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D. Staples · 08-11-2007, 08:29 PM posted to rec.gardens

wrote:
Hi,
I am emailing from Houston, TX. Recently my neighbor discovered
hundreds of caterpillar like insect larvae on his pine tree. They are
about 1/2 inch in length, yellow-ish with black dots on their back.
There seem to be a few leg-like structures near the head. I did my
google search and am leaning towards 'pine sawfly larvae' as the
closest match.
The tree is deteriorating. It's losing its needles, and some branches
are completely free of needles. He treated the tree with a spray
insecticide yesterday (sorry, don't know which one).
My questions, is it likely to observe pine sawfly larvae in November
in Southern Texas? I am afraid I miss-identified the problem. Is there
anything else we can do, in particular to prevent the spreading of the
insect from one tree to the next (which, in this case, would be
mine....).
Thanks,
Tim.

Pine sawfly for sure. Four or five generations of this sawfly may occur
each year. Adult females begin to lay eggs in slits cut in the needles
during late March. The eggs hatch in 10-21 days, and the larvae feed
for about five weeks. When mature the larvae usually crawl to the
ground and spin a cocoon in the loose litter at the base of the tree.
The peak adult emergence occurs in late summer. Larvae from this late
summer generation are responsible for most of the damage which, although
never directly responsible for mortality, may predispose the trees to
attack by other insects.

Natural control factors generally bring outbreak populations under
control after one season. As noted, sanitation under the stems through
out the summer will reduce or destroy the population.