Author: Eric R. Day, Insect Identification Laboratory, Department of Entomology, Virginia Tech
Insects to be on the Lookout for in April
Insect:Host(s) Description Treatment timing*
FIELD AND VEGETABLE CROPS
Black Cutworm Medium to large dark cater- If more than 5% of the plants
and other pillars cut off plants at are cut, then control with an
Cutworms: the base. Inspect newly insecticide or bait is
Many crops but planted seed beds and newly warranted.
in particular set plants.
corn
Root Maggots: White legless maggots Usually a planting time soil
Many vegetable feed on small roots and insecticide is needed but a
and field crops, tunnel into large roots. soil drench after plants have
particularly Plants with damage fail been set may be effective.
crucifer crops to develop properly. Replanting is also effective
because there is only one
generation per year and
no maggots infest the
second planting.
Fruit Insects
White Apple Look for small, pale Check several trees and
Leafhoppers: leafhoppers on the under- treat if a high density
Apple sides of leaves. This is found on all trees. If
will be the first we have a dry spring, this
generation. pest may be a problem.
European Red Mites are very small and Miticides can be used
Mite: Apple, range from red to green. during the season but
pear, plum Foliage turns a sickly this mite is resistant
prune, and bronze color as if covered to many miticides, so
many other with dust. make sure that the chemical
trees and shrubs you use is effective.
Otherwise use a dormant oil
at the 1/2" green leaf
stage.
Spotted Tenti- Young mines are serpentine Treat young mines with
form Leafminer: changing to oval. As the if more
Apple larvae get older they than 1 mine per leaf on
form the leaf into a tent- average.
like structure.
Ornamental Insects
Bagworm: Caterpillars form "bags" Pick off and destroy all
Conifers, maples around their bodies made of bagworms now and/or treat
sycamores, box- silk and plant debris. with an insecticide in mid-
elder, and many They overwinter as eggs June. Early next spring pick
others in the bags; the eggs off all bags you can find.
hatch in late May and
early June.
Boxwood Adults are out April Apply insecticides
leafminer: to early May. Infested for adults; apply
Boxwood leaves often appear systemic insecticides
blistered and discolored. in early to late June to
control larvae.
Boxwood Mite: White and gray stippling Treat in early May with
Boxwood on the upper surface of a miticide.
the leaves.
Boxwood Resemble aphids and are Spray in mid-to-
psyllid: covered with a white late April
Boxwood cottony material. They when growth
feed on the undersides has started.
of the leaves.
Cutworms Medium to large dark cater- If more than 5% of the plants
Many non- pillars cut off plants at are cut, then control with an
woody plants the base. Inspect newly insecticide or bait is war-
planted seed beds and newly ranted. Reduce weed growth;
set plants. cutworms are attracted
to weedy areas.
Eastern Tent Look for conspicuous egg Pick off egg masses before
Caterpillar: masses circling twigs. they hatch. Treat with an
Many fruit trees, These egg masses will be insecticide as soon as the
but in particular black in color and quite leaves have emerged enough to
cherry shiny as if varnished. The retain the insecticide.
small black hairy
caterpillars will hatch
out in April and feed on
the newly emerging leaves.
Iris Borer: Larvae feed below the Sprays are
Iris, native soil level on the rhizomes recommended for
blue flag and feeding damage is application in
sometimes not apparent early April.
until the plant dies or Important to
the leaves wilt. Bacterial remove and burn
soft rot often follows dead leaves,
borer damage. dried rhizomes
and damaged plants.
Juniper Scale: Crawler stage is from Treat April 10-15
Junipers April 5-22 and June and/or June 10-15
5-20. Scales have an
elongate white covering
with a yellow cap at
one end.
Pine bark aphid: The cottony masses that Treat: April,
Eastern white, the insect produces are late June,
Scotch, Austrian, conspicuous even at a mid-August.
and sometimes distance and are usually
other pines seen in bark crevices and
bases of needles.
Insect:Host(s) Description Treatment timing*
Pine Needle Crawler stage is from Treat May 5-20
Scale: Scotch, April 20-30 and and/or July 15-
mugo, and July 10-20. Scales 20.
Austrian pine, are white, elongate-
some other narrow in front and
conifers but broad in back.
usually not
damaging
Southern red Damage is seen as finely Treat: late April to
mite: Holly, stippled leaves with a early May and late
pyracantha, yellowed, chlorotic, or September to mid-
azalea, rhodo- russetted appearance. October.
dendron, camellia,
and other broad-
leaved evergreens
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.
Virginia Pine Larva is green-gray Spray mid-April.
Sawfly: Virginia with black stripes and
pine primarily, a black head capsule.
also short leaf Treatment is usually only
and loblolly needed on high value trees
pine with prior history of infestation.
White peach Crawler stage: April 25- Treat: May 1,
scale: Peach, May 15, July 1-15, July 1-15, August
locust, ash, August 20 - Sept 15 20- Sept. 15
pecan, mulberry, Female scales are white and
apple, and many circular in shape, males are
other trees and elongate.
shrubs
White Pine Look for overwintering Aphids will be scattered and
Aphid: Eastern eggs on the ends of the more abundant in some places
white pine needles; eggs are shiny than others. Spot treat when
aphids black and as many as 26 and where you find W.P.
may be found on one needle. aphids. Aphids will probably
Aphids produce large be in damaging numbers in
amounts of honeydew which late April-early May.
provides an excellent growth
medium for black sooty mold
on the needles and branches.
Sooty mold is the most
conspicuous indication
of aphid infestation.
White Pine Symptoms: resinous Treat: late-March
Weevil: Eastern bleeding on the 8 to 10 and early April.
white pine, inches of stem below the
Norway spruce, terminal bud and death
and other pines of the upright leader.
* 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.