cyhalothrin (0.015-0.025 lb a.i./acre), and methomyl (0.34-0.45 lb a.i./acre). Growers typically make 1-4 applications from this group of chemicals to control foliar pests. The grower will select a chemical based on the complex of pests present.

Review additional insecticide recommendations in the Georgia Pest Management Handbook.

Nonchemical alternatives and IPM

Nearly all Georgia peanut fields are infested with weeds. Weeds are generally categorized as grasses, broadleaves, and nutsedges. Effective weed management is essential to produce commercial peanuts. A comprehensive discussion and slideshow about weed control in Georgia peanuts can be found at this web site. http://www.cropsoil.uga.edu/weedsci/slides/peanut2000/

The ten most troublesome weeds in Georgia peanuts are:

• Florida beggarweed
• Nutsedges
• Tropic croton
• Sicklepod
• Texas panicum
• Bristley starburr
• Morningglories
• Wild Poinsettia
• Citronmelon
• Pigweeds

The USDA reported that 99% of the Georgia peanut acreage was treated with herbicide in 1999.

http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/#field

Herbicides

• Paraquat (0.63-0.94 lb a.i./acre). Many growers make one application of paraquat well before planting to kill emergent weeds. This practice is especially common when peanuts are being produced with minimal tillage. The USDA reported that 57% of the Georgia crop was treated with paraquat in 1999.
• 2,4 D (0.24-0.48 lb a.i./acre). Many growers combine 2,4 D with paraquat for the pre-plant treatment. The USDA reported that 48% of Georgia peanut crop was treated with paraquat in 1999.
• Ethalfluralin (0.75 lb a.i/acre) or pendimethalin (0.75-1.0 lb a.i./acre). Nearly all growers make one application of one of these two herbicides as a pre-plant incorporation. The USDA reports indicate that pendimethalin (47% of crop treated) and ethalfluralin (46%) were commonly used in 1999.
• Bentazon (0.75-1.0 lb a.i./acre). Growers commonly make an application of bentazon during the season. The USDA reported that about 46% of the Georgia acreage was sprayed with bentazon during 1999.
• Acifluorfen (0.125-0.138 lb a.i./acre). Growers commonly use aciflourfen during the season. The USDA indicated that 25% of the acreage was treated with aciflourfen in 1999.
• Metolachlor (2.0-2.5 lb a.i./acre). Growers commonly apply metolachlor during the season. The USDA reported that about 20% of Georgia acreage was treated with metolachlor in 1999.

The University of Georgia recommends a wide variety of herbicides to manage weeds in peanuts, and new herbicides are regularly registered for this market. An individual grower will choose herbicides based on the pressure and composition of the weed population. Review pesticides recommended for weed management in the Georgia Pest Management Handbook.
http://www.ent.uga.edu/pmh

Nonchemical alternatives and IPM

Growers incorporate other techniques in an IPM program for weeds, but nonchemical methods cannot replace the critical role of herbicides in peanut production. Growers can only cultivate peanuts early in the season. Hand weeding is not common, but it may be used in small areas where herbicides failed to control weeds.

No effective biological controls are available for peanuts, although birds, soil-borne fungi, and insects may help to reduce the bank of weed seeds.

Growers cultivate, rotate crops, and manipulate both row spacing and planting dates to reduce weed competition in peanuts.

Cultivation is the most widely used and effective cultural control for weeds. However, cultivation can also exacerbate problems with soil-borne diseases.

Concerns about peanut diseases are generally the force driving rotation with other crops, but rotation also benefits weed management. Peanut production promotes populations of weeds (e.g., legumes) that are taxonomically similar to peanuts and perennial weeds such as nutsedges. Rotating peanuts with a grassy crop, like corn or pasture, can provide marked reductions in both disease and weed pressure.

Peanuts have traditionally been planted in single rows 36 inches apart. Many growers are replacing this row spacing with twin rows 5-7 inches apart. The canopy between these twin rows closes more quickly, and weeds are reduced. Peanut yields have been increased with the twin row spacing, but there has been no significant reduction in the need for herbicides.

The plating period for Georgia peanuts is limited because the growing season is relatively long, but growers must delay spring planting until the soil is warm enough. Most growers prefer to plant as early as possible within the planting window to let the peanuts gain an advantage over later-emerging weeds. Additionally, a peanut variety that matures quickly may avoid late-season weed problems.

