Brand: NUCIDOL ® 200 EC

Company: ZAGRO

FORMULATION: liquid concentrate for spraying and backrubbers.

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

CHEMICAL CLASS of the active ingredient(s): Organophosphate


PARASITES CONTROLLED (spectrum of activity)

  • Cattle: Lice (Bovicola bovis, Linognathus vituli, Haematopinus eurysternus) and buffalo flies (Haematobia irritans exigua)
  • Goats: Lice (Bovicola caprae)
  • Pig: Lice (Haematopinus suis) and mange mites (Sarcoptes spp)
  • Sheep: dressing against blowfly strike (Lucilia cuprina) on struck sheep.
  • Sheds: Houseflies (Musca domestica) and stable flies (Stomoxys calcictrans)

RECOMMENDED DOSE & Use instructions

Animal / Situation

Pest Rate Critical Comments

High Volume Other Application

Lice (Bovicola bovis, Linognathus vituli)  250 mL product per 100 L water = 500 ppm* = mg/L   Applay at least 4.5 litres of spray per beast using hand spraying or high volume cattle spray units. Ensure animal is thoroughly covered. Respray as necessary.
  Low volume cattle sprayer: 500 mL product per 100 L water = = 1'000 ppm* = mg/L Applay at least 2.3 litres of spray per beast using low volume cattle sprayer. Examine cattle after 17 days for newly hatched lice and later during the
season for further lice activity. Respray
as necessary.
Buffalo Flies (Haematobia irritans exigua)   400 mL product per 100 L water = 800 ppm* = mg/L    Apply 500 mL per beast and spray along
backline. Respray as necessary.
  Backrubber: 500 mL product per 10 L of oil = 10'000 ppm* = mg/L Soak backrubber thoroughly. Repeat
treatment in 14 days.
  Rubbing post: 500 mL product per 10 L of oil = 10'000 ppm* = mg/L Fill post. Replenish as necessary.
Pigs  Lice (Haematopinus suis) 250 mL product per 100 L water = 500 ppm* = mg/L     Spray pigs and sties thoroughly.
Repeat treatment in 14 days. 
Mange mites (Sarcoptes spp) Spray pigs and sties thoroughly. Repeat
treatment twice with 10 day intervals
between treatments. 
Goats Biting and Sucking Lice (Damalinia caprae; Linognathus stenopsis 250 mL product per 100 L water = 500 ppm* = mg/L   Spray goats thoroughly making sure hair
is wet to the skin. Examine goats after
14 days for newly hatched lice and
later during the season for further lice
activity. Respray as necessary. 
Horses Flies (Musca vetustissima) and Lice (Damalinia equi; Haematopinus asini) 25 mL product per 100 L water = 5'000 ppm* = mg/L Swab: 25 mL product per 100 L water = 5'000 ppm* = mg/L Spray or swab liberally as required. 
Animal Sheds Flies: Houseflies (Musca domestica) and stable flies (Stomoxys calcictrans) 250 mL product per 100 L water = 500 ppm* = mg/L   Spray the inner walls thoroughly and
any other places where flies settle.
Respray as necessary. 

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


  • LD50 (acute oral) in rats: for the a.i. 300-400 mg/kg
  • LD50 (acute dermal) in rats: for the a.i. 360 mg/kg
    • Estimated hazard class according to the WHO: III, slightly hazardous.

Suspected poisoning? Read the article on diazinon = dimpylate safety in this site.

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

  • Meat:
    • Cattle, horses: AUS 3 days
    • Goats, pigs: AUS 14 days (ESI 21 DAYS
  • Milk for human consumption: AUS DO NOT USE on lactating or pregnant animals where milk or milk products may be used for human consumption.
  • ESI: This product does not have an ESI established

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

Diazinon and all organophosphates (e.g. chlorfenvinphos, ethion, etc.) etc. are highly toxic to birds, fish and aquatic invertebrates.

Organophosphates dips are submitted to strict operator safety precautions and dip wash disposal regulations. Read the product label carefully and ensure strict accomplishment of all safety instructions.

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 organophosphates has been reported for buffalo flies in Australia and for horn flies (their close relatives) in the USA and elsewhere. But resistance to organophosphates is usually weaker and less widespread than resistance to synthetic pyrethroids. Resistance of houseflies to organophosphates and most other chemical classes is widespread worldwide, including Australia.

This means that if this product does not achieve the expected efficacy against the mentioned parasites, it is probably due to incorrect use rather than to a resistance problem. Incorrect use is usually the most frequent cause of product failure.

So far there are no reports on resistance of cattle lice, pig lice, and pig mange mites to diazinon

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. This brand contains itself generic diazinon and is marketed by ZAGRO (a company from Singapur), in Australia through a local distributor.

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

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


Diazinon (also called dimpylate) is a veteran broad-spectrum organophosphate that has been very abundantly used worldwide in agriculture, hygiene and veterinary insecticides. In sheep, diazinon was particularly appreciated for the control and prevention of sheep scab mites, blowfly strike and lice. It has a high affinity for wool lipids, where it dissolves after topical treatment and remains for a long period of time ensuring several weeks and even months protection against re-infestation.

Usage of diazinon products in sheep strongly declined after several countries imposed very strict safety precautions and dip wash disposal regulations (e.g. the UK & Australia) for all dips in the late 1990s. As a consequence, using these products became rather inconvenient and often also expensive. Soon after, NOVARTIS, the market leader for diazinon products for sheep, divested all its organophosphates for strategic reasons, including its diazinon sheep brands (NEOCIDOL, TOPCLIP).

Nowadays, in many countries sprays and dips containing diazinon, other organophosphates and even >synthetic pyrethroids have been vastly replaced by injectable macrocyclic lactones (e.g. doramectinivermectin, moxidectin, etc.) that have become affordable, are much more convenient than sprays and dips, and as effective. Diazinon is still abundantly used worldwide in insecticide-impregnated ear-tags for fly control on cattle.

For best results against lice and mites it is very important to ensure a complete coverage of the animals' hair coat. Depending on size and hair coat, adult cattle need 3 to up to 10 liters dilution per head for complete wetting, swine need about 1 liter. Lice and mites spend their whole life on the infected animals but are likely to survive hidden inside the ears if they are not properly treated. And their eggs remain unaffected by the insecticide: this is why it is very important to re-treat the animals after 1-3 weeks, when most of the eggs laid before the previous treatment have already hatched. Otherwise a significant number of parasites will survive, reproduce and perpetuate the infestations. To learn more about spraying cattle and other livestock click here.

Backrubbers and rubbing posts used mainly against biting flies on cattle have and inherent weakness: Dosing depends on the behavior of the animals. It is unavoidable that some animals get too much product, and other animals not enough. Besides insufficient protection of some animals, this may cause excessive residues in other animals. For these reasons self application devices are no more allowed in many countries (e.g. the EU). And it is generally accepted that underdosing of animals favors resistance development. To learn more about backrubbers for cattle click here.

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 parsite 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.


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.