The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Diflubenzuron (CAS 35367-38-5)
- Chemical class
- Benzoylurea; IRAC Group 15 inhibitors of chitin biosynthesis.[2]
- Mode of action
- IRAC Group 15: Inhibitors of chitin biosynthesis affecting CHS1: benzoylureas[2]
- Signal word
- Dimilin 2L: Caution[1]
How a growth regulator kills
Group 15 benzoylureas block chitin, the material insects need to build a new exoskeleton, so larvae die when they try to molt, which is why results take days.[1][2]
Where it is used
Because it works on molting larvae, timing matters: the label directs applications at the first sign of larval infestation.[1]
Its specificity makes it a fit for integrated pest management programs, according to the label.[1]
Rotate with other insecticide groups within and between seasons to slow resistance.[1]
Uses include tree fruit, field crops, rangeland grasshoppers and Mormon crickets, and USDA spongy (gypsy) moth programs.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Dimilin 2L[1] | UPL NA Inc. | 400-461 | 22.0% | flowable concentrate (restricted use) | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Dimilin 2L | Peaches, nectarines, plums and other stone fruit (one of many labeled crops) | Peach twig borer, fall webworm, filbert and obliquebanded leafrollers, omnivorous leafroller, oriental fruit moth | 8–16 fl oz product per acre[1] 12 to 16 fl oz per acre for peach twig borer and 8 to 16 fl oz for fall webworm and leafrollers; up to two applications 14 days apart. Use the higher rate where infestations have been heavy. |
Safety and environmental hazards
People
Signal word CAUTION. Handlers wear long sleeves, long pants, chemical-resistant gloves, shoes and socks.[1]
Pets
It is a restricted use product for certified applicators; it isn't sold for home use.[1]
Bees and pollinators
Bees can be exposed through direct contact, residues on plants, and nectar and pollen; drift onto hives or pollinator habitat can reduce the viability of immature bees, so applicators minimize drift and exposure.[1]
Fish and water
Restricted use because of toxicity to aquatic invertebrates. It can run off for several months or more after application, so applicators avoid spraying when rain is forecast within 48 hours and keep vegetated buffer strips next to water.[1]
Common questions
- Why is Dimilin 2L a restricted use pesticide?
- Because of its toxicity to aquatic invertebrate animals; it is sold to and used only by certified applicators or people under their direct supervision.[1]
- How fast does diflubenzuron work?
- Slowly. It disrupts molting, so several days may pass before the full effect is seen.[1]
- Does diflubenzuron kill adult insects?
- It targets larvae that are molting; the label describes it as disrupting the normal molting process of insect larvae.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Dimilin 2L label, EPA Reg. No. 400-461 (EPA-stamped, Nov. 2, 2020).” www3.epa.gov/pesticides/chem_search/ppls/000400-00461-20201102.pdf (accessed 2026-10-06)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-10-06)