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AGRICULTURAL RESEARCH CENTER
Mimeo Report PR-1972-3
POTATO INSECT CONTROL IN THE HASTINGS AREA
P B. Workman, Assoc. Entomologist
I USE AND SAFETY ON THE PESTICIDE LABEL AT ALL TIMES.
nsect I scticide Amount Cutoff Notes
e NOV l(S-T4sible per acre* (days)
Azodrin 3.2 20 oz. 7 Aphids on potatoes are resistant
phids Dimethoate .67E 1 pts. None to DDT, Parathion, Phosdrin, and
I.F.A.S. Unini ld, AR 2E 1 pts. 7 Thiodan.
-mn4i-. fl' 1 pt. 14
Systox 2E :l-p pts. 21
Armyworms, Azodrin 3.2E 20-40 oz. 7 Spray up to 1 week of digging
Cutworms, Lannate 90SP 8 oz. 14 for cutworms and tuberworms.
Tuberworm, Monitor hE 1 pt. 14 Hilling deeper protects tubers
Other Worms Parathion 8E pt. 5 from insects.
Phosdrin 2E 1 pt. 1
Thiodan 2E 1-2 qts. None
Leaf-Footed Guthion 2E 1 qt. 7 Guthion effective on tuberworms.
Plant Bug, Parathion 8E pt. 5
Green Phosdrin 2E 1 pt. 1
Stinkbug Thiodan 2E 1-2 qts. None
Wireworm Diazinon 4E 1-2 qts. None Preplant soil treatment. See
*Parathion 8E 1 qt. None "Wireworms" below.
Leafminer May be numerous at harvest but rarely cause damage.
Adjust dosage for other formulations.
APHIDS: The 1972 aphid outbreak on potatoes at Hastings was one of the worst in
years. High populations developed early and covered the plants in many fields.
None of the registered insecticides gave appreciable control of these heavy infes-
tations even when applied at increased rates and short intervals. However, it
appeared that where regular treatments were started about midseason, before large
number of aphids were present on the plants, excellent control was obtained.
This was the 2nd consecutive season of high aphid numbers. Populations this
coming season may be high or low.
MONITOR: Monitor is now registered on potatoes. Three years of tests at the
ARC, Hastings have shown it to be effective on aphids and worms. It is a "phos-
phatic" insecticide and, while not as toxic as parathion, should be used with care.
WIREWORMS: Light trap catches of the adult (beetle) of the southern potato
wireworm this summer were the lowest since 1959. This indicates that fewer wire-
worms will be present to attack potatoes next season. Little damage is expected
since wireworm damage has been low for a number of years. No increase in tuber
damage was noted last year from the unusually high beetle catch of 1970.
TUBERWORMS: Tuberworms are a minor pest of potatoes at Hastings causing light
damage annually. Outbreaks have occurred several times coupled with very dry
weather. Leaves, stems, and tubers are attacked. Cracked soil or a light soil
covering allows easy tuberworm access to the tubers. When soils are kept dry and
shallow for improved skin set, appreciable tuberworm damage may occur. Control is
accomplished by regular sprays during tuber growth and maturation. Preplant soil
* treatments for wireworms do not last long enough and would not protect exposed
tubers anyway. Tuberworm tunnels differ from wireworm injury by having a thickened
lining which can be removed intact from the tuber. Tuberworms are usually not
found in potatoes unless large infestations are present.