What kind of eradication treatments have been conducted against the gypsy moth?
1. Mechanical methods include egg mass scraping and the use of tree bands as a barrier that excludes larvae from trees or as a harborage area to aggregate, collect, and destroy larvae.
2. Cultural practices are achieved through education and outreach to, or regulation of, affected communities and stakeholders. The goal of this strategy is to elicit behavioral change that assists eradication. Restricting movement of gypsy moth out of infested areas or into non-infested areas is key for successful eradication and can be achieved with education or regulation, usually in the form of quarantines.
3. Biological control makes use of naturally occurring organisms like bacteria, viruses, predators, and parasites or insect behavior to impact unwanted pests like gypsy moth.
Examples of biological control used for gypsy moth eradication include:
- Sterile insect technique: This technique consists of an aerial release of a large number of sterile male gypsy moths; reducing the chance that female moths will mate with fertile males. The result is progressively fewer and fewer fertile egg masses being produced, and eventual elimination of the population.
- Gypsy moth virus (Gypcheck®). This is a nucleopolyhedrosis virus which occurs naturally and is specific to gypsy moth. Gypcheck® is a product made from the gypsy moth nucleopolyhedrosis virus.
- Bacillus thuringiensis var. kurstaki (Btk). This is a naturally occurring soil bacteria. Formulations of this bacteria are effective against caterpillars of many species of Lepidoptera (moths and butterflies) including gypsy moth.
- Predators and parasites are only occasionally used in eradication efforts. They are most often employed to reduce the size of an established population or maintain a population at a low level. Dozens of different predators and parasites of gypsy moth have been released in North America.
4. Chemical control options have been used in many parts of the country since gypsy moth was introduced.
Examples of chemical control options include:
- Mass trapping: This treatment technique consists of deploying large numbers of traps baited with synthetic gypsy moth sex pheromone used to attract the male gypsy moth and prevent them from mating with females, thereby causing a population reduction.
- Mating disruption: This treatment technique consists of applying tiny plastic flakes or beads containing a synthetic gypsy moth sex pheromone. The pheromone confuses male gypsy moths and prevents them from locating and mating with females.
- Insecticide application: Ground and aerial application of insecticide has been used to support gypsy moth eradication. Chemical insecticides include Diflubenzuron (Dimilin®) and Tebufenozide (Mimic®). These are insect growth regulators that disrupt the ability of insect larvae that produce an external skeleton, containing chitin, to molt from one stage to another.
Which treatments has WSDA used the most?
When reproducing populations of gypsy moth have been identified in Washington State, the most commonly used technique has been application of the biological insecticide Btk targeting the second larval stage of the gypsy moth. Delivery methods have included ground spraying and aerial application using helicopters or fixed wing aircraft.
Does Btk have any disadvantages?
I have read several accounts on the Internet of people suffering adverse health effects after Btk treatments. Just how safe is the insecticide?
What common sense precautions do public health officials recommend people take after Btk treatments?
Why won’t WSDA release the inert ingredients of Btk?
What are the advantages and disadvantages of the other eradication methods?
- Advantage: Target specific, and pinpoints center of population.
- Disadvantage: Not a proven eradication method.
- Advantage: Target specific.
- Disadvantages: Not a proven eradication method; effectiveness cannot be evaluated as trapping treatment areas is not possible; and effective adjuvant for mating disruption not registered in Washington State.
- Advantage: Target specific; minimal impact on environment.
- Disadvantage: Very expensive, requires mass rearing, requires repeated treatments over a span of yeras.
- Advantage: Target specific.
- Disadvantage: Not a proven eradication method; most effective with high populations, not low populations.
- Advantage: Proven eradication method.
- Disadvantages: Product has a long residual, remaining in environment for long period; and toxic to many non- target insects.
What can I do if I oppose the application of Btk?
Will Btk harm bees? What about birds, fish, and other aquatic life?
What about other moths and butterflies? What about the monarch butterfly?
Monarch butterflies are not likely be impacted in Washington from Btk treatments. First, Washington - especially Western Washington - is not a primary migration area for the monarch butterfly due to rarity of suitable host material (milkweeds) and unfavorable climate conditions for this species. Second, even if monarch butterflies arrive in Washington, the have a much different life cycle than the gypsy moth. Caterpillars only begin feeding in late June in Washington, after any Btk applications have degraded. Read more on our Monarch and the Moth blog.
Is Btk or Foray 48B genetically modified or does it contain GMOs?
Will Foray 48B cause damage to car finishes?
If the automobile’s paint is old, oxidized, and/or severely weathered, Foray will adhere to this porous surface; it will be more difficult to remove. A large bath towel may be soaked and placed upon the painted surfaces for several minutes to allow the Foray deposits to become rehydrated. This will make the spray deposit easier to remove. In extreme cases, several soakings with a wet towel may be required.