Brand: VAPONA ® Concentrate Insecticide


FORMULATION: liquid concentrate for spraying animals or farm premises

ACTIVE INGREDIENT(S): Dichlorvos: 40.2% = 402 g/L

CHEMICAL CLASS of the active ingredient(s): Organophosphate


PARASITES CONTROLLED (spectrum of activity)


Beef & Dairy (incl. lactating) Cattle

  • Fine mist spray: Dilution: 1 gal. in 50 gal. OR 5 oz. in 2 gal. (1% Dilution). Apply 1 to 2 fl. oz. of diluted solution (do not exceed 2 oz.) per animal daily as a fine mist spray. Be sure to cover all parts of animal for best results. Do not apply in combination with other dermal organophosphate pesticides (e.g. trichlorfon). Brahman and Brahman cross cattle should not be treated as they may show hypersensitivity to organophosphates. Do not wet the hide. Do not apply to calves under 6 months of age. Dichlorvos concentration in final dilution: ~8000 ppm* = mg/L ~ 0.8 - 1% Active Ingredient.

For indoor and outdoor off-animal uses in livestock facilities read the product label

* ppm = parts per million


  • LD50 (acute oral) in rats: 78.5 mg/kg (according to MSDS)
  • LD50 (acute dermal) in rabbits: >300 mg/kg (according to MSDS)
  • Estimated hazard class according to the WHO: II, moderately hazardous.
  • RESTRICTED USE PESTICIDE in the USA: Due to acute oral, acute dermal, primary eye and primary dermal toxicity. For retail sale to and use only by Certified Applicators or persons under their direct supervision, and only for those uses covered by the Certified Applicator’s Certification.

Suspected poisoning? Read the article on dichlorvos = DDVP safety in this site.

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

  • Cattle Meat: USA 1 day
  • Milk for human consumption: USA NIL

WARNING !!!: Never use on humans, dogs or cats.

Dichlorvos and all organophosphates (e.g. coumaphos, diazinon, dichlorvos, phosmet, etc.) etc. are highly toxic to birds, fish and aquatic invertebrates. Do not apply directly to water, or to areas where surface water is present or to intertidal areas below the mean high water mark. Do not contaminate water when disposing of equipment wash-waters or rinsate.

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


Risk of resistance? YES. Resistance of houseflies and mosquitoes to organophosphates (incl. dichlorvos) is widespread in the USA and worldwide, and can be very high. Cases of resistance of horn flies to organophosphates have been reported in the USA and elsewhere, but resistance of these flies to organophosphates is usually weaker and less widespread than to synthetic pyrethroids (e.g. permethrin).

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: USA
GENERIC BRANDS available? YES, but rather few with dichlorvos in the USA. This brand containing generic dichlorvos is marketed by BAYER (now ELANCO) in the USA.

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

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


Dichlorvos (also called DDVP) is a veteran broad-spectrum organophosphate introduced in the 1960s that has been abundantly used worldwide in agriculture, hygiene and veterinary insecticides. It has the specific feature of being highly volatile. This makes it particularly appropriate for misting or fogging because it easily reaches flying insects (mosquitoes, flies, etc) and penetrates into cracks and crevices where many pests use to hide (e.g. cockroaches, beetles, etc.). Its volatility also favors fast penetration into the insect's body, which results in a rather quick knock-down effect. However, when applied directly to cattle, it quickly evaporates and consequently its residual effect is rather weak, i.e. protection against re-infestation is rather short, not longer than 2-3 days.

Control of susceptible (i.e. non-resistant) horn flies is usually good with sprayed organophosphates, because they spend a lot of time on cattle and thus are exposed to the insecticide for a long period of time. Control of face flies is often not as good, due to their different behavior: they do not spend a lot of time on the animals and visit mainly body parts in the face that are humid with body fluids (eyes, nostrils, around the mouth), where the insecticide concentration is diluted by these body fluids. Stable flies and mosquitoes may bite the treated animal anywhere in its body and remain attached and thus exposed to the insecticide only during their blood meals that last a few seconds or minutes, which is often too short to kill them. Trying to control housefly populations with on-animal topical products is usually ineffective. The simple reason is that they spend most of their time off-the animals.

Nowadays this product is one of the few products containing organophosphates left for spraying animals against external parasites (flies, liceticks, etc.). Liquid concentrates containing organophosphates were widely used between their discovery (~1950s) and the 1990s. But subsequently most of them have been withdrawn and replaced by concentrates with less toxic synthetic pyrethroids (e.g. permethrin) or by more convenient ready-to-use pour-ons (mainly with macrocyclic lactones such as ivermectin, or synthetic pyrethroids). Against horn flies organophosphates (mainly diazinon) are still widely used in insecticide-impregnated ear-tags.

Insecticide concentrates for spraying and dipping 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 1950s to 1970s) and many pests have developed resistance to them. More modern and more effective active ingredients for the control of external parasites are often not available as concentrates but only as ready-to-use pour-ons, injectables, 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 and often not approved for the control of as many pests as the concentrates.

All organophosphates are veteran pesticides developed in the 1950s-1960s 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, organophosphates 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 organophosphates 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.

For best results it is very important to ensure a complete coverage of the animals' hair coat. This is best achieved after dipping the animals. Best alternative to dipping is high pressure spraying (depending on size and hair coat, adult cattle need 3 to up to 10 liters product for complete wetting). Efficacy after hand spraying or spot application are often poor due to the fact that using these methods some parts of the body may not be properly treated (e.g. inside the ears, below the tail, the udders, etc.), which allows a significant number of parasites to survive, reproduce and perpetuate the infestations. To learn more about spraying cattle and other livestock click here.


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.