borer adults are black beetles with a bright orange mark right
behind the head. Two or three black spots dot the orange area. These
long-horned beetles are slender, about one-half inch long, and their
antennae are roughly as long as their bodies. Adults become active
in late spring, and females lay their eggs singly on the new growth
at the tip of the cane. They make a double row of punctures around
the stem that are three-quarters to one inch apart, and then use a
needle-like ovipositor to insert an egg between the rows deep into
the pith or center of the stem. The tips whither and die because the
double row of punctures cut off the flow of water
and nutrients to infested tips.
Larvae begin tunneling through the pith toward the base of affected
canes as soon as they hatch, but entomologists have observed
conflicting behavior. Some have observed the larvae make it to the
base of the cane in a single growing season, while others have
observed them move just an inch or two below the double row of
punctures during the first season, and only make it to the base of
the cane the following year. The white, legless larvae grow to
three-quarters of an inch long. Their tunneling activity weakens
infested canes, and often causes them to die before the fruit they
bear has a chance to mature. Control options stress pruning out
wilted tips several inches below the double row of punctures by
midsummer, and pruning out old, unproductive canes anytime.
Red-necked Cane Borer
The red-necked cane borer takes its common name comes from the
reddish area behind the adult insect's head. These otherwise black
beetles are active from late May until early August. They have much
shorter antennae than raspberry cane borer adults, and grow to about
one-quarter inch long.
Adults can be seen feeding on raspberry foliage during the day.
After feeding for several days, females lay their eggs on the
raspberry canes' new growth. These hatch in four to twenty-four
days. Newly hatched larvae tunnel into the cane where they make
winding tunnels under the bark as they work their way into the pith.
Their activity results in irregular swellings or galls that range
from one to three inches long. The bark often splits above these
galls, which can be found anywhere along the cane, although it is
quite common to find them at ground level.
The larvae grow to about three-quarters of an inch long, and are
creamy white and legless, with a pair of dark "pincers" on the last
abdominal segment. Infested canes often break off at these
swellings, and/or are weakened so much that they die. Larvae
overwinter inside the canes, pupate the following spring, and hatch
out as adults in late May or early June. The adults chew a
"D"-shaped exit hole to emerge from the cane, a characteristic
shared by the related bronze birch borer and emerald ash borer. The
primary control for red-necked cane borer is pruning out infested
stems any time from late fall until early spring. Live larvae are
not usually found in the galls.
spot on roses - Control methods
Rot on Tomatoes