Spider mite larvae, nymphs and adults feed on the underside of the leaves and cause yellow spots,later even yellow leaves. Plant cells turn yellow, which can be seen on the upper surface of the leaf as small yellow spots. This reduces the photosynthetic area of the leaf and the plant gets out of the physiological balance. This results in decreased plant growth and production. Finally the crop may die from the infestation. Nymphs and adults produce webbing that can cause cosmetic damage to the crop. If large numbers of spider mites are present, plants may be completely covered with webs.
- For tomatoes and cucumbers, 10 predator per plant plus 1-2 per infested leaf.
- For other greenhouse crops, tropical plants, and outdoor gardens, 2,000 per 3,000 sq. ft.
- For bedding plants, 4,000-8,000 per 5,000 sq. ft.
- For large agri-business, 25,000 - 50,000 per acre depending on infestation.
Phytoseiulus persimilis This bright orange predator is native to the tropics of South America. It does best in a humid environment of 60 to 90% relative humidity. Does best where tempertures remain below 90 degrees F. Persimilis is sensitive to high tempertures and low relative humidity. A humidity of 60% or lower has a negative effet on the hatching of the eggs and the development of Persimilis. If spider mite problems occur in a hot and dry environment, Longipes or Californicus will provide better control than Persimilis. Persimilis can reduce spider mite population to very low numbers in two to three weeks. Since Persimilis are faster and stronger than their prey they easily catch and eat them. When released they smell their prey, then move quickly throughout the plant. Persimilis work best from tempertures of 50 t0 90 degrees F. They then die from lack of food. In situations where the pest reinfest the plants, we suggest introducing persimilis every 3 to 5 weeks or introducing either Occidentalis or Californicus in combination with Persimilis.
Amblyseius Swirski Predatory Mite, Amblyseius swirskii is an excellent biological control agent and has been used in controlling tiny pests such as whiteflies, thrips and spider mites that cause a serious damage to many economically important crops grown both in the greenhouses and fields. Effective against the following pests: Asian Citrus Psyllid, Broad mites, russet mites, two spotted spider mite, Western flower thrips, •Chilli thrips, Asian Citrus Psyllid, Greenhouse whitefly, and Tobacco whitefly.
Galendromus occidentalis is a very versatile mite predator and tolerates high temperatures low and high humidity (40-85%) well, both indoors and out. Does best in warm weather (80° to 110° F). Tolerates low humidity of inland valleys. Does not do well in cool coastal areas. Goes into diapause (hibernation) in colder temperatures. Recommended for greenhouses only if plants are maintained as low as 40% relative humidity. It is native to California and has ben researched for spider mite control in almonds, grapes, and many other ornamentals and plants. This predator is well adapted for outdoor use and can perform in hot situations where humidity remains above 40%. Use G. occidentalis to control spider mites, two spotted mites, Russet mites, and others on gardens, greenhouses, and orchards of all types. Adults eat 1-3 pest adults or up to 6 pest eggs/day. Release rates indoors, 2-3/sq. ft. bi-weekly, 1-2 applications; outdoors, 5,000-20,000/acre, bi-weekly, 1-2 applications.
Neoseiulus californicus predatory mites consume their prey at a more leisurely pace than do their friends Mesoseiulus longipes and Phytoseiulus persimilis, one adult or a few eggs per day, they can survive longer under starvation conditions and can also live on a diet of pollen. In plants where it is very hard to detect the first spider mites, Californicus may be introduced preventatively, Completes a generation in one to two weeks depending on temperature (12 days at 64º F, 4 days at 90º F). The female lays about 3 eggs per day for two weeks and lives about 20 days. At 77º F the female can consume 5.3 spidermite eggs per day. Does best in warm humid conditions, but will also tolerate low humidity (40% - 80% RH at 50° - 105°F). Occurs along coast and inland valleys of California. PESTICIDES: Susceptible to pesticides. Avoid using any pesticide one week prior or one week after releasing predators. STORAGE: Highly perishable, should be used immediately upon delivery. If storage is absolutely necessary, refrigerate at 40°-50° F. (6°-10° C). Not to exceed 3 days, to minimize mortality. They are not canabalistic and survive shipping very well. Release 1 - 4 per plant or 1 - 2 per square foot in greenhouses at the first sign of spidermites. Use 10,000 per acre in field. Later releases will require much higher numbers to be effective. Releases of californicus can be made when Spider mites are present and laying eggs. even if no spider mites have been found yet. N. californicus need a minimum of 40% humidity and ideal temperatures 60-90 degrees F. Can tolerate temperatures up to 105 degrees F. Works great in gardens and greenhouses.
Mesoseiulus longipes is similar to P. persimilis but can tolerate lower humidity 40% at 70 degrees F. but requires higher humidity as tempertures increase. M. longipes are effective in temperatures up to 100 degrees F, although a comparable increase in humidity is required. Apply these predators in warm greenhouses and interiorscapes with artificial lighting. The lifespan of the adults, the form in which they are shipped, is 34 days. Release rates indoors, 3/sq. ft. bi-weekly, 1-2 times; outdoors, 5,000-20,000/acre, bi-weekly, 1-2 times.