Ambrosia beetles are represented in the South by several species of the
genus _Platypus_ of which only _P. flavicornis_ (F.) is known to attack
dead or dying southern pines. _P. flavicornis_ (F.) will secondarily
invade other conifers and on some occasions may be found in hardwood
trees. It is so abundant in the South that few dying pines, stumps, or
logs escape attack. The beetle is found from Texas east to Florida and
north to New Jersey.
[Illustration: Adult of the _Platypus_ ambrosia beetle.]
The adult is a reddish-brown elongate beetle approximately one-fourth
inch in length. The male of the species has a pair of blunt tooth-like
structures on the third abdominal segment. Several males are usually
found in the presence of a single female. This species requires moist
wood which is favorable to the growth of fungi upon which they feed. The
adults bore into sapwood or heartwood of logs and lumber, making
pin-sized holes which are stained by the ambrosia fungus. The female
lays eggs in small clusters in the tunnel and the developing larvae
excavate tiny cells extending from the tunnel parallel to the grain of
wood. There may be several generations a year.
Ambrosia beetle damage to green sawlogs and lumber may result in
considerable degrade and strength reduction. The best control is rapid
utilization of dead or dying trees. Lumber should be seasoned as soon as
possible to reduce or eliminate losses.
SOUTHERN PINE SAWYERS, _Monochamus_ spp.
In the South, dying pines and fresh logs are quickly attacked by the
pine sawyers. In sufficient numbers they may cause a significant loss of
wood fiber and degrade sawlogs. These species are commonly found in the
South infesting southern pine, fir, and spruce wherever the hosts grow.
[Illustration: Adult southern pine sawyer beetle.]
The adults emerge in the spring or summer and begin to feed on the bark
of twigs. After mating, the female gnaws pits through the bark of
freshly felled or dying pine. The female beetle lays one to several eggs
in each pit. After eggs hatch the larvae bore beneath the bark for 40-60
days, converting the inner bark into coarse, shredded frass. The larvae
then enter the wood and make deep U-shaped cells through the heartwood
and sapwood. The entrance is plugged with frass and the far end is
excavated into a pupal chamber. The larvae pupate the following spring
or early summer, transform into adults, and emerge that same season. The
insect has two or three generations per year in the South.
Pine sawyers render storm- or fire-damaged pines unfit for salvage and
are also a problem in wood-holding yards. Rapid salvage and utilization
of dead or dying trees or green logs will reduce losses significantly.