Biology The stable fly is a very serious economic biting fly pest for confined cattle throughout the US and is becoming a serious pest for pastured cattle as well. Both sexes suck blood and prefer to feed on the lower body and legs of cattle. If enough flies are present, this may lead to reduced weight gains or milk production in dairy cows. Annual economic loss in North America due to stable flies is estimated at nearly $1 billion. Stable flies breed in many wet places, including old manure, decaying feed, calf bedding, compost, silage, etc. Stable flies will also disperse long distances from where they were bred and become significant pests of humans. The generally agreed upon economic threshold for cattle is 5 flies per leg, at which point beef cattle show reduced weight gains. Similar effects likely occur in milking cows. Management of stable flies is principally through improved sanitation and manure management. When sanitation measures are not enough to control adult populations, application of insecticides to premises or animal quarters may be necessary (see "Fly Control" section). There are a few on-animal chemical control options, listed below.
- diazinon ear tag (Patriot)-Apply one tag to each ear of all animals older than 3 months. Do not use on lactating dairy cattle. Remove before slaughter.
- diazinon/chlorpyrifos ear tag (Warrior)-Apply one tag to each ear of all animals older than 3 months when flies appear. Do not use on lactating dairy cattle. Remove before slaughter.
- permethrin ear tag (GardStar Plus)-Apply one tag per ear on all animals when flies first appear in spring. Remove before slaughter.
- zetacypermethrin/piperonyl butoxide ear tag (PYthon MagnuM)-Apply one tag per head of all animals at least 3 months old when flies appear in spring. Remove tag at the end of fly season or before slaughter.
- dichlorvos spray (Prozap Beef & Dairy RTU) Apply 1 to 2 oz per adult animal as a mist to wet hair. Use proportionately lower rates for smaller animals. Do not exceed 2 oz per animal per day. Do not soak skin or wet hide.
- dichlorvos/piperonyl butoxide/pyrethrins (Prozap VIP Insect Spray, Super II Dairy & Farm Spray)-Apply 1 to 2 oz to each animal, proportional to size. Do not soak the skin or wet the hide. Do not apply more than once per day. Do not apply to animals less than 6 months of age.
- diflubenzuron/permethrin pour-on (Lice-Ban)-Apply 3 mL per 100 lb body weight to maximum of 30 mL.
- octanoic acid/nonanoic acid/decanoic acid (Ecovet Fly Repellent)-Apply to hair coat with small sprayer or a cloth. (Not registered in Oregon.)
- permethrin spray (Atroban 11% EC)-Dilute 1 quart per 50 gal water. Spray 1 to 2 quart per animal. Treat once every 2 weeks as needed.
- permethrin RTU pour-on & spray (Gordon's)-Apply undiluted along back and down face at 0.5 to 2 fl oz per 100 lb to a maximum of 20 oz. Use as needed but no more than once every 2 weeks.
- permethrin spray (Prozap Screw Worm Ear Tick Aerosol; Durvet Screw Worm Aerosol)-Spray about 3 seconds on each side. Repeat treatment with flies are troublesome.
- permethrin spray (Durvet 10%; Prozap Insectrin X Concentrate)-Dilute 0.64 oz (normal infestation) or 1.28 oz (severe infestation) per gallon water (0.05%, 0.10%). Spray to thoroughly cover entire animal. Spray lactating cows only after milking is complete.
- permethrin spray (Gardstar 40% EC)-Dilute at 118 ml (4 fl oz) per 25 gal water (0.05% ai). Apply 1 to 2 quarts high pressure spray over body of animal. For low-pressure spray, apply at 118 ml (4 fl oz) to 2.5 gal water; spray to point of runoff.
- pyrethrins/piperonyl butoxide spray (EverGreen Pro 60-6)-Dilute at 2 to 3 fl oz/gal of water. Apply 1 quart per adult animal. Wet hair thoroughly. Repeat weekly as needed.
