Understanding Insect Growth Regulators (IGRs)

What are Insect Growth Regulators
Insect growth regulators are a feed-through, preventive that target flies that develop in manure. IGR’s are non-traditional insecticides that target the juvenile life-stage and interrupt or inhibit the life cycle of harmful pests; in this case, flies that develop in manure.

IGR’s are designed to prevent the development of new flies by interrupting the molting stage. IGRs do not kill adult flies.

IGRs are a feed-through product, meaning that they only pass through the digestive tract of cattle, horses, goats, and pigs and are not digested or absorbed by the animal.


Why Use Insect Growth Regulator
No need to process, gather and work your livestock! IGR’s allow you to provide fly control right in your feed or minerals.


When to Use Insect Growth Regulators
Incorporating IGR into your pest control program 30 days prior to the last frost is the standard recommendation. If IGR is started later in the fly season, a knock down spray to kill adult flies will need to be incorporated.


How to Administer Insect Growth Regulators
Because IGRs are a feed-through product, they are incorporated into your feed or minerals. IGRs are available in a variety of formulations:

  • Liquid Loomix
  • Protein Tubs
  • Loose Mineral
  • Pellets – which can be feed separately or top dressed into a ration
  • Premixed Feed & Supplement


Don’t get discouraged
Keep in mind that IGR’s treat the manure only when they are actively being fed.  If there are other manure sources nearby, like your neighbor – the dairy, an IGR may not be the solution for you. Likewise, if there is manure in your pens or pastures that does not contain IGR, the flies can lay their eggs in that and develop into adults normally.

It can take up to four weeks to realize a significant reduction in fly numbers when using a feed-through IGR. Because flies can breed and develop in areas aside from manure, other fly control measures should be implemented to provide a well-rounded pest control program.

We’re here to help you create, implement, and maintain an effective fly control program. Stop by either store to visit with our staff and get the right products for your operation.



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