What are they and how do they work?
(Trichogramma Mimutum, Ooencyrtus Kuvanae, Cotesia melanoscelus, Compsilura Coccinnata??? --I could not find out what wasps Praxix uses)
These are small wasps that parasitize either the gypsy moth egg sac or the caterpillar or in some cases the
moth itself, resulting in the demise of the egg, the caterpillar, or the moth.
- My understanding of the process is that the wasps are released in three waves, in the spring, summer
and fall. Villagers will also be encouraged to band their trees with burlap and pick off the caterpillars daily
wearing rubber gloves or using forceps. In the fall the villagers will be encouraged to collect the egg masses,
using gloves and to place them in a plastic bag and kill them by either cooking for two minutes in the microwave
or coating with an equal mixture of vegetable oil and water.
- Habitats sampled included forest and woodlands, residential forest openings, parks or small wood lots within residential areas and residences in suburban areas. Parasitism was unusually low, < 1% but averaged 4.5%.(17)
- More than 40 insect parasites have been released in North America in an attempt to control gypsy moth biologically. Of these 10 are now permanently established in the US, but substantial scientific research has shown that none are capable of causing collapse of established outbreaks. Commercially available parasitic wasp have also been released in attempts to control gypsy moth, but there is no scientific evidence that these have any effect on gypsy moth populations. or even commonly parasitize gypsy moths. However Trichogramma spp. have been shown to parasitize a wide range of other butterfly and moth species.(3)
- The Ooencyrtus Kuvanae wasp parasitizes gypsy moth eggs, typically killing about 20% of the egg mass.(4)
- Three generations of this wasp may occur in the summer and fall after the egg masses are laid and another generation may occur the following spring.(9)
- Because it is small, it can usually attack only the eggs in the upper layer of a gypsy moth egg mass. In many years, however, it is able to kill 20-30 percent of the eggs in the egg mass.(9)
- The Cotesia Melanoscelus, will attack the moth itself. However the small wasp sometimes have difficulty attacking larger gypsy moth caterpillars and the wasps has its own natural enemies that may limit its effectiveness.(10)
- The Compsilura Coccinnata fly attacks the gypsy moth caterpillars as well as the caterpillar of more than 100 other moth and butterfly species
- Allegan County has managed this problem from 1989 through 1998 using only Praxis. Hundreds of millions of Gypsy Moth have died here without a single drop of pesticide being sprayed. Only 1,821 acres were defoliated in Allegan County in 1998.(20) [This is after 9 years of using the wasp]
- Wasp control does not work well in small infestation areas because the wasp have a hard time finding the host.
It works better in large infestations.
A kit can be purchased from Praxis(20)
- Approximately $4,400 per year for the kit from Praxis. This however does not include the additional
materials needed to band the trees etc.(19)
Human Health Risks
- Skin irritations as mentioned above relating to removal of the caterpillar and or the egg sacs.
- I found no information on potential dangers from being stung by the wasp and therefore assume that this is not a risk.
- There is no identifiable risk to health and human safety or to mammals, birds, fish or other beneficial insects.(20)
- The danger that the wasp will attack non-specific species.
- They also have a negative effect of the gypsy moth carcass on the Northern Tiger Swallowtail butterfly. Leaves painted with gypsy moth body fluids and water resulted in 100% mortality of swallowtail caterpillars in a matter of hours.(3)
- Praxix uses no organism that is not native to Ohio or could not fly into Ohio.(20) Pros
1. Not using a chemically manufactured product
1. No information given re the dangers of the wasp itself
2. No assurance that the wasps are gypsy moth specific
3. Treatment must be done annually
4. Cost--approximately 4,500 per year
5. Release of the wasp must be accompanied by the mechanical removal of the Gypsy Moth larva and caterpillars
6. The total process is very time and labor intensive
7. Success depends on the involvement of a great number of citizens in the community.
We have many public areas such as Mills Lawn, Antioch College Campus, Gaunt Park, Ellis Pond Park, and Bryan Center Grounds that will need to be taken care of.
Bibliography for General Overview and Pheromone and Wasp Treatments
(1). Bennett, Pam, Clark County Extension Office, Articles in Springfield Sun