This snout beetle is very similar to the white pine weevil both in
appearance and habits. It is found throughout the south- and
mid-Atlantic states from southern New Jersey west to Missouri. Although
deodar cedar is the preferred host, Atlas cedar, Lebanon cedar, and
several species of southern pines are also attacked.
[Illustration: Galleries and chip cocoons of the deodar weevil.]
Adults emerge from April to May and feed briefly on the inner bark of
leaders and lateral branches of host trees. Heavy feeding frequently
girdles the stem and can kill small trees. The adults are dormant during
the summer, but resume activity in the fall to lay their eggs. From one
to four eggs are deposited in feeding punctures. The newly hatched
larvae bore into the inner bark where they construct winding galleries
which girdle the stem. Evidence of such infestations is often delayed
until January when the branches begin to turn brown. Winter is spent in
the larval stage. The larvae pupate in March or April and the cycle is
complete.
Keeping shade trees in a vigorous condition by proper watering and
fertilization helps reduce their susceptibility to weevil attack.
CONEWORMS, _Dioryctria_ spp.
Coneworms are perhaps the most destructive insect pests of pine cones in
the South. They are particularly serious in superior-tree seed orchards
where they frequently cause substantial economic loss. There are five
important species of coneworms in the South, one or more of which attack
all of the native and exotic pines.
[Illustration: Coneworm larva feeding on a pine shoot.]
Although the number of generations per year varies with the species,
their general life history is similar. Female moths lay their eggs
around wounds, cankers, galls, etc., but also deposit particularly on
terminal growth. Eggs generally hatch in about a week. Larvae may stay
at a single feeding site, or move to several different sites before
completing their development. This latter behavior often results in a
single larva destroying several cones or shoots. Pupation takes place in
a chamber constructed by the larva at the feeding site. Depending on the
species and time of year, the adult may emerge in two to three weeks or
overwinter in the pupal stage. Coneworms cause several kinds of damage.
They may mine through the inner bark, bore up the center of a shoot, or
completely hollow out a cone. Their attacks are sometimes marked by
fecal pellets and large pitch masses.
[Illustration: Slash pine cone damaged by coneworm larva.]
Several parasites attack coneworms but are seldom effective enough to
prevent population build-ups. Chemical control is often necessary on
seed orchards to ensure adequate protection of the cone crop.
PINE SEEDWORMS, _Laspeyresia_ spp.
Until recent years little has been known about pine seedworms. These
insects are found throughout the South but seldom have population
explosions. An exception to this is on slash pine in Florida where over
70 percent of one year’s cones were reported infested. Longleaf pine
cones in Texas and Louisiana have also had over 60 percent cone
infestation on occasion. Loblolly and shortleaf pine cones are seldom
over 20 percent infested. Seedworms have been found infesting longleaf,
loblolly, shortleaf, slash, and Virginia pine cones. _Laspeyresia
anaranjada_ Miller attacks primarily slash pine, occasionally longleaf
pine, and rarely loblolly pine. _L. ingens_ Heinrick attacks primarily
longleaf and slash pine. _L. toreuta_ Grote attacks Virginia, shortleaf,
and loblolly pine in the South.
[Illustration: Adult pine seedworm.]
The female moth lays eggs from April through May on second-year cones.
There is one generation per year. Larvae feed within developing seeds
until the cone matures. In late fall, larvae either bore into the cone
axis or remain in a hollowed-out seed, and overwinter. Pupation occurs
within the cone and moths emerge through the hollow seeds. External
evidence of seedworm attack is not visible in immature cones. As cones
mature, damaged seeds are retained in the cone. Heavily damaged cones do
not open properly. In high-value seed orchards and seed production areas
some protection from seedworm attack may be obtained through the use of
pesticides applied in a carefully timed program.
[Illustration: Pine seedworm larva in longleaf pine seed.]