'F6 (6 ~' POTATO INVESTIGATIONS LABORATORY
Mimeo Report 62-4* October 6, 1961
CONTROL OF INSECT PESTS OF CRUCIFERS IN THE HASTINGS AREA
Ralph B. Workman, Assistant Entomologist
Most cases of ineffective insect control have resulted from poor application, using
the wrong material, or not waiting long enough for the insecticide to work. For the
best results in producing insect-damage free cabbage the following should be
1. Application.- Insecticide coverage must be thorough. Most insect infestations
on cabbage begin in the curled leaves of the developing head or on the lower sur'fac?
of the bottom leaves. The insecticide must contact all of these surfaces to be
2. Timing.- Insects are easiest to kill when small. Large loopers and "aphid heads"
cannot be controlled effectively. Best control is achieved when the insect, the
infestation, and the plant are small.
3. Dosage.- The recommended dosage is adequate if coverage is thorough. Larger
plants require a larger amount of insecticide mixture. Increased dosages increase
costs, safety risks, and residues. If dosages of insecticides are increased, also
increase the time limitation before harvest.
4. Equipment.- All above ground parts of the plant must be covered with insecticide.
Drop nozzles must be low enough to hit the lower sides of the bottom leaves. The
upper nozzles must be located directly over the cabbage plant for best penetration
of insecticide to the head and wrapper leaves. Lots of fog behind a machine does
not mean a good job. Examine the plants to see where the insecticide has been
deposited and make adjustments as necessary.
Cabbage insects are most numerous during the early and late (warm) parts of the
season. Weekly applications of insecticides at these times are most effective.
During mid-season when it is cool, insect activity is low. Insecticide applications
biweekly or when insects are present will give adequate protection.
Endrin has been one of the best materials for control of green peach aphids, cabbage
worms, and loopers in tests at the Potato Laboratory. Use it twice at about two
week intervals at the start of the season then switch to one of the other chemicals
at weekly intervals or biweekly if you are getting good control. If control does
not appear satisfactory, wait at least three days and check once more before
retreating. To control worms on mature cabbage use increased gallonages so that
the insecticide will run down to the lower parts of the plant. Dusts aprcp eqt.Lye
due to settling.
In Table 1 emulsible insecticides only are listed. If other concern ions or
formulations are used, adjust the amount specified accordingly. Du iy be i
substituted at the rate of 20-35 pounds per acre. Growers using hi concentrationo
dusts should be very careful not to exceed recommended dosages as h h.\esidues ma ,
result. For example, 35 lbs. of a 2% dust contains .7 Ib. or 11.2 o actual
insecticide and 35 lbs. of a 10% dust contains 3.5 lbs. of actual inse' : For
sprays use from 50-100 gallons of water or more depending on plant size. der-
stickers have improved aphid control but not worm control in tests at the Potato
Laboratory. Use sparingly. Excessive spray runoff indicates a loss of insecticide
on the plant.
*Revision of Mimeo Report 61-1.
Observe the safety precautions on the insecticide label at all times. All
insecticides are safe if used correctly. Some of the major causes of pesticide
accidents are: (1) failure to read and follow the use precautions on the label;
(2) leaving the material within reach of irresponsible persons; (3) carelessness in
disposal of the empty containers. Do not use any of the insecticides listed in
Table 1 around or inside the house or barn without making sure that it is
recommended for such purposes.
Table 1.- Insecticides Recommended for Control of Cruciferous Insects in the
Insecticide :Amount Actual Minimum days
Insect I(E=Emulsible) per acre insecti- before Notes
rpt cide harvestI
Cabbage Parathion 4E 1-1 pt. 4-8 oz. 7-- pt.,lO-1 pt. Clean up infested plants
aphid Phosdrin 2E 1 pt. 4 oz. 1-cab., broc. early in season. Check
1 3-cauliflower transplants. Parathion
Systox 2E 1 pt. 6 oz. 21 control may be erratic.
Green Endrin 1.6E 1 pt. 3.2 oz. 35 Found on undersides of
peach Parathion 4E i-1 pt. 4-8 oz. 7-- pt.,10-1 pt. lower leaves. Primary
aphid Phosdrin 2E 1 pt. 4 oz. 1-cab., broc. source of aphids on
Cabbage Endrin 1.6E 1 pt. 3.2 oz. 35 Some insecticide should
worm, Parathion 4E ji-1 pt. 4-8 oz. 7- pt.,10-1 pt. contact soil on top of
Cabbage Phosdrin 2E 11 pt. 4 oz. 1-cab., broc. rows to kill insects
looper, 3-cauliflower crawling on surface.
Cutworm Toxaphene 8E 1-2 pt. 1-2 lb. 7
Leaf- Parathion 4E -1l pt. 4-8 oz. 7-1 pt.,10-1 pt. Rarely occur in area.
miner Rarely occu
Mole Aldrin 4E 1j t. 1 lb. NTL2 Apply to soil surface
cricket Chlordane 8E 1 qt. 2 Ib. NTL2 before planting.3
lWhen outer leaves are removed at harvest.
2No time limitations.
3After planting, regular foliage sprays for cabbage worms will prevent the
establishment of mole crickets.
Do not apply endrin or toxaphene to broccoli or cauliflower after edible parts
begin to form.