- pyrethrins spray (PyGanic Livestock & Poultry Insecticide)-Dilute at 9 to 14 oz per gal water. Apply 1 quart per adult animal to thoroughly wet hair. Repeat treatment each week as needed. Do not exceed 1 treatment per day. This organic product is OMRI listed.
- pyrethrins spray (Evergreen Pyrethrum Concentrate)-Dilute at 2.5 to 4 oz per gal water. Apply one quart per adult animal to wet hair thoroughly. Repeat treatment weekly as needed. This organic product is OMRI listed.
- pyrethrins/permethrin/piperonyl butoxide aerosol (Pystol Farm & Dairy Aerosol)-Thoroughly spray entire animal for 2-4 seconds from approximately 2 ft away as it is being released to pasture. Do not spray directly toward animal's face.
- pyrethrins/piperonyl butoxide spray (Vampyre Misting Concentrate)-Dilute at 4.3 fl oz per gal water (for 0.10% pyrethrins) or 22 fl oz per gal water (for 0.50% pyrethrins). Spray about 3 seconds on each side of animal.
- pyrethrins/piperonyl butoxide/N-octyl bicycloheptene dicarboximide spray (SSI-50)-Spray animal as it's being released to pasture. Spot treat withers, shoulders, and back where saliva accumulates.
- rosemary, peppermint oils spray (Essentria All Purpose)-Mix at 30 to 90 ml (1 to 3 oz) per gal mineral oil. Spray directly on animal in amounts to sufficiently cover. Apply at least 20 minutes before milking of after milking is complete.
- thyme oil/2-phenethyl propionate/rosemary oil spray (EcoVia EC)-Dilute 0.5 to 1.5 oz per gal mineral oil USP. Spray to cover thoroughly. Repeat as necessary. Apply at least 20 min before milking or after milking is complete.
- permethrin backrubber or self-oiler (Gardstar 40% EC)-Dilute at 118 ml (4 oz) per 10 gal mineral oil or diesel oil. Keep rubbing device charged. Results improve with forced daily use.
- permethrin backrubber or self-oiler (Gordon's)-Use undiluted. Recharge as needed.
- pyrethrins 1% dust (Evergreen Pyrethrum Dust)-Directly apply 2 oz to animal with shaker can or other device. Can be applied through dust bag placed in area where cattle congregate or pass through. This organic product is OMRI listed.
- zetacypermethrin/piperonyl butoxide dust (PYthon)-Directly apply 2 oz per animal. Make sure to apply dust to legs. Repeat as needed but not more than once every 3 days.
Feed supplements (prevent development of flies in the manure of treated cattle)
- diflubenzuron feed supplement (ClariFly 0.04%; ClariFly 0.67%; ClariFly 8%; JustiFly 0.67%; JustiFly 8%)- Mix into grain according to label to provide 0.1 mg ai/kg (4.55 mg/100 lb) body weight per day (follow table on label). Start feeding early in spring before flies appear and discontinue when cold weather limits fly activity.
- diflubenzuron for milk (elim-A-fly Add-Pack with ClariFly 0.16%; JustiFly 0.16% Milk Replacer Product)-Mix daily into milk/milk replacer according to label to provide 0.1 mg ai/kg (0.1 oz elim-A-fly/100 lb) body weight per day. Start feeding early in spring before flies appear and discontinue when cold weather limits fly activity.
- diflubenzuron salt supplement (JustiFly Fly-A-Salt)-Provide free choice with target consumption of 0.1 oz per 100 lb body weight per day. Feed from before flies appear until end of fly season.
- diflubenzuron mineral tub (Vitalix ClariFly Tub)-Provide free choice with targeted consumption of 1.6 oz per 100 lb of cow per day (~one tub per 15-25 head). Provide before flies appear until end of fly season.
- tetrachlorvinphos mineral block (Prairie Pride Rabon)- Feed free choice, 1 block for 10-15 head of cattle.
- tetrachlorvinphos feed supplement (Rabon 97.3; Rabon 7.76)-Include in diet or supplement at 70 mg per 100 lb body weight daily. See Mixing and Use Instructions for additional details.