Author: Eric R. Day, Insect Identification Laboratory, Department
of Entomology, Virginia Tech
Insects to be on the Lookout for in July
Insect:Host(s) Description Treatment timing*
FIELD AND VEGETABLE CROPS
Blister Beetles: Slender beetles 1-2" in Beetles usually appear sud-
Potato, tomato, in length which may be black denly and may cause much
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 spotted be necessary in some
taloupes, gourd, cuc. beetle is pale green with cases. To prevent bac-
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 late-June warranted if more than 50%
crops but in and early-July. In addition, of the plants have an egg
particular corn look for the flattened egg mass. Count 50 random plants
masses with eggs overlapping and if the average
like fish scales on the under- number of egg mass
sides of the leaves, look exceeds 0.5 then treatment
from the first of July to may be necessary. Treatment
mid July for the egg masses. must be made just after egg
Be sure to scout the inner hatch. Growers in Virginia
parts of the field because usually treat between the
the border rows tend to have first and fifteenth of July
have higher populations of when necessary.
ECB
Fall Armyworm: Tan to dark larvae with For corn/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
many weeds, soy- leaves that often take on dry conditions are
beans and other a sand-blasted appearance. expected to continue.
beans tend to be Shake the leaves over a
hard hit piece of 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 die, Borers can be cut
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 stre-
field crops, flowers and foliage. Damaged ssed and insecticides are
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 open.
Western Corn Pale cream colored larvae Control for adult silk clip-
Rootworm: tunnel and feed on the ping is justified if there
Corn (only) roots. The more conspicuous are an ave. 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%
The adults are pale green of 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 solid field and count the total
black. They are about number of beetles on the
1/4 inch long. entire plant. If the average
number of beetles exceeds 1
per plant then you may want
to consider using planting
time soil insecticides
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
prune, and bronze color as if covered use is effective. A dormant
many other with dust. oil applied at the 1/2" green
trees and shrubs leaf 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
frass and dead needles. be 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
the leaves. in 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
Oak, pecan, elm grayish, and closely August. Treat red oaks and
hickory, hack- resemble tree bark. They other trees 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 or when found.
hemlock back of lower branches.
Insect:Host(s) Description Treatment timing*
Yellow PoplarSmall 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.