Predatory Mite (Stratiolaelaps scimitus)
Stratiolaelaps scimitus is a native species of soil-dwelling mite, which feeds on small insects and fungus gnat larvae, pupating thrip, the larval stages of root aphids and small insects. It is an accomplished generalist soil predatory mite. Adults are tan in color, less than 1 mm long (1/20th in.) and move rapidly over the soil surface. They live, eat, and reproduce in the soil medium and walkways on the greenhouse floor. This product has been the cornerstone of the industry for over 25 years, where it has been known as Hypoaspis miles.
Though not listed, Stratiolaelaps scimitus being a generalist may help with root aphid prevention also. Stratiolaelaps adapt well to the various growth media and capillary mats used in plant production, but do not survive freezing or flooding conditions.
Fungus Gnat Larvae, Pupating Thrips, Root Weevils
The optimum temperature required for the reproduction and development this predatory Stratiolaelaps scimitus mite is between 15-25°C (59-77°F). At this temperature range these mites generally complete their egg-egg life cycle within 13-15 days. Stratiolaelaps can also survive as a scavenger in the absence of pests, feeding on algae and plant debris.
Apply 25,000 each per 1,000 - 2,000 square feet. Or 5-10 predatory mites/square feet.
The complete life cycle takes about 18 days at 68°F. The sex ratio is an equal 1:1, females to males. Eggs hatch in 2-3 days into young nymphs, which are also fierce predators that consume eggs and small larvae. Each adult Stratiolaelaps will consume 1-5 prey per day. Populations will naturally fluctuate throughout the growing season.
Stratiolaelaps is most effective when applied before fungus gnat populations become established or when numbers are still low (below 10 per trap, per week). Two applications of Stratiolaelaps per crop cycle are usually sufficient if used early in the season. The second application should be made 2-3 weeks after the first.
Do not water soil or growing medium 10 minutes before and a few hours after release. To release, rotate the canister (to distribute mites inside), then open the lid and remove the filter paper. Place the lid back on, and tap the mites out of the canister evenly onto the soil. Also distribute on floors, greenhouse weeds, under benches, and places where fungus gnat larvae will develop. Stratiolaelaps can be integrated with insect parasitic nematodes (e.g., Steinernema spp.) and Bacillus thurinigiensis israelensis (BTI), both of which control the larval stage of fungus gnats.