Insect:Host(s) Description Treatment timing* FIELD AND VEGETABLE CROPSBlister Beetles: Slender beetles 1-2" in Beetles usually appear sud- Potato, tomato, in length which may be denly and may cause much black melon, eggplant, with white margins or black damage before they are sweet potato, and yellow striped. They detected. Spot treatments bean, pea, and feed on the flowers and when they are found will many other crops foliage. give good control. Cabbage Looper: Green larva with three Insecticide applications Crucifers sets of prolegs and white made on 7-day intervals are stripes running the length necessary to control this of its body. When it crawls insect. it moves like an inchworm. Colorado Potato Adults are yellow with For small gardens, beetles Beetle: brown stripes, they are can be removed by hand- Potato, tomato, oval-convex in shape. The picking; larger areas or eggplant,pepper, larva is yellowish red or heavy infestations will tobacco, and orange and has a row of require the use of insect- other solan- black spots along each side icides. aceous plants of its body. Corn Earworm: Earworm larvae have a wide On sweet corn treat Sweet corn and range of colors, from during the period from tomatoes pri- pale yellow to dark brown; silking to harvest to marily, but will many are greenish. They protect the ears. Resistant feed on over 100 all have pale stripes and varieties are available. different host orange-yellow heads. Tomatoes should be treated plants after the plant sets fruit. Cowpea Curculio: This weevil is 1/4" long, Late planted crops tend to Beans and peas blackish-bronze in color, be less severely attacked. and has a humpbacked Crop rotation and sanita- appearance. Adult beetles tion also help in control. puncture the pods and lay Commercial beans will need eggs on the seed. This chemical control starting insect tends to be a when blooms first appear. problem in home gardens and minor in commercial plantings. Insect:Host(s) Description Treatment timing* Cucumber Beetle: Two beetles feed on cucur- Foliar sprays may Cucumber, can- bits in Virginia, the be necessary in some spotted taloupes, gourd, cuc. beetle is pale green cases. To prevent bac- with squash, and black spots on its wing terial wilt, treat when 1 watermelon are covers; the striped cuc. beetle per 100 row feet preferred hosts. beetle is pale green with is found. They are found black stripes on its wing on other crops covers. Both transmit but are not as bacterial wilt of cucurbits. important. European Corn On corn look for shot-hole Treatment on field corn is Borer: Many damage in the whorl warranted if more than 50% late-June crops but in and early-July. In of the plants have an egg addition, particular corn look for the flattened egg mass. Count 50 random plants masses with eggs and if the average overlapping like fish scales on the number of egg mass under- sides of the leaves, look exceeds 0.5 then treatment may from the first of July to be necessary. Treatment must be mid July for the egg made just after egg hatch. masses. Be sure to scout the inner Growers in Virginia usually parts of the field because treat between the first the border rows tend to and fifteenth of July have have higher populations of when necessary. ECB. Fall Armyworm: Tan to dark larvae with For corn and sorghum treat when Corn and other light colored longitudinal 80% of the plants have at grasses as well stripes on its back, as least one caterpillar, or if as many well as an inverted "Y" there are two or more cater- vegetable crops on its head. Start scouting pillars, treat corn when 40% late July and August. infested and sorghum when 50% infested. Flea beetle: Small black beetles jump- Spray with Sevin when damage Eggplant ing like fleas when dis- becomes severe. turbed from the leaves of a plant. They scrape the upper epidermis layer off the leaf and sometimes the fruit leaving a brown scar. Insect:Host(s) Description Treatment timing* Grasshoppers: The Differential Grass- Avoid mowing border areas All crops hopper is dark green with with heavy grass and weed yellow bands. The Red- growth, grasshoppers will legged Grasshopper has red move from those areas to legs. Grasshopper damaged the crop plants after their leaves are jagged and host plants have been cut tattered. down. Treat with an insecticide if damage becomes severe. Imported Velvet green larvae with a Treat when caterpillar Cabbageworm: faint yellow stripe down populations reach a threshold Cabbage, broc- the back and a row of of one worm per plant, repeat coli, cauli- yellow spots on each side. every 5 to 7 days as needed. flower, and other crucifers Mexican Bean Adults are hemispherical Insecticide applications Beetle: in shape and yellowish- are recommended if more Bean crops brown in