The two nutsedge species, yellow and purple nutsedge, are herbaceous perennials that regrow from soil borne tubers. Tubers germinate sporadically, and dormant tubers cannot be killed with herbicide application. Additionally, nutsedge foliage is very waxy and grows upright. Herbicides do not stick well to the nutsedge foliage, and absorption by the plant is very low.

Grass control is critical for peanut production. In addition to competition for water and nutrients, uncontrolled grasses bind the peanut pods in a sod mat of roots, which greatly interferes with harvesting. Texas panicum is the most important grassy weed in Georgia peanuts. Other grasses have smaller seeds, and herbicides are more effective in preventing germination. Texas panicum has a relatively large seed, which can germinate below the herbicide application zone.

Broadleaf weeds compete with peanuts for light, water, and nutrients. Additionally, taller weed species interfere with the effective application of fungicides. Therefore, controlling weeds is essential for good control of diseases. Eight of the ten most troublesome weeds in Georgia peanuts are broadleaf weeds.

According to Georgia Plant Disease Loss Estimates, leaf spots and white mold were the most expensive diseases in 1998 with loss + cost of control exceeding $50 million for each of these diseases. Nematodes ($24.4 million in loss + cost of control), tomato spotted wilt ($18.4 million), and cylindorcladium black rot ($13.3 million) completed the top five most costly peanut diseases in 1998. For details, refer to UGA Extension Bulletin Pat 99-002 available at www.ces.uga.edu

White Mold (fungus Sclerotium rolfsii)

White mold (also called southern stem rot) results in a brown dry rot of the lower stem and crown and one or more branches wilt and die. Up to 10 to 12 adjacent plants may wilt and show signs of the disease. The stems of diseased plants (and often the ground and lower leaves) are covered with a dense, white fungus growth. Small, brown fungus fruiting bodies similar to mustard seed usually form on dead stems and leaves.

Peanut Leaf Spots (fungi, early leaf spot, Cercospora arachidicola; late leaf spot, Cercosporidiuum personatum)

The first symptoms of both diseases are small, pale yellow or blanched spots. These soon enlarge and become tan to black. The color of the spot on the lower leaf surface can often be used to distinguish between early and late leaf spots. Early leaf spot is brown and late leaf spot is black.

Nematodes (root-knot Meloidogvne arenaria, M. hapla)

Above-ground symptoms are yellowing, wilting, and stunting of plants in areas from a few feet in diameter to several acres. Roots usually have knots and galls that vary in size from slight swelling to large galls 3 or 4 times the size of the root. Pegs and pods are usually distorted with galls.

Nematode injury is often difficult to diagnose. Damage to plants can easily be mistaken for the symptoms of a nutritional deficiency, a soil-related disorder, drought stress, and soil-borne diseases, such as southern stem rot or CBR. Often, the foliage looks normal while the roots and pods are badly galled. Symptoms of nematode injury never occur uniformly across a peanut field.

Tomato spotted wilt virus (TSWV) has emerged as a critical disease of Georgia peanuts. TSWV is transmitted to peanuts primarily by the tobacco and western flower thrips. The virus is acquired by the larvae feeding on diseased weeds or peanuts and is transmitted by the adults. Viruliferous adults overwinter in the soil or survive on TSWV-infected weeds that grow during the winter months. This virus is not seed transmitted.

Many production decisions are affected by the risk of tomato spotted wilt virus, including varietal selection, planting date, pest control, and row spacing. The Georgia peanut team has developed a series of recommendations and risk factors that are used by peanut growers wherever this disease if found. Analysts are advised to visit this web devoted to TSWV. http://www.ces.uga.edu/pubcd/b1165-w.html

The soil fungus Cylindrocladium crotalariae causes Cylindrocladium black rot. Losses from black rot are most likely in areas where Virginia-type peanuts have been grown.

High soil moisture levels favor black rot, particularly in the late spring and early summer. Black rot symptoms are often confused with symptoms of white mold, root-knot nematode, and tomato spotted wilt virus.

Limb rot, caused by Rhizoctonia solani, is chiefly a disease of irrigated peanuts, although losses may also occur in dry-land peanuts. Excessive water, fertilizer, and tractor traffic will exacerbate disease severity and pod loss. Limb rot is most frequently seen during periods of hot, wet weather in late summer or early fall.

