Brand: SUMIFLY ® Buffalo Fly Insecticide

Company: ZOETIS

FORMULATION: liquid concentrate for spraying.

ACTIVE INGREDIENT(S): Fenvalerate: 20% = 200 g/L

CHEMICAL CLASS of the active ingredient(s): Synthetic pyrethroids


PARASITES CONTROLLED (spectrum of activity)

  • Cattle: Buffalo flies (Haematobia irritans exigua)
  • Horses: Queensland itch (Culicoides brevitarsus)

RECOMMENDED DOSE & Use instructions

Recommended dilution rate: 1:200 = 1 L product in 200 L water (or 50 mL product in 10 L water, or 5 mL product in 1 L water), equivalent to 1000 mg/L = ppm (parts per million). Add the required quantity of product to water in a bucket and mix thoroughly. Sumifly can be mixed with hard or soft water.

  • Buffalo fly: Apply when buffalo fly are causing irritation to animals.
    • Cattle, horses: Add 50 mL product to 10 L of water and mix. With the aid of a stirrup pump or similar sprayer apply 200 mL of the diluted wash along the backline of each animal.
    • Calves, foals, young cattle, young horses: Apply proportionately less wash according to size (10 mL/15 kg).
  • Queensland itch: Apply at 7 day intervals until the symptoms of Queensland itch disappear.
    • Horses. Add 5 mL product to 1 L of water and mix. Apply between 800 mL and 1 L of the diluted wash to the backline and other affected areas using a stirrup pump or similar sprayer. Alternatively apply by sponging, wearing PVC or rubber gloves while applying.

Read the complete product label carefully and ensure thorough accomplishment of all the use instructions.


  • LD50 (acute oral) in rats: for the a.i. 451 mg/kg
  • LD50 (acute dermal) in rats: for the a.i. > 5000 mg/kg
    • Estimated hazard class according to the WHO: III, slightly hazardous.

Withholding periods (=withdrawal times) in days for meat & milk (country-specific differences may apply: read the product label)

  • Meat: AUS NIL (0 days)
    Milk for human consumption: AUS NIL (0 days)
  • ESI: NIL (0 days)

WARNING !!!: Never use on humans or cats. Synthetic pyrethroids are toxic to cats!

Fenvalerate, and all synthetic pyrethroids (e.g. cyhalothrin, cypermethrin, deltamethrin, flumethrin, etc.) are extremely toxic to fish and aquatic invertebrates. Do not contaminate dams, streams or waterways with product or used containers. Store original container, tightly closed in a safe place under lock and key.

WARNING !!!: Never use on humanscats or poultry.

You may be interested in the following articles in this site dealing with the general safety of veterinary products:


Risk of resistance? YES. Resistance to synthetic pyrethroids (incl. fenvalerate) has been reported for buffalo flies in Australia and for horn flies (their close relatives) in the USA and elsewhere. Resistance of buffalo flies can be very high.

This means that if this product does not achieve the expected efficacy against the mentioned parasites, it may be due to resistance and not to incorrect use, which is usually the most frequent cause of product failure.

Alternative chemical classes/active ingredients to prevent resistance of external parasites through product rotation:

These alternative products may not be available in all countries, or may not be available for spraying, or may not be effective against all the concerned parasites.

Learn more about resistance and how it develops.


Are the active ingredients of this product ORIGINAL* or GENERICS**?


*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.

COUNTRIES where this brand/product is marketed: Australia
GENERIC BRANDS available? YES, with fenvalerate or with comparable synthetic pyrethroids. This brand with fenvalerate is marketed in Australia by ZOETIS.

Click here to learn more about GENERIC vs. ORIGINAL drugs.

For an overview on the most used antiparasitic spray, dip & dust BRANDS click here.


This product is one of the numerous liquid insecticides for spraying animals containing synthetic pyrethroids for the control of flies. Worldwide there are hundreds if not thousands of such products. Besides fenvalerate, numerous other synthetic pyrethroids are used worldwide in such products, e.g. cyhalothrin, cypermethrin, deltamethrin, flumethrin, fenvaleratepermethrin, etc. They all have a similar spectrum of activity and a comparable safety profile.

Fenvalerate and permethrin belong to the so-called third generation of synthetic pyrethroids in the late 1970s. Fenvalerate was introduced by SUMITOMO. Compared with the previous generations, these compounds are not photosensitive, i.e. they are not broken down by sunlight. This made them suitable for being used on crops and livestock. Nowadays fenvalerate is moderately used in agriculture and rather scarcely on livestock.

Control of susceptible (i.e. non-resistant) buffalo flies is usually excellent, because they spend a lot of time on cattle and thus are exposed to the insecticide for a long period of time. But as already mentioned, buffalo flies have developed high resistance to all synthetic pyrethroids in many places. Resistance can be that high, that this product and comparable ones with synthetic pyrethroids become completely useless against buffalo flies.

Insecticide concentrates for spraying such as this product often represent the cheapest option for insect control on animals. However the active ingredients used in such products are mostly rather old (introduced in the 1970s - 1980s) and many pests have developed resistance to them. More modern and more effective active ingredients for the control of biting flies are often not available as concentrates but only as ready-to-use pour-ons or in the form of insecticide-impregnated ear-tags. They are usually more effective, more convenient and with a longer protection period than the concentrates, but are also more expensive.

Fenvalerate and all synthetic pyrethroids are veteran pesticides developed in the 1970s - 1980s and are basically contact insecticides. This means that when the parasite comes in contact with it (e.g. during the blood meal, after landing on a treated host, etc), the active ingredient that impregnates the host's hair coat penetrates through the cuticle (i.e. the "skin" of insects and other arthropods) into its organism and disturbs essential biological processes in the parasite's body, in this case its nervous system.

After administration to livestock or other animals, synthetic pyrethroids do not have a systemic mode of action, i.e. they are not transmitted to the parasite through the blood or the host. Topically administered synthetic pyrethroids are very poorly absorbed through the skin of the hosts, and what is absorbed is quickly broken down and/or excreted. Consequently the concentration reached in the blood is too low to kill blood-sucking parasites. But this is why they are considered rather safe for mammals, both humans and livestock (cats are an exception: pyrethroids are toxic to them!) and why they leave rather low residues in meat.

All synthetic pyrethroids have a certain repellent effect, mainly on mosquitoes. The repellent effect on flies is mostly weaker than on mosquitoes.

It is useful to know that the active ingredients of many synthetic pyrethroids consist in a mixture of various optical isomersFenvalerate is a mixture of 4 optical isomers, which show different insecticidal activity but also different toxicity. The 2-S alpha (or SS) isomer is particularly effective and is known as Esfenvalerate. Fenvalerate contains ~23% of this isomer.


This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics. 

Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.

In case of doubt contact the manufacturer or a veterinary professional.