Virginia Entomologist 5:1998


Insects of Note this Week:

A Southern Red Mite sample arrived early this year. The mites were active last week. Look for stippling and mites on broad leafed evergreens such as camellia, holly, rhododendron, and others. Treat with kelthane or insecticidal soap as soon as mites are found on the foliage. These mites usually feed on the underside of the leaves.

Black Vine weevils will show up inside houses at this time of year if the plantings near the house have their root infested with immature stage of the weevil. These weevils are black with yellow spots and chew notches in leaves of plants and shrubs. See:

http://www.ext.vt.edu/departments/entomology/factsheets/blakvine.html

Oak Eriococcin is a white scale some times found on Oak. The scales are 1/4 inch long, somewhat hemispherical and oval in shape and solid white. They often pile up in clusters on small twig crotches. Treat with dormant oil in the winter for the best control.


Insects to be on the Lookout for in May

Eric Day Manager, Insect Identification Laboratory

Insect:Host(s)      Description                   Treatment timing*
 
FIELD AND VEGETABLE CROPS
 
Aphids:            Look for small soft-          Cut out and destroy small
Any crop but in     bodied insects causing        localized areas on plants or
particular cru-     the leaves to be stunted,     treat with an insecticide
cifer crops         yellowed, and/or curled.      labeled for aphids and that
                                                  particular crop.
 
Black Cutworm     Medium to large cater-        If more than 5% of the plants
and other           pillars cut off plants        are cut, control with an
Cutworms:           at the base. Inspect          insecticide or bait is
Many crops but      newly planted seed beds       warranted.
in particular       and newly set plants.
corn
 
Flea beetle:      Small black beetles jump-     Spray with Sevin when damage
Corn, eggplant,     ing like fleas when dis-      becomes severe.
and many other      turbed form the leaves of
crops               a plant. They scrape the
                    upper epidermis layer off
                    the leaf and sometimes the
                    fruit, leaving a brown scar.
 
Imported           Velvet green caterpillars     Treat when caterpillar
Cabbageworm:      with a faint yellow stripe    populations reach a threshold
Cabbage, broc-      down 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         Full grown larvae are about
other crucifers     32 mm (1-1/4 inches) long.
 
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 effective
                                                  because there is usually only
                                                  one generation of maggots and
                                                  the second planting is not
                                                  attacked.
 
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.
cherry, peach,      to the core. Adult moths
plums, apricots,    are grayish-brown with
and similar fruits  irregular golden brown lines
are attacked        on the forewings. 1/2-3/4"
                    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          dust.                         oil applied at the 1/2" green
trees and                                         leaf stage or earlier in the
shrubs.                                           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 pro-
                    blem on trees with exces
                    sive shoot growth due to
                    overfertilization.
 
Spotted Tenti-    Young mines are serpentine    Treat young mines with Vydate
form Leafminer:   changing to oval. As the      or Lannate if more than 3
Apple               larvae get older they form    mines per leaf on average.
                    the leaf into a tentlike
                    structure.
 
ORNAMENTAL INSECTS
 
Azalea Stem       Look for tips dying back      Treat mid-May and mid-June
Borer: Azalea,     and yellow legless grubs      with an insecticide or cut
rhododendron,       up to 1/2" long boring in     out and destroy dead and
mountain-laurel,    twigs and trunk.              dying tips as noticed.
Use of
blueberry                                         a borer paste in the holes
                                                  will give some control also.
 
Boxwood            Adults are out April to       Apply insecticides for
leafminer:         early May. Infested leaves    adults; apply systemic
Boxwood             often appear blistered and    insecticides in early to
                    discolored. See the March     late June to control larvae.
                    1990 issue of the Plant
                    Protection Newsletter for
                    more information.
 
Bronze Birch      Look for the top of the       Treat mid-May, and early-,
Borer: Birch,      tree dying back and up        mid-, and late-June; spray
cottonwood,         to 1" long flat-headed        trunk and branches heavily
poplar, aspen       borers under the bark.        and leaves lightly.
 
Camellia Scale:   Scale is light to dark        Treat May 10 and 20 and/or
Camellia            brown, 1/10" long and         Sept. 10 and 20.
                    oyster-shaped. Crawler
                    dates are May 1-June 5;
                    and Sept 15-30.
 
Dogwood Borer:    As many as 50 white cat-      Treat mid-May, repeat at
Dogwood, some       erpillars with brown          6 week intervals 2-3 times.
times pecan         heads living under rough-
                    ened areas of the bark.
 
Dogwood Twig      A slender lemon-yellow        In early to mid-May, apply
Borer: Dogwood     beetle grub feeding in        an insecticide spray to
elm, viburnum,      the center of twigs. As       control the adults. Prune out
and many fruit      it feeds it makes small       and destroy infested twigs.
trees               holes to the outside for
                    the protrusion of frass.
 
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
cherry              shiney as if varnished.       to retain the insecticide.
                    The small black hairy
                    caterpillars will hatch
                    out in April and feed on
                    the newly emerging leaves.
 
Elm Leaf           Newly hatched larvae are      Control newly hatched larvae
Beetles: Elm       yellowish with black mark-    in late-May and early-June.
                    ings, adults are olive
                    green with two black lines.
 

More soon in the next update.


Eric Day
Insect Identification Laboratory
Department of Entomology
215 Price Hall
Virginia Polytechnic Institute and State University
Blacksburg, VA 24061-0319
(W) 540-231-4899
Fax 540-231-9131

See my lab homepage:

http://www.ento.vt.edu/Facilities/OnCampus/IDInfo.html