color. They have than 30% defoliation takes black spots on the wing place. covers. The pale larvae are less then 1/2" long and have many spines. Spider Mites: Damage is more noticeable Mites tend to be a dry Over 180 host than the mites themselves, weather problem. Treat plants including look for yellow stippled with a miticide if leaves many weeds, soy- that often take on a sand- dry conditions are beans and other blasted appearance. Shake expected to continue. beans tend to be the leaves over a piece of hard hit paper and look for small pale mites crawling around. Stink Bug: Barrel shaped eggs are Removing weedy growth that Many crops but laid on the undersides of harbors stink bugs will cut in particular leaves, nymphs are black down on native breeding pepper and and white or red or green. sites. Spot treatments of tomato Adults are green or tan. insecticides when stink All stages have piercing- bugs are seen is recom- sucking mouth parts. mended. Damage to pepper and tomato appears as white halos and deformations on the fruits. Insect:Host(s) Description Treatment timing* Squash Bug: Nymphs are grayish white Handpicking works well All cucurbits; with dark heads and appen- in small gardens. Chem- squash bugs pre- dages. Adults are oval ical control might be fer squash, elongate, light gray, and needed in larger pumpkin, cucum- mottled yellow on the operations. ber, and melon underside. Nymphs tend in that order to be found on the basal portions of the vine. Squash Vine Plants suddenly wilt and Borers can be cut die, Borer: the plants on close exam- out with a sharp knife in Primarily squash ination have white grub- small plantings, heavily and pumpkin, but like caterpillars boring infested plants should be other cucurbits into the basal portions of pulled out. Large plan- are occasionally the vine. tings may need insecticide fed upon applications made at the base of the plants. Thrips: Small slender yellow This insect tends to be a Wide range of insects feeding on the problem when plants are stressed field crops, flowers and foliage. and insecticides are Damaged vegetable crops, foliage tends to be spotted only recommended if poor and floral crops with white when heavily fed conditions are expected upon and damaged flowers to continue. are brown and tend not to to open. Western Corn Pale cream colored larvae Control for adult silk clip- Rootworm: tunnel and feed on the ping is justified if there are Corn (only) roots. The more conspicuous an average of 5 or more beetles adults feed on the silks per plant and the silk clip- during July and August. ping is observed before 75% of The adults are pale green the plants have silked. with three black stripes on To determine the need their wing covers, some- for a soil insecticide next times the black stripes year examine 50 random are fused together to make plants from throughout the the wing covers appear field and count the total solid black. They are about number of beetles on the entire 1/4 inch long. plant. If the average number of beetles exceeds 1 per plant then you may want to consider using planting time soil insecticides or rotating to another crop. Insect:Host(s) Description Treatment timing* Whitefly: Small dusty white flies Insecticidal control is Many vegetable found in the underside of recommended for large pop- crops, but the leaves. Pale nymphs ulations. tomatoes tend to are also found on the under- be hard hit. sides of the leaves. Their feeding causes the leaves to become mottled with yellow. FRUIT INSECTS Codling Moth: Pinkish-white caterpillars If using pheromone traps, Apple and pear enter fruit at calyx end treat if you exceed 5/trap/ primarily, but and tunnel all the way week. cherries,peaches, to the core. Adult moths plums, apricots, are grayish-brown with and similar irregular golden brown lines fruits are also on the fore wings; 1/2-3/4" attacked. wingspan. European Red Mites are very small and This mite is resistant to Mite: Apple range from red to green. many miticides, so make sure pear, plum, Foliage turns a sickly that the chemical you will use prune, and bronze color as if covered is effective. A dormant oil many other with dust. applied at the 1/2" green leaf trees and shrubs stage or earlier in the spring is important also. Green Apple Pale green nymphs on the Treat when 50% or more of the Aphid: underside of leaves and shoots are infested. Apple, pear new shoots, often a problem on trees with excessive shoot growth due to overfertilization. Lesser Peach- Look for brown pupal cases Treat immediately post- Tree Borer: protruding from wounds on harvest Peach, plum, scaffold limbs. cherry, nectarine, apricot Peach Tree Look for a mass of gum Adults emerge July- Borer: Peach, and frass at the base of September; treat immediately