Diflubenzuron is an antiparasitic active ingredient used in veterinary medicine in livestock and horses against a few external parasites (fleas, flies, etc.). It is also used against agricultural and household pests. It is a so-called Insect Growth Regulator (IGR) belonging to the chemical class of the benzoylphenyl ureas.


Type: pesticide
Chemical class: bezoylurea, insect development inhibitor


Molecular structure of DIFLUBENZURON






Type of action: contact and oral larvicide
Main veterinary parasites controlled: larvae (maggots) of houseflies, blowflieshorn flies, mosquitoes, fleas, lice, etc.

Efficacy against a specific parasite depends on the delivery form and on the dose administered.

Click here for general information on features and characteristics of PARASITICIDES.


Diflubenzuron is a broad-spectrum insect development inhibitor (= insect growth regulator, IGR) that blocks development of all kinds of insects in livestock manure (also beneficials) and in sheep wool (e.g. lice). It is ineffective against mites and ticks or any parasitic worms.

It is used moderately for topical treatment (mainly pour-on) of sheep and cattle against lice in a few countries (e.g. Australia; in New Zealand also as a preventative of blowfly strike in sheep).

It is used as well as a feed-through larvicide (feed additives) in cattle and horses against several fly species (houseflieshorn flies, stable flies, face flies, etc.) in a few countries.

It is also moderately used for off-animal treatment of livestock facilities against any kind of flies. It is not used in pets.

The table below indicates some usual dosing recommendations for diflubenzuron issued by manufacturers or documented in the scientific literature. They may not be approved in some countries.

Dosing recommendations for DIFLUBENZURON
Delivery Parasites Dose (against diflubenzuron-susceptible parasites)
Feed-thru Fly larvae 0.1 mg/kg daily in feed during the fly season
Pour-on Lice 3-8 mg/kg, dep. on animals weight
Pour-on Lice 7-20 mg/kg, dep. on animal's weight
Feed-thru Houseflies & stable flies 6.8 mg/100 pounds = 15 mg/100 kg daily in feed during the fly season.

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Dosing recommendations for antiparasitics depend on national regulations. National regulatory authorities determine whether a product is approved for a given indication, i.e. use on a particular host at a specific dose and against a specific parasiteCheck the labels of the products available in your country for specific information on approved indications.

In most finished products, efficacy and safety depend not only on the amount of active ingredient(s) but also on their formulations (i.e. the type and amount of so-called inert ingredients), particularly in pour-ons. These inert ingredients can significantly affect the pharmacokinetic behavior (e.g. absorption through the skin, distribution within the body, spreading throughout the body surface, etc). Generic products usually contain the same amount of active ingredient(s) as the original product, but often in quite different formulations. In many cases, the curative (therapeutic) efficacy of the different formulations is quite comparable, but the protective (prophylactic) efficacy that determines the length of protection against re-infestations may be rather different.


Oral LD50, rat, acute*:  >4640 mg/kg
Dermal LD50, rat, acute*: >2000 mg/kg
* These values refer to the active ingredient. Toxicity has to be determined for each formulation as well. Formulations are usually significantly less toxic than the active ingredients.

MRL (maximum residue limit) set for animal tissues (either beef, mutton pork or chicken)*:

  • CODEX: Yes
  • EU: Yes
  • USA: Yes
  • AUS: Yes

* This information is an indicator of the acceptance of an active ingredient by the most influential regulatory bodies for use on livestock. MRL's for animal tissues may be set also for agricultural pesticides that are not approved for use on animals but are used on commodities fed to animals. A MRL may be also set in the form of an IMPORT TOLERANCE for active ingredients not approved in a particular country but approved for imported animal commodities.

Withholding periods for meat, milk, eggs, etc. depend on delivery form, dose and national regulations. Check the product label in your country.

General safety information for antiparasitics is available in specific articles in this site (click to visit):


Never use agricultural or hygiene products with this or any other active ingredient on livestock or pets, even if there are veterinary products with this same active ingredient approved for use on animals. The formulations for agricultural or hygiene use are different and may be toxic for livestock or pets.

It is obvious that veterinary products are not intended for and should never be used on humans!!!


Decade of introduction: 1970
Introduced by: PHILIPS-DUPHAR
Some original brands: DIMILIN, VIGILANTE-BOLUS
Patent: Expired (particular formulations may be still patent-protected)

Use in LIVESTOCK: Yes, moderate
Use in HORSES: Yes, scarce
Use in

Main delivery forms

Use in human medicine: No
Use in
public/domestic hygiene: Yes
Use in
agriculture: Yes
Generics available: 
Yes, a few


In livestock: Yes: in houseflies (Musca domestica), sheep lice (Damalinia=Bovicola ovis) and blowflies (Lucilia spp)


Diflubenzuron is the first benzoylurea and one of the first insect development inhibitors discovered and introduced in the Animal Health market in the 1970's.

It is a broad-spectrum insect larvicide, highly effective against larvae (maggots) of houseflies, blowflies, mosquitoes, fleas, lice, etc. but ineffective against larvae of ticks or mites.

It is moderately used in livestock, mainly in sheep against sheep lice (Damalinia=Bovicola ovis) and blowfly strike, as in cattle against horn flies. It is also used  for premise, manure and environmental treatment in livestock operations for controlling houseflies and other nuisance flies.

It is not used in dogs or cats.

Pharmacokinetics of diflubenzuron

Topically administered diblubenzuron is poorly absorbed through the skin. After oral administration to cattle and pig about 70% to 85% of the administered dose is excreted unchanged in the feces, and about 5% in urine. In sheep, excretion through urine and feces is equally distributed.

Mechanism of action of diflubenzuron

Benzoylureas, as other Chitin Synthesis Inhibitors hamper the synthesis and/or the correct deposit of chitin in the cuticle of insects . As a consequence larvae or nymphs cannot properly molt and die during the molting process. Egg hatching is also interrupted due to the fact that young larvae developing inside the egg have to molt before hatching. If the adult female was treated with a chitin synthesis inhibitor significant amounts of it are passed to the eggs. The embryo can develop quite normally but it dies during the first molt, still inside the eggshell.

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