Mimeo E-80
October 1961
Purdue University
Agricultural Extension Service
Department of Entomology

Insect Control on the Dairy Farm
Contamination of milk and dairy products with insecticides, or with any other material for that matter, is prohibited by federal law. The state of Indiana and many municipalities have similar regulations. Contamination can occur if the wrong insecticide is applied to the animals or used to spray bams or other buildings where milk is handled. Likewise, forage crops and
other feeds will result in milk contamination if treated with a prohibited insecticide or if the required number of days has not elapsed between treatment and pasturing or harvesting of the crop. The following tables list those insects of greatest concern to dairy farmers along with chemicals approved for control, methods of application and restrictions, if any.
INSECTICIDES APPROVED FOR USE ON LACTATING DAIRY ANIMALS
Insect	Control with:	How to apply	Purdue ref.
Face fly	0.5% DDVP bait	Apply daily to the animal's head, according to directions on the container.	Mimeo E-12
	Synergized pyrethrins. (Often formulated with additives or repellents.)	Spray daily directly into the cattles’ faces with hand equipment or with an automatic sprayer. The latter is most effective when set up so that cattle spray themselves in the morning as they leave the milking parlor. Follow directions of the manufacturer.	Mimeo E-12
House fly Horn fly Stable fly Horse fly Deer fly Mosquitoes	Synergized pyrethrins (as above)	Apply directly on the cattle at milking time or use in automatic sprayers. Automatic devices can be set up in the bam or in a fence or lane so that cattle pass through them on their way to water or pasture. Follow directions of the manufacturer.	Mimeo E-12
Horn fly	Methoxychlor 50% powder or malathion 4% dust	Apply one heaping teaspoonful of 50% methoxychlor powder as a dry dust to the back and shoulders of cattle, and repeat at 3-week intervals. A malathion 4% dust can be used in a like manner but at the rate of 4 heaping tablespoonfuls per animal repeated at 2-week intervals. Apply either material after milking.	Mimeo E-12
Cattle lice	Rotenone or synergized pyrethrins	Spray in fall with synergized pyrethrins or with 2 pounds of 5% rotenone spray powder plus a small amount of detergent in 100 gallons of water. Repeat in 14 days, or dust often with 1% rotenone.	Mimeo E-13
Cattle grubs	Rotenone	Mix 7 1/2 pounds of 5% rotenone spray powder in 100 gallons of water. Add a small amount of detergent, and apply to backs of the animals at high pressure with a power sprayer. Treat when first lumps appear, and repeat in 30 and 60 days. A 1 1/2 percent rotenone dust can also be used if rubbed into the grub openings with a stiff brush.	Mimeo E-13
Flesh maggots	Lindane or Diphenylamine	These materials are contained in small amounts in wound dressings. This is the only way that lindane can be used on dairy cattle.