DESCRIPTION OF PINWORMS
The adult is a
rather non-descript, small greyish-white moth that lays its eggs on
the undersides of the leaves of tomato plants (occasionally
eggplant, potato and weeds in the nightshade family). Adults are
active at night, so they go unnoticed.
When the eggs
hatch, the small yellow-grey larvae mine into the leaf and create a
blotch-type mine that has a papery appearance. Older larvae may be
yellow, green or grey with dark purple spots. They fold leaves over
or web leaves together, and live and feed inside. Older larvae also
tunnel into the stems and fruit. In large infestations, they can
cause significant damage to the fruit, although it is usually
confined to the core and the rind. Mature larvae drop to the ground
and pupate near the soil surface. There are multiple generations a
year, with seven to eight common in their native range.
be more severe in home gardens and in organic production where
regular pesticide applications are less likely than with
conventional commercial producers. Insects that feed inside plant
tissue are more difficult to control than those that feed
externally. Management focuses on prevention and sanitation. Be sure
to clean your garden out thoroughly this fall.
To be on the safe
side, bag up and dispose of spent tomato plants with the trash
rather than composting them. Even though they will not survive a
“normal” Pittsburgh winter, do not take the chance.
transplants for signs of tomato pinworm and avoid purchasing those
that are symptomatic. Once plants are in the garden, monitor your
garden regularly for signs of mined or folded leaves. Pick them off
and send them out with the trash. The only insecticide
recommendation I could find that is suitable for home gardeners is
for products containing spinosad such as Captain Jack’s Deadbug
Brew. While spinosad is not a systemic product, it does move into
the leaves enough to provide some control of leafminers. It may help
control the small larvae.