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Based on 1980 estimates, North Carolina forages and pastures comprise a total of over 900,000 hectares (about 2,222,000 acres). This acreage includes not only improved and unimproved pasture but also legume and grass hay crops. Since many different kinds of plants fall into the category of forages, it is not surprising that the insect pests attacking these crops are just as numerous and varied. Several hundred species are associated with alfalfa alone. Fortunately, only a few of these are economically important. The alfalfa weevil remains the primary pest problem of alfalfa, while white grubs are the corresponding threat to grass forages. Although the number of serious pests is few, their chemical control poses the problem of insecticide residues.

Key to Pests of Forages and Pasture

1. Caterpillars - All moth larvae described in this section have three pairs of legs near the head and five pairs of prolegs.
   
   1. Armyworms - Usually 30 to 40 mm long when fully grown, these smooth-skinned caterpillars are voracious foliage feeders.
      1. Armyworm (true) - The larva is basically yellowish- or greenish-brown with three dark, longitudinal stripes and is 30 to 35 mm long when fully grown. The head capsule has markings like those of the fall armyworm, but they are lighter or less intense (Fig. A). Feeding primarily at night, the armyworm often does much damage to the tender, succulent foliage of seedling grasses. During the day, this caterpillar usually hides among debris on the soil surface.

      2. Fall armyworm - The green, brown, or black larva may be as long as 40 mm and has a dark head capsule usually marked with a pale, but distinct, inverted "Y" (Fig. B). It has a black, longitudinal stripe down each side of its body and a yellowish-gray stripe down its back. As its name implies, damage is most prevalent in lush grass crops during late summer and fall.

   2. Cutworms - These fat worms may be as long as 45 mm and curl up when disturbed. Depending upon their stage of development, cutworms may sever seedlings at the soil line or feed on foliage.
      1. Black cutworm - This caterpillar varies from gray to black in color, often appearing greasy. The skin of this cutworm is granulated (as seen under a 10X hand lens), the granules resembling rounded, flattened pebbles (Fig. A). It burrows in soil and debris during the day and, when mature, cuts or partially severs seedlings near the soil line at night. When immature, the larva feeds primarily on foliage.
         

      2. Granulate cutworm - This caterpillar has a pale brown head, a dark brown band dow 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. B).

      3. Variegated cutworm - This climbing cutworm feeds on foliage, buds, and fruit. Its smooth-skinned body is pale gray to dark brown with a row of yellow or orange spots down the middle of the back. A black spot and a yellow spot occur on the eighth abdominal segment.

   3. Sod webworms - Several kinds of sod webworm caterpillars consume leaves and tender new growth. Basically greenish with black spots, they are 16 to 19 mm long when mature. Silky webbing near the soil line is often found in association with these foliage-feeding caterpillars.

2. Grasshoppers - Full grown grasshoppers are 19 to 33 mm long. They consume foliage as well as sever stalks.
   

3. Weevils - A few species of small, dark, snout beetles (Fig. A to B) feed on the foliage of legume forage and pasture crops.
   
   1. Alfalfa weevil - The dark brown, gray-mottled weevil, less than 6 mm long, has a darker stripe down its back more than half the length of the body. Its snout is at least twice as long as it is wide (Fig. A). This pest shreds leaves and destroys growing alfalfa terminals.

   2. Clover root curculio - This dark-colored weevil, 3 to 5 mm long, has a short, stocky snout about as long as it is wide (Fig. B). The curculio makes small, crescent-shaped notches in the leaves of alfalfa and clover. Small plants may be defoliated as soon as they emerge from the ground.

4. Weevil larvae - These soft-bodied, legless larvae feed on leaves.
   
   1. Alfalfa weevil larva - This slender, black-headed larva is green with white, longitudinal stripes. Less than 10 mm long, it shreds leaves and destroys growing terminals of alfalfa.

   2. Clover leaf weevil larva - Reaching a mature length of 12 to 13 mm, this stocky, greenish or yellowish larva has a white or pink line down the center of its back and a dark line along each side. Leaves of infested plants become full of small holes and irregular patches.

1. Aphids - These small, pear-shaped, winged or wingless insects (Fig. A) congregate primarily on the underside of leaves. They extract sap, causing the foliage to turn yellow, and then excrete a sweet, sticky, substance known as "honeydew." Black sooty mold grows on the surface of this excretion.
   1. Cowpea aphid - the adult of this species is black with white appendages and grows to 2 mm long. The nymph is pale gray with a powdery coating.

   2. Pea aphid - This pale green aphid may be as long as 4 mm and has long, slender cornicles.

2. Meadow spittlebug - Both the gray, brown, or spotted, 6-mm-long adult (Fig. B) and the orange, yellow, or pale green nymph extract plant sap. Hosts do not turn yellow, but may wilt, become stunted, develop a terminal rosette, and produce a lower yield. Nymphs are surrounded by white, frothy masses resembling spittle.

3. Potato leafhopper - This 3-mm-long insect (Fig. C) is yellowish to pale green with yellow to dark green spots, which can be observed under magnification. It pierces and extracts sap from leaf veins, causing yellowing of leaves, loss of vigor, or death of the plant.

4. Threecornered alfalfa hopper - The straw-colored nymph (about 4.6 mm long) and the green adult (6.0 to 6.5 mm long) are both wedge-shaped, the front of the body being widest (Fig. D). Their feeding and egg-laying activities on the lower stem may cause stem breakage and lodging.

5. Twospotted spider mite - This almost microscopic, eight-legged (larva six-legged) pest (Fig. E) feeds on the underside of leaves, often "spinning" a network of silken webs on which to travel and deposit eggs. Damage is indicated by a white cast to the leaves when viewed from a distance. This mite is identified by the adult female which is yellowish- to dark green with two or four dark, dorsal spots.

1. Clover root curculio grub - Roots are scored and girdled near the crown by a fleshy, legless, grayish-white grub measuring about 5 mm long when fully grown (Fig. A).

2. White grubs - These C-shaped, six-legged grubs (Fig. B) are 5 to 48 mm long. They eat or sever roots, thereby causing reduced plant growth or death, especially during drought. Small localized areas of unhealthy plants are often indicative of a white grub infestation. Fluffy soil may also accompany severely damaged spots.

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