TARGET PEST - TWOSPOTTED SPIDER MITE Tetranychus urticae
DESCRIPTION OF THE PEST
Twospotted spider mites are web-forming mites that pierce plant cells and remove their contents. Twospotted spider mites, as the name suggests, have two large dark spots on the sides of their yellowish green bodies. The entire life cycle can take as little as 8 (77° to 95°F) to 28 (50° to 68°F) days, spider mites have many generations per year and can rapidly increase in number.
Twospotted mites suck cell contents from leaves, stippling leaves with a fine mottling. The stippling increases and leaves turn yellow with bronzed or brown areas and frequently fall. Plants may become severely stunted when large mite populations are allowed to feed and the plants may die.
Many different species of predatory mites are available for control of these mites under different conditions. Phytoseiulus persimilis is a predator of twospotted spider mite, and has been used to control mite populations in greenhouses and field situations. It can reproduce faster than its prey, yet best results have been obtained when it is released into the crop well before the spider mite populations have built up.
MONITORING AND TREATMENT RECOMMENDATIONS
Monitor the crop regularly, as indirect sampling methods (such as sticky cards) are ineffective. Observe the undersides of leaves with a 10X hand lens, and watch for changes in plant foliage that are characteristic of mite feeding.
PREDATORY MITE DESCRIPTION - Phytoseiulis persimilis
Like other mites, Phytoseiulus persimilis do not have antennae, segmented bodies, or wings. They pass through an egg stage, a six-legged larval stage and 2 eight-legged immature nymphal stages before becoming adults.
Phytoseiulus persimilis are about the size of twospotted spider mites, but lack spots, are orange in color, and are shinier and more pear-shaped than their prey. The shiny, oval eggs of Phytoseiulus persimilis are larger than spider mite eggs. In addition, predatory mites are much more active than pest mites, only stopping to feed. Under magnification the mouthparts of predatory mites can be seen extending in front of their body while pest mite mouthparts extend downward to feed on plants.
This predatory mite feeds exclusively on spider mites and consumes 2 or 3 adult females or several dozen egg in a day. Phytoseiulus persimilis often needs to be reintroduced as it relies exclusively on mites for food and can eventually consume all available prey. This beneficial mite is commercially available and is commonly released against spider mites such as the Pacific spider mite and the twospotted spider mite. P. persimilis tolerates hot climates as long as the relative humidity is between 60 and 90 percent.
RECOMMENDED APPLICATION RATES
PREVENTIVE - 2,000 per 4,000 square feet every 3 weeks
LIGHT INFESTATION (Less than 1 twospotted mite per leaf average) - 2,000 per 1,000 square feet
HEAVY INFESTATION - 2,000 per 500 square feet
PRICING - INCLUDES SHIPPING Via UPS NEXT DAY AIR
2,000 - $55
4,000 - $100
6,000 - $140
8,000 - $175
10,000 - $205