Insecticide For Peas

Crop protection is a big deal. The development of pest-resistant crops, along with the invention of chemical pesticides and insecticides , has had a huge effect on modern agriculture. In fact, it’s estimated that pesticides and herbicides have increased annual corn yields in the U.S. by 30 percent, soybean yields by 27 percent, and wheat by about 50 percent .

Insecticide For Peas

Major Seedling Feeders

Aphids: Aphids (Aphis species and Macrosiphum euphorbiae) are soft-bodied “plant lice,” about 1/16 to 1/8 inch in length and are usually green, although some species are yellow, pink, brown, or black. They are most prevalent during cool, dry weather on small plants. Heavy populations of aphids can stunt plants by withdrawing large volumes of plant juices and delaying maturity

Treatments for aphid control should begin at any time colonies are found. In the home garden, spray foliage with soapy water, then rinse with clear water. Alternatively, use an insecticidal soap spray. Planting in aluminum foil that has been laid on the planting bed, as well as filling yellow pans with water to trap the aphids are also effective control measures. Once the weather warms up, natural enemies usually control aphids.

Thrips: Thrips (Frankliniella species) are small, slender, agile insects, rarely as long as 1/8 inch. They are commonly found in flowers of peas and beans but will also feed on leaves. Their presence in flowers at early bloom may result in poor fruit set due to pollination interference by thrips feeding.

Field observations indicate that three thrips per flower may interfere with pollination and cause defectively shaped pods. After pods are 1- to 2-inches long, the damage is primarily cosmetic since small blisters are generally the only result of their feeding.

In the home garden, planting in aluminum foil that has been laid on the bed tends to repel thrips. Insecticidal soaps may give adequate control.

Lesser Cornstalk Borer: The lesser cornstalk borer (Elasmopalpus lignosellus) is the larval (immature) stage of a small (½-inch long) brownish-yellow moth. Moths leave field corn when it begins to dry and enter late-planted fields of peas and beans. The moths lay eggs around the base of emerging plants. These eggs quickly hatch into larvae, which are small, slender caterpillars with green, blue, or brown bands around each body segment. The larvae bore into the stalks of young plants near the soil line and tunnel up and down the stalks. A silken tube is usually attached to the entrance hole where the larvae bore into the stem, and the larva may sometimes be found in this tube. Plants damaged by lessers become stunted, wither, and later die. Late plantings (those made after July 1) on sandy soil during hot, dry conditions often result in 30 to 50 percent stand loss.

Major Foliage/Stem Feeders

Several kinds of beetles and caterpillars may be found feeding on the foliage of peas and beans. The combined feeding of all or heavy populations of one species may require insecticide treatments. Peas and beans are fast-growing plants with heavy canopy due to an overabundance of leaves. Research has shown that 30 percent leaf loss prior to the bloom stage will not result in reduced yield or quality. In addition, these plants can tolerate up to 15 percent leaf loss during bloom and pod-fill stages without significant drops in yield or quality.

The following pests are considered major foliage feeders, and their combined feeding may require treatments to prevent yield and quality loss.

Mexican Bean Beetle: The Mexican bean beetle (Epilachna varivestis) is ¼- to 1/3- inch long, very convex, and yellow to coppery-brown. Each wing cover has eight small, black spots that form three rows across the body. Some of the beetles appear at the emergence of the earliest plantings, whereas others may wait until nearly two months later to leave their overwintering quarters.

After feeding on beans a week or two, the adult female deposits yellow eggs in groups of 20 to 50 on the undersides of leaves. The eggs hatch in one to two weeks, depending on temperature, and the larvae (immature forms) feed for two to four weeks. Both larvae and adults feed on the undersides of leaves, leaving the upper surface more or less intact. The larvae consume areas of leaf tissue, leaving veins between the chewed areas, which gives the leaf a skeletonized, lacy appearance. When abundant, larvae and adults will also feed on stems and pods. When full-grown, larvae are 1/3-inch long, yellow, and armed with black-tipped spines. Larvae change to pupae (the nonfeeding stage where the larvae change to adults) on plants — usually on the undersides of undamaged leaves. The pupal stage is cemented to leaves, and the adult emerges in about 10 days. From egg to adult requires about one month, and there are usually three generations per year. During some years, there may be a partial fourth generation.

Since most damage occurs during July and August, quick-maturing varieties of green beans planted very early or during late summer may escape damage. The snap bean varieties: ‘Wade’ and ‘Black Valentine’ are resistant or tolerant to Mexican bean beetles. In the home garden, handpick and destroy beetles and egg masses. Destroy crop refuse after harvest by working it into the soil or adding it to a compost pile.

Bean Leaf Beetle: The bean leaf beetle (Cerotoma trifurcata) is rarely a serious problem on beans or peas grown in South Carolina. The adults are about 1/5- to ¼- inch long. They vary considerably in color and markings but are typically red to yellow, with three or four black spots in a row along the inner edge of each wing cover. Damage caused by bean leaf beetles is twofold: (1) girdling of stems near the soil line and (2) large irregular holes chewed in leaves. Damage to beans and peas early in the season may result in stand reduction.

