DOGWOOD BORER (Thamnosphecia scituld).
A white caterpillar with a
brown head, larva of a clear-wing moth, works in cambium of
flowering dogwood, often causing death of limbs. Remove outer dead
bark where borers overwinter and keep bark smooth at base of limbs.
Paint with DDT.
DOGWOOD TWIG BORER (Oberea tripunctata).
This common twig girdler
is a yellow grub, larva of a long-horned beetle. It works in the
center of twigs, which die back to that point, and in elm as well as dogwood. Prune twigs above the grub.
EUROPEAN CORN BORER (Pyrausta nubilalis).
This is a widespread and
destructive pest, not only to corn, with losses in the millions each
year, but to many other herbaceous plants. The borer, a flesh-colored
caterpillar with a dark head and black dots, about an inch long, winters
in old stalks and pupates in spring. Yellowish-brown moths, emerging
from June to August, lay eggs in clusters on underside of corn or other
leaves. In about a week young larvae start feeding in the developing leaf
whorl and on the tassels, then tunnel downward in the stalk and into
the ears. Tassels are broken, stalks bent, and there are sawdust castings
from holes in the stalk. The corn borer is frequently found in dahlia
Control. Dust with DDT or Ryania, directing it into center of whorls.
Promising new chemicals include heptachlor and lindane. Clean up and
burn all old corn and dahlia stalks.
FLATHEADED APPLE TREE BORER (Chrysobothris femorata).
Trees are killed
in the nursery or the first few years after transplanting, the borer
being more important on deciduous shade trees than on apples. The
yellow-white grub, 11/4 inches long, is distinctive for the broad, flat enlargment of the body just back of the head and a habit of lying with its
body curved to one side (Figure 15A). The beetle is gray to brown with
a blunt head, 1/2 inch long. The burrows are broad but shallow, packed
with sawdust, on main trunk and branches, often on the sunny side.
Large areas of bark are killed or trees girdled.
Control. Wrap trunks after transplanting, winding strips of tar-lined
paper, heavy wrapping paper, or several layers of newspaper spirally from
the tree crown, always overlapping half the strip; hold securely by winding twine in the opposite direction. Wax emulsions, antidessicants, are
sometimes suggested in place of wrapping. The wrapping should be
maintained for 2 or 3 years and new trees kept growing vigorously by
proper feeding and watering. Trees that have not been wrapped can
perhaps be saved by going after the borers with a knife.