MANAGEMENT OF TOMATO PINWORM*
Management of tomato pinworm populations depends on culture
practices, the use of sex pheromones for adult moth mating
disruption, monitoring and insecticide applications where
needed. A host-free period is required to reduce tomato pinworm
levels after final harvest of the current season’s crop;
the longer the host-free period, the greater the reduction in
tomato pinworm population. A host-free period is when old
tomato plantings have been disked under and other infestation
areas such as greenhouse seedlings or alternate hosts (eggplant
and nightshade) have not been present to support tomato pinworm
populations. All crop residue and culls should be disked to a
depth of at least 2 to 4 inches, immediately after harvest is
complete, to destroy larval food sources and pupae in the soil.
Wherever possible, destroy infested crops before a new tomato
crop is planted in adjacent fields. Transplants also must be
checked before planting as field infestations can occur from
infested transplants. This product may be used in an IPM
program in conjunction with insecticides in areas of high
pressure, where migration from adjoining fields is occurring,
or where control of secondary pests is needed.
*Integrated Pest Management for Tomatoes, University of
California. Pub 3274 1990
TOMATO PINWORM BIOLOGY *
Tomato pinworm (Keiferia lycopersicella) is a widely
distributed pest of tomatoes, and to a lesser extent, eggplant,
throughout the tropical tomato-producing areas of Mexico, and
the states of Florida, Texas and California. It is a major pest
of cherry, fresh market and processing tomatoes wherever
winters are mild and production seasons are long. The tomato
pinworm overwinters primarily in tomato plants not destroyed
after fall harvest and does not undergo an obligatory diapause
during winter months. As many as 7 or 8 overlapping generations
may occur each year and these generations vary in length from 3
to 4 weeks in summer months to 3 or 4 months in winter. Adult
moths are primarily nocturnal. Mating occurs soon after
emergence and generally takes place between 4 PM and 10 PM.
Females lay most of their eggs within two days. Eggs are laid
singly on undersides of leaves. Hatching larvae may chew into
the leaf to form a narrow mine or bore into the fruit, most
commonly directly under the calyx. Late instar larvae mining in
leaves expand the mine into an irregular blotch. The larvae
then fold a leaf section over the mine and fasten the edge to
form a shelter for pupation. Mature larvae may also exit the
leaves or fruit to pupate on the ground or in the soil in
loosely constructed silken cocoons dotted with plant debris and
soil. Larvae may also enter the fruit at any stage of ripeness
where they tunnel into the core and solid portions between
locules. In heavy infestations several larvae may occur in a
single fruit. The entire larval development time may be
completed in as little as 10 days in summer. Damage to leaves
from larval feeding usually is not significant except when
heavy infestations defoliate young plants. Infestations in
spring crops may be heavy following mild winters, especially
where nearby fall plantings were not disked under after
harvest. Larva boring and feeding in the solid parts of the
fruit, particularly under the calyx, cause blackened tunnels
and fruit decay. Initially, feeding is hard to detect. However,
by the time larvae are nearly mature, a brownish, granular
frass usually exudes from under the edge of the calyx. Damage
from larval feeding may occur in both green and ripe fruit and,
because it is difficult to detect, may create a post harvest
contamination problem. The larval habit of feeding mainly under
the calyx is very difficult to detect in cherry tomatoes that
are picked and marketed with the calyx attached.
* Integrated Pest Management for Tomatoes, University of
California. Pub 3274 1990
