Tip Top Bio-Control Technical Bulletin

Heterorhabditis marilatus
Beneficial Nematode

Target Pests:
Heterorhabditis marilatus attacks many of the insect species previously attacked by Heterorhabditis bacteriophora. It is somewhat cold tolerant, making it particularly useful should damaging populations be held in check by using a natural enemy to eat the H. marelatus. H. marelatus helps control grubs or immature stages of the following pests very well:

May/June beetles, Black vine weevil, Colorado PotatoBeetle, Other white grubs, Carrot weevil, Flea Beetle, Bill bug, Strawberry root weevil, Bagworms, Banana weevil and Banana moth, Citrus root weevil group, Flea, Sugarcane stalk borer, Japanese beetle, Asparagus beetle, Cucumber beetle, Sweetpotato weevil, Masked chaffer, Various tree and vine borers.

Product information:
H. marilatus is shipped on a sponge, in a paper pouch, or in injectors. Nematodes on the sponge or pouch can be easily extracted into water and applied using conventional spray equipment, hose-end sprayers, watering cans, or distributed through pressurized irrigation systems (not soaker hoses). Nematodes packaged in the paper pouch have no carrier to clog sprayers or grow mold. The nematodes are simply rinsed from the pouch into the spray solution. The pouch formulation has a slightly shorter shelf-life than the sponge formulation. Our nematodes are packed in small plastic injectors that can be used to inject nematodes into bore holes made by wood and stem boring insects or into flower pots and other in-door uses.

Release Rates:
1 million per 50 square feet and 1 billion per acre. The number of nematodes and the number of applications needed also depends on temperature and moisture content of the soil or media. The more regular the watering system, the lower the required rate. The type and numbers of pest and whether it is in the larval stage are also important variables.

Soil temperature should be greater than 45° F to apply nematodes. They will live but not grow very well above 45° F. When soil reaches 60°F, nematodes will grow and parasitize insects. Late evening or night is best and never when the ground is hot and dry. Water dry soils before applying. The best conditions are cloudy, cool weather in spring or late summer while the soil temperatures are below 85° but above 60° F. When using coarse sprayers, pressures can be set up to 300 psi. The mixture can also be distributed through an irrigation system.

Lifespan:
Use suspended nematodes right away. They will drown in the water. The suspended nematodes survive a few hours depending on temperature, oxygen in the water and some other factors. To check viability, examine a drop of the suspension with a hand lens. Live nematodes will be moving in the water drop.

Strategic Considerations:
Nematodes don’t harm beneficial organisms such as lady beetles and earthworms. They don’t pollute our natural resources and are harmless to us and our pests. They are exempt from registration by EPA, and by using them you avoid toxic chemical pesticides, reduce groundwater pollution, prevent secondary pest outbreaks, and development of pesticide resistance in insects. Nematodes are easy to use, as a liquid that can be sprayed or granules to be spread.