Product Description

An insecticide containing 1% permethrin and 1% piperonyl butoxide. Controls lice, horn flies and face flies on lactating and non-lactating dairy cattle, beef cattle and calves and aids in control of horse flies, stable flies, house flies, mosquitoes and black flies as well as others.


Synergized Delice formula controls wide range of insects on livestock and premises.

  • Migrates over animal’s skin and hair coat for maximum coverage.
  • Use on cattle of all ages.
  • Convenient application methods:
    • Pour-on animal
    • Spray-on animal
    • Spray-on premise
    • Diluted for back rubbers
  • Oil based for application anytime of year.


READY TO USE – No dilution necessary.
Do not apply to lactating or dry dairy cows.
Do not apply this product to face of beef cattle or calves.

Except when applying to livestock:

  • Do not apply this product in a way that will contact adults, children, or pets, either directly or through drift.
  • Only protected handlers may be in the area during application.
  • Do not enter or allow others to enter treated area until sprays have dried.
  • Do not enter or allow others to enter treated area until vapors, mists, and aerosols have dispersed, and the treated area has been thoroughly ventilated.

When used in dairy barns or facilities: Close milk bulk tank lids to prevent contamination from spray and from dead or falling insects. Remove or cover milking utensils before application. Wash teats of treated animals before milking.

Not for use in outdoor residential misting systems (indoor or outdoor). Not for use in metered release systems.

Apply ToTarget InsectsApplication Instructions
Lactating and Non-Lactating Dairy Cattle, Beef Cattle and CalvesLice, Horn flies, face flies. Aids in Control of Horse flies, Stable flies, Mosquitoes, and Black fliesDosage: Apply 1/2 fl oz (15 cc) per 100 lbs body wt of animal up to a maximum of 5 fl oz for any one animal. 
Pour-On: Pour correct dose along back and down face. 
Ready to Use Sprayer: Use undiluted in a mist sprayer to apply correct dose. Apply directly to neck, face, back, legs, and ears. 
Back Rubber Use: Mix 1 pint per gallon #2 diesel or mineral oil. Keep rubbing device charged. Results improved by daily forced use.
SheepSheep keds, LicePour along back. Apply 1/4 fl oz (7.5 cc) per 50 lbs body wt of animal, up to a maximum of 3 fl oz for any one animal. For optimum control, all animals in the flock should be treated after shearing.
Premises – In and around Horse, Beef, Dairy, Swine, Sheep, and Poultry premises. Animal Hospital Pens and Kennels and outside Meat Processing Premises.House flies, Stable flies, Face flies, Gnats, Mosquitoes, Black Flies, Fleas, Little House flies (Fannia spp). Aids in control of cockroaches, ants, spiders, cricketsFor use as a ready-to-use spot spray or premise spray, use undiluted in a mist sprayer. Apply directly to surface to leave a residual insecticidal coating, paying particular attention to areas where insects crawl or alight. One gallon will treat approximately 7,300 square feet.

For cattle and sheep, repeat treatment as needed, but not more than once every two weeks. For optimum lice control, two treatments at a 14-day interval are recommended. 

Special Note

SYNERGIZED DELICE Insecticide is not effective in controlling cattle grubs. SYNERGIZED DELICE Insecticide is an oil-base, ready-to-use product, that may leave an oily appearance on the hair coat of some animals. SYNERGIZED DELICE Insecticide should be used in an integrated pest management system which may involve repeat treatments and the use of other pest control practices.

Active Ingredients

Permethrin 1%*
Piperonyl butoxide 1%**


One U.S. Gallon (3.785 L) treats 46 550 lb Cattle.



First Aid


  • Take off contaminated clothing.
  • Rinse skin immediately with plenty of water for 15-20 minutes.
  • Call a poison control center or doctor for treatment advice.


  • Call a poison control center or doctor immediately for treatment advice.
  • Do not induce vomiting unless told to do so by the poison control center or doctor.
  • Do not give any liquid to the person.
  • Do not give anything by mouth to an unconscious person.


  • Move person to fresh air.
  • If person is not breathing, call 911 or an ambulance, then give artificial respiration, preferably mouth-to-mouth if possible.
  • Call a poison control center or doctor for further treatment advice.


  • Hold eye open and rinse slowly any gently with water for 15-20 minutes.
  • Remove contact lenses, if present, after the first 5 minutes, then continue rinsing eye.
  • Call a poison control center or doctor for treatment advice.

Note to Physician: Contains petroleum distillates. Vomiting may cause aspiration pneumonia.

Precautionary Statement


CAUTION: Harmful if absorbed through skin. Avoid contact with skin, eyes, and clothing. Prolonged or frequently repeated skin contact may cause allergic reaction in some individuals. Wash thoroughly with soap and water after handling.

PERSONAL PROTECTIVE EQUIPMENT (PPE): All handlers must wear: Long-sleeve shirt, long pants, shoes plus socks, and chemical-resistant gloves (barrier laminate, nitrile rubber, neoprene rubber or Viton).

Follow manufacturer’s instructions for cleaning/maintaining PPE. If no such instructions for washables exist, use detergent and hot water. Keep and wash PPE separately from other laundry. Discard clothing and other absorbent materials that have been drenched or heavily contaminated with this product’s concentrate. Do not reuse them.

User should wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet. Users should remove clothing/PPE immediately if pesticide gets inside. Then wash thoroughly and put on clean clothing. User should remove PPE immediately after handling this product. Wash the outside of gloves before removing. As soon as possible, wash thoroughly and change into clean clothing.

Environmental Hazards:

This pesticide is extremely toxic to aquatic organisms, including fish and invertebrates. To protect the environment do not allow pesticide to enter or run off into storm drains, drainage ditches, gutters, or surface waters. Applying this product in calm weather when rain is not predicted for the next 24 hours will help to ensure that wind or rain does not blow or wash pesticide off the treatment area.

This pesticide is highly toxic to bees exposed to direct treatment on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds while bees are actively visiting the treatment area.

Physical Or Chemical Hazards:

Do not use or store near heat or open flame.

Storage And Disposal

Do not contaminate water, food, or feed by storage or disposal.

STORAGE: Store in a cool, dry place. 

PESTICIDE DISPOSAL: Wastes resulting from the use of this product may be disposed of on site or at an approved waste disposal facility. 

CONTAINER HANDLING: Nonrefillable container. Do not reuse or refill this container. Triple rinse (or equivalent). Then offer for recycling or reconditioning, or puncture and dispose of in a sanitary landfill, or by incineration, or if allowed by State and local authorities, by burning. If burned, stay out of smoke.


U.S. only: Merck Animal Health or call 1-800-211-3573
For more information regarding efficacy and safety data, go to
For additional information, please see the product label.


*cis/trans ratio: Min 35% (±) cis and max 65% (±) trans.
**(butylcarbityl)(6-propylpiperonyl) ether related compounds.

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