Spider Mites: Two-spotted spider mites (Tetranychus urticae) are minute, eight-legged pests that are more closely related to spiders than to insects. Adults and immature stages appear as tiny specks on the undersides of leaves where they pierce the leaf surface and suck sap. Lightly infested leaves develop tiny whitish speckled spots, while heavily infested leaves turn pale yellow or bronze-colored and dry up. The undersurfaces of leaves usually are covered with silken webs over which the mites crawl. Spider mites develop rapidly during hot, dry weather, and one generation can be completed in as few as eight days.

Insecticidal soaps generally offer adequate control when applied before the numbers are too high. Additionally, many mites can be removed with a strong spray of water. Natural enemies such as lady bugs are important natural controls.

Lima Bean Vine Borer: The lima bean vine borer (Monoptilota pergratialis) is an occasional pest of the large-stemmed bean varieties. The mature larva (caterpillar) is 7/8-inch long, bluish-green with a tint of pink on its back, and has a yellowish-brown plate behind its dark head capsule. It burrows into stems, typically just above or below nodes (that part of the stem from which a leaf grows), and hollows out cavities. Infested stems form galls (a tumor-like swelling), which eventually turn brown and develop a woody texture. Infested plants are weakened and have lower yields.

Cabbage Looper: The cabbage looper (Trichoplusia ni) is another defoliator of peas and, to a lesser extent, beans. This larva (caterpillar) is green with a thin white line along each side of the body and two others near the middle of the back. Damage caused by loopers is ragged foliage. They rarely reach treatment status on peas and beans in the absence of other foliage feeders. The heaviest populations usually occur on late-planted crops.

Major Pod Feeders

Cowpea Curculio: The cowpea curculio (Chalcodermus aeneus) is the most destructive insect pest of southern peas grown in South Carolina. Cowpea curculios are rarely a problem on snap beans. Small, brown, wart-like or blister-like spots are found on pods damaged by curculios. These are caused when the adult punctures the pod to feed or lay eggs. Damaged peas have small, dark, indented spots and often contain grubs.

The cowpea curculio overwinters (survives the winter) as an adult in crop refuse or grass in the field or on the border of the field. Tufts of broom sedge, particularly at edges of woods, are favorite hiding places for overwintering adults. The adult is an oval, hump-backed, bronze-tinged, black “snout” beetle that has small dents on the wing covers and on the upper side of the body. It is about ¼-inch long. Adults begin to leave their winter quarters in March or early April. This emergence continues until June or July or about the time that the first peas are available for egg laying. These overwintering adults are long-lived and may survive through August.

Eggs are laid as soon as peas are formed in the pods. The weevil (also called the “snout” beetle) punctures the pod and chews a small hole in the surface of the pea. A single egg is laid in each hole. A legless, pale yellow, brown-headed grub hatches from this egg.

The grub feeds on one or more peas before it reaches its full size of slightly more than ¼ inch long. It then chews an exit hole through the pod and drops to the ground. It enters the soil to a depth of about 1 inch and transforms into a pupa (a nonfeeding stage where the larva changes into an adult).

Approximately seven or eight days elapse from the time that the eggs are laid until the grubs emerge from the pod. The larvae pupate (transform to pupae) about six days after they leave the pod. About 21 to 50 days are required to complete the life cycle. There are two generations each year. Because eggs are laid over an extended period of time, generations overlap, and all stages can be present on southern peas at the same time.

Late southern peas isolated from early peas are usually not as severely damaged as early peas. Wild host plants produce pods that attract many curculios, and these can be a source of infestation.

The only feasible approach to the control of curculios is a preventive spray program. The current spray schedule recommended begins with a spray at first bloom and repeat treatments made on a five- to seven- day schedule.

Corn Earworm: The corn earworm (Helicoverpa zea) is primarily a problem on late-planted peas and beans, but early plantings may also be attacked. These worms vary greatly in color from a light green or pink to brown or nearly black and are lighter on the underparts. They are marked with alternating light and dark stripes running lengthwise on the body. The head is yellow and unspotted, and the legs are dark or nearly black. The corn earworm chews holes in both foliage and pods but prefers the latter. Levels requiring insecticide treatment are 5 percent damaged pods or one larva per 3 feet of row.

Tarnished Plant Bug: The tarnished plant bug (Lygus lineolaris) is a pest of snap and lima beans but rarely reaches pest status on southern peas. The bean growth period during which plant bugs are most important is full-bloom. The bugs withdraw plant sap and inject toxic saliva into the plant. The toxins may halt the development of blooms and young pods and cause dark spots to develop on older pods that are attacked.