plum, cherry, the trunk, white larvae post-harvest. nectarine, will be found under the apricot bark from 3" below the soil level to 10" above. Insect:Host(s) Description Treatment timing* San Jose Scale: Scales are dirty gray Treat June 10-15, late-July Apple, pear, with a dark concentric cherry, and many ring on the center. other fruit trees Scales infest the bran- ches, twigs, and fruit. Variegated leaf- Eggs are laid in masses in Treat when egg masses are roller and which the eggs overlap about to hatch (dark head Tufted Apple much like fish scales. stage). Budworm: The egg masses are found Both are general on the leaves. feeders but are pests on apple and peach ORNAMENTAL INSECTS Euonymus Scale: Females are dark brown Treat May 10 and 20, Euonymus, oyster-shaped, males are and Aug. 5-15. bittersweet, and elongate and white. some ivy ground Crawler stage is May 5- covers. June 10; and Aug. 1-25 Fall Webworm: Eggs are laid in a mass Nests can be pruned out in Most fruit and of 200 to 500 often cover- early summer or if a large nut trees as ed with a woolly layer of numbers of nests exist, treat well as some scales. Large groups of mid- to late-June or when new hardwoods and larvae form a nest at the larvae appear. shrubs tip of a branch. Hickory Leaf Galls shaped like No control is needed as Stem Gall: bullets develop on the these galls do not harm Hickory petioles and shoots. the tree. Leaves with galls fall off the tree prematurely causing concern by the tree's owner. Galls are formed by aphids. Japanese Scale: Long and narrow scale, Treat at 2-week intervals Maple, privet dull white in color, from June 1-Sept. 1. often found on the trunks and branches. Juniper Webworm: Webs will usually be Prune off and destroy any Juniper and formed on on the upper active webs. Insecticide redcedar branches and will include controls, if needed, should be frass and dead needles. applied late July-early August. Insect:Host(s) Description Treatment timing* Lace Bugs: New damage will not be Lace bugs overwinter as Andromeda, oak apparent yet this year, adults on deciduous plants. azalea, walnut but last season's damage Treat in late May and repeat rhododendron, appears as stippling in June and July. On ever- sycamore and brown droppings on greens lace bugs overwinter in the leaves. the egg stage. Mimosa Webworm: Larvae feed gregariously Treat when trees show Mimosa and in a web spun over the first signs of feeding in honeylocust flowers and leaves and June. May need to repeat in later feed individually mid-July and mid-August. on leaves and pods. Obscure Scale: Scales are circular, Treat white oak in mid August. Oak, pecan, elm grayish, and closely Treat red oaks and other trees hickory, hack- resemble tree bark. They in mid July. berry can usually be found on twigs and branches. Small branches may be killed. Pine Needle The female scale is white Treat May 5-20 and/or Scale: Nearly and about 1/10" long, its July 15-20. Single in- all species of shape varies but is fested branches can be pine as well as usually wider at one end. pruned out. many other ever- The male is smaller and has greens four parallel ridges down the center. Crawler stage is April 20- May 30 and July 10-20. Rhododendron Larvae bore in the sap- Treat June 10-15, and Borer: Rhodo- wood just under the bark, July 5-10. Prune out any dendron, some- causing the branches to infested branches. times azalea and wilt and die. Adults are mountain-laurel clear-winged moths. San Jose Scale: Scales are dirty gray Treat June 10-15, July Many trees and with a dark concentric 10-15, and September 10-15. and shrubs ring on the center. Scales infest the bran- ches, twigs, and fruit. Spruce Mite: Small mites, 1/50" long, Spray with a miticide Arborvitae, cause a yellow stippling in mid-May and early spruce, juniper, on the needles and die- fall. hemlock back of lower branches. Insect:Host(s) Description Treatment timing* Yellow Poplar Small black weevils make Control the emerging Weevil/ Sas- rice shaped holes on adults in July. safras Weevil: the underside of the leaves. Yellow poplar, Larvae make blotch type mines sassafras, on the same leaves the adults magnolia fed upon. Severly damaged leaves will turn brown. White Peach The female scale is white Treat July 5-15, and Scale: Most with a yellow mark on the September 1-10. Next year fruit trees and center and has a rounded treat also May 1 and May 10. many ornamentals shape. The male is solid white and elongated in shape. Crawler stage is April 25-May 15, and July 1-15, and August 20-September 15.
* See Virginia Pest Management Guides for recommendations on insecticides and rates. Use insecticide applications only when high population levels demand control action. Most plants can support small populations of pest insects.