Strawberry Sap Beetle
Stelidota geminata
Biology
Adult strawberry sap beetles, Stelidota geminata,
are less than 1/8 inch long, oval-shaped, and mottled brown in color.
They fly into strawberry plantings from wooded areas at about the time
berries begin to ripen; they are particularly attracted to over-ripe
berries.
Damage
Their feeding leaves deep cavities in berries, and
females then deposit eggs on the injured fruit. Although larvae feed in
berries, they usually are unnoticed because the fruit has already begun
to decompose as a result of damage caused by adults. Because over-ripe
fruit is especially attractive to sap beetles, damage is often greatest
in U-Pick operations where pickers leave large numbers of ripe and
over-ripe berries in the field.
Control
Strawberry sap beetles are best controlled by
timely and complete ("clean") picking and the removal of over-ripe and
damaged berries. Because sap beetle populations usually do not build up
until the picking cycle is underway, the use of insecticides is limited
by frequent harvests. Certain insecticides are effective against sap
beetles but can be used in strawberries only if the preharvest interval
of 3-5 days is obeyed. Placing "trap buckets" of over-ripe fruit outside
field borders can intercept immigrating beetles and reduce numbers in
the crop.