The adult bugs are about ¼-inch long by less than half as broad, flattened, and oval in outline. They are a general brown color mottled with small, irregular patches of white, yellow, reddish-brown, or black. Nymphs (immature forms) are similar in shape to adults, with four black spots on the back. By late summer, adults and nymphs are numerous, but because of their color and shy hiding habits are not easily noticed. Late-planted beans are highly susceptible to attack and should be checked closely during the bloom stage. Treatments for bugs should be made when there is an average of one bug per 6 feet of row.

Stink Bugs: The southern green stink bug (Nezara viridula) is a serious pest of lima beans and snap beans during late summer and fall. These bugs are shield-shaped, bright green, bad-smelling, flattened, and about 5/8-inch long. The young (nymphs) are similar in shape and have black markings. Stink bugs damage beans in both the nymph and adult stages by sucking juices and injecting toxins. Although they may feed on leaves, pods are preferred. External signs of stink bug feeding on pods of snap bean show up as clear or water-soaked areas. On lima beans, the external damage on pods is not as clear. Inside the pod, developing beans become brown after bugs inject toxins and introduce yeast infections.

On snap beans, insecticide treatment is necessary during the bloom stage when there is an average of one bug per 10 feet of row. Lima beans are more sensitive to damage, and insecticide treatment is needed in the bloom stage when there is an average of one bug per 15 feet of row.

Control of Bean & Southern Pea Insects

Consult the discussion under each pest listed on this fact sheet for the “economic threshold” or the level of pest populations or plant injury necessary to warrant control measures.

The first choice for control of insect pests on vegetables always should be the lesser toxic pesticides. These will be less harmful to beneficial insects and have a much shorter pre-harvest interval or waiting period between spraying the crop and harvesting the vegetables. More than one application of an insecticide is typically required to control a pest. Always follow all label directions and observe waiting periods until harvest (pre-harvest interval).

Table 1. Natural, Less Toxic Pesticides and Contact Pesticides to Control Bean Pests.

Pests	Natural, Less Toxic Pesticides	Contact Pesticides
Aphids	Insecticidal soap Neem oil extract Pyrethrin	Bifenthrin Cyhalothrin Cypermethrin Malathion
Bean Leaf Beetle	Pyrethrin Neem oil extract Insecticidal soap Spinosad	Bifenthrin Cyhalothrin Cypermethrin
Thrips	Insecticidal soap Spinosad	Bifenthrin Cyhalothrin Cypermethrin
Corn Earworm  Bean Looper	Bacillus thuringiensis (B.t.) Pyrethrin Neem oil extract Spinosad	Bifenthrin Cyhalothrin Cypermethrin
Cowpea Curculio	Pyrethrin Neem oil extract	Bifenthrin Cyhalothrin Cypermethrin
Lesser Cornstalk Borer		Bifenthrin Cyhalothrin Cypermethrin
Lima Bean Borer		Bifenthrin Cypermethrin
Mexican Bean Beetle	Pyrethrin Neem oil extract	Bifenthrin Cyhalothrin Cypermethrin Malathion
Spider Mites	Insecticidal soap	Malathion Bifenthrin
Stink bug  Tarnished Plant Bug	Stink Bug Traps*	Bifenthrin Cyhalothrin Malathion
Japanese Beetles	Pyrethrin Neem oil extract	Bifenthrin Cyhalothrin Cypermethrin
Cucumber Beetle	Pyrethrin Neem oil extract Soil drench with parasitic nematodes to control larvae	Bifenthrin Cyhalothrin Cypermethrin
Grasshopper		Bifenthrin Cyhalothrin Cypermethrin Malathion
Lygus Bugs		Bifenthrin Cyhalothrin Cypermethrin Malathion
Whiteflies	Insecticidal soap	Bifenthrin Cyhalothrin Cypermethrin
Cutworms	Protective collars Molasses & grain bait with B.t.	Bifenthrin Cyhalothrin Cypermethrin

Insecticide For Peas

The green pea is a delicious, nutritious vegetable that can be used in a wide variety of recipes. However, it also has a tendency to attract insects. The best way to keep your peas free of bugs is to use insecticide for peas.

The most common type of insecticide for peas is called spinosad. This chemical is made from a naturally-occurring fungus found in soil and plants. The fungus produces chemical compounds that are toxic to insects, but not harmful to humans or other mammals. The chemical kills by disrupting the insect’s nervous system, causing paralysis and then death.

Spinosad works by attaching itself to certain proteins found in insect cells; these proteins are known as nicotinic acetylcholine receptors (nAChRs). These receptors are responsible for relaying signals between nerves throughout the body; when they’re blocked by spinosad, the insect cannot move properly or breathe normally and dies quickly as a result.

Another type of insecticide for peas is pyrethrins, which are derived from chrysanthemum flowers (they’re used in pet shampoos!). Pyrethrins are typically applied directly onto the plant where they work by attacking nerve endings directly; they don’t kill quickly like spinosad

List Of Insecticide For Peas