POTATO INVESTIGATIONS LABORATORY
Mi- 2 \ Hastings, Florida
Mieer t -2* October 1
COOL OF INSECTS ATTACKING IRISH POTATOES IN THE HASTINGS AREA
R. B. Workman, Assistant Entomologist
SLight trap collections of southern potato wireworms for the last four
years numbered over 27,000, 71,000, 124,000, and 148,000 respectively. Wireworm
damage occurred in several locations last year.
POTATO TUBERWORM: Potato tuberworms were found in the field at Hastings last
season for the first time on record. Tuberworm and wireworm injury to potatoes are
often confused because the entrance holes of the two insects are alike after the
tubers are washed. Inside the potato, tuberworm tunnels are generally long and
winding, silken lined, and contain considerable frass. Wireworm tunnels are usually
short, straight or curved somewhat, contain little frass, and are not silken lined.
The tuberworms are dark-headed, pinkish-wihite to gray caterpillars which are about
-- inch long when fully grown. The adults are small grayish-brown night-flying
moths. Tuberworm injury appeared to be scattered throughout the Hastings area last
season judging from tuber samples collected at various graders. Contributing
factors in the tuberworm outbreak were unseasonably hot and dry weather and a
general lack of spraying due to low numbers of aphids. Insecticides for the
control of aphids on potatoes are effective against the potato tuberworm. Soil
treatments for wireworms have given only partial control of tuberworms in tests at
the Potato Investigations Laboratory. Tuberworms may tunnel in the stems and leaves
but are most injurious to the potato tubers. Whether tuberworms will be present
during the 1962-63 season is not known. Spray if tuberworms are noticed webbing the
leaves together and make weekly applications during setting of tubers until harvest
for the most effective control.
INSECTICIDES RECOMMENDED FOR CONTROL
L OF IRISH
POTATO INSECTS IN THE HASTINGS AREA
Parathion is not effective
against aphids on potatoes.
To soil and foliage when
Rarely occur in area.
Preplanting soil treatment
If other concentrations or formulations are substituted, adjust the amount speci-
fied accordingly. Follow the safety precautions on the insecticide label at all
times. Do hot leave insecticides within reach of irresponsible persons.
*Revision of Mimeo Report 61-2.