Several soil-inhabiting fungi such as Aspergillus niger, Rhizoctonia solani, and Pythium spp. can cause seed to rot or seedlings to die quickly (damping off). These conditions are greatly exacerbated when unfavorable soil conditions (cool, wet) retard germination and seedling development. Soil that is excessively dry favors development of A. niger. Poor quality seed and replanting a field to peanuts following peanuts will also increase the risk of seed/seedling disease.

Fungicides. Data from USDA indicate that 85% of Georgia peanut acreage was treated with chlorothalonil in 1999, followed by tebuconazole (47%), sulfur (15%), propaconazole (14%), azoxystrobin (10%), and copper hydroxide (3%). http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/#field

Regular fungicide applications are critical for peanut production. Growers typically apply fungicides during the season on a 10-14 day schedule for a total of 7-10 fungicide applications per year. The schedule and number of applications are determined by weather conditions and disease pressure. Growers use several different products to manage disease resistance.

• Chlorothalonil: very important for management of diseases and for preventing/delaying disease resistance to other products. Nearly all growers use chlorothalonil in their fungicide rotation. The USDA-NASS reports that 85% of the Georgia peanut acreage was treated with chlorothalonil in 1999. A grower would typically use chlorothalonil from 2-4 times per season as part of the overall fungicide rotation.

• Pyraclostrobin or azoxystrobin: applied 1-2 times to about 40% of the acreage. Most growers use azoxystrobin now, but the market is expected to shift to pyraclostrobin because it is considered to be more effective.

• Tebuconazole. Growers commonly used tebuconazole in the fungicide rotation.

• Propiconazole + trifloxystrobin). This new product is expected to capture a substantial part of the market now shared by tebuconazole and the other – strobin products.

A typical fungicide rotation would be 1-2 applications of chlorothalonil, followed by 1-2 applications of pyraclostrobin or azoxystrobin fungicide, followed by 1-2 applications of chlorothalonil, followed by 1-2 applications of tebuconazole.

Most growers are conscious of the potential for disease resistance to fungicides, so they are careful to rotate among fungicides in different chemical families. For example, a grower would avoid rotations with azoxystrobin, pyraclostrobin, and propiconazole + trifloxystrobin. Likewise, propiconazole + trifloxystrobin would not be rotated with tebuconazole.

Review pesticides recommended for disease management in the Georgia Pest Management Handbook

Nonchemical alternatives and IPM. Disease management in peanuts is based on a combination of tactics. Effective fungicides are a critical component. Chlorothalonil is particularly important because of its role in resistance management. Other products, with a more targeted mode of action, are much more susceptible to resistance problems. The availability of chlorothalonil will prolong the effective life of many other fungicides.

Growers use a variety of cultural practices to reduce disease losses. Some type of crop rotation program is used on nearly all peanuts. Deep tillage and resistant cultivars are common tools in peanut production. Every peanut farmer works to provide optimal water and fertilizers. Finally, growers typically plant peanut seed that has been treated with fungicide and/or insecticide. In 2003, Extension specialists recommended seed treated with Vitavax PC, Granox PFM, Pro-Ixed System II or III, or Gustafson 4-Way.

For complete details about peanut production in Georgia, visit the UGA Peanut Website at http://commodities.caes.uga.edu/fieldcrops/Peanuts/homepage.shtml.

This web page carries all of the information about the UGA peanut program, including the UGA peanut team and links to a wide variety of peanut publications about production.

John A. Baldwin, jbaldwin@uga.edu. UGA Peanut Agronomist.

John P. Beasley, jbeasley@uga.edu. UGA Extension Agronomist.

Tim Brenneman, arachis@tifton.uga.edu. UGA Plant Pathology.

Steve L. Brown, bugbrown@uga.edu. UGA Entomology.

Albert Culbreath, leafspot@tifton.uga.edu. UGA Plant Pathology.

Eric Prostko, eprostko@uga.edu. UGA Weed Scientist.

The Georgia Pest Management Handbook. [Paul Guillebeau, Ed.] Published annually. Special Bulletin 28.

Profile prepared by Paul Guillebeau, IPM/Pesticide Coordinator, Department of Entomology, University of Georgia, Athens GA 30602 pguillebeau@bugs.ent.uga.edu