Introduction
The twospotted spider mite, Tetranychus urticae Koch, has been controversial in its taxonomic placement. About 60 synonyms included under this species have compounded the controversy.
The body of a spider mite is separated into two distinct parts: (1) the gnathosoma and (2) the idiosoma. The gnathosoma includes only the mouthparts. The idiosoma is the remainder of the body and parallels the head, thorax and abdomen of insects. After hatching from the egg, the first immature stage (larva) has three pair of legs. The following nymphal stages and the adult have four pairs of legs.

Description
The twospotted spider mite is oval in shape, about 1/50 inch long and may be brown or orange-red, but a green, greenish-yellow or an almost translucent color is the most common. The female is about 0.4 mm in length with an elliptical body that bears 12 pairs of dorsal setae. Overwintering females are orange to orange-red. The body contents (large dark spots) are often visible through the transparent body wall. Since the spots are accumulation of body wastes, newly molted mites may lack the spots. The male is elliptical with the caudal end tapering and smaller than the female. The axis of knob of aedeagus is parallel or forming a small angle with axis of shaft.

Twospotted mite

Spider mite development differs somewhat between species, but a typical life cycle is as follows. The eggs are attached to fine silk webbing and hatch in approximately three days. The life cycle is composed of the egg, the larva, two nymphal stages (protonymph and deutonymph) and the adult. The length of time from egg to adult varies greatly depending on temperature. Under optimum conditions (approximately 80ºF), spider mites complete their development in five to twenty days. There are many overlapping generations per year. The adult female lives two to four weeks and is capable of laying several hundred eggs during her life.

The twospotted spider mite prefers the hot, dry weather of the summer and fall months, but may occur anytime during the year. Overwintering females hibernate in ground litter or under the bark of trees or shrubs.

Spider mites are the most common mites attacking woody plants and the twospotted spider mite is considered to be one of the most economically important spider mites. This mite has been reported infesting over 200 species of plant/tree.

The twospotted spider mite is also a serious pest in greenhouses as well as on field grown chrysanthemums. The mites generally feed underneath the leaves and cause graying of the leaves due to mesophyll collapse and yellowing. Necrotic spots occur in the advanced stages of leaf damage. Mite damage to the open flower causes a browning and withering of the petals that resembles spray burn.
All mites have needle-like piercing-sucking mouthparts. Spider mites feed by penetrating the plant tissue with their mouthparts and are found primarily on the underside of the leaf. All spider mites spin fine strands of webbing on the host plant--hence their name.

When twospotted spider mites remove the sap, the mesophyll tissue collapses and a small chlorotic spot forms at each feeding site. It is estimated that 18 to 22 cells are destroyed per minute. Continued feeding causes a stippled-bleached effect and later, the leaves turn yellow, gray or bronze. Complete defoliation may occur if the mites are not controlled.

Management

For detection of spider mites, a 10X to 15X magnifying glass is a necessity. Examine the undersides of the leaves closely for mites, cast skins and webbing. A more efficient technique is to place a sheet of white typing paper beneath the leaves and strike the foliage sharply. The mites will fall onto the paper and can be more easily observed and identified than on the green foliage.

Predators are very important in regulating spider mite populations and should be protected whenever possible. Important genera include the predatory mites, Amblyseius, Metaseiulus, and Phytoseiulus; the lady bug, Stethorus; the minute pirate bugs, Orius; the thrips, Leptothrips; and the lacewing larvae, Chrysopa.

Spider mites are commonly attacked by predator mites. Five species are commercially available in the U.S.: Phytoseiulus persimilis, Mesoseiulus longipes, Neoseiulus californicus, Galendromus occidentalis and Amblyseius fallicus. Predatory mites can be distinguished from spider mites because of their longer legs. The front pair of legs is often extended forward. They are more active and move about at a fast pace. They are often red or orange in color. P. persimilis is the most common predator and preys on all stages of mites. It can consume 20 eggs or five adults daily.

Overwintering mites may be reduced in numbers by the destruction of weeds such as pokeweed, Jerusalem oak, Jimson weed, wild blackberry, wild geranium and others.
Insecticidal soaps and oils should be carefully considered when a pesticide is required. They are effective against mites and the least toxic to people, other non-target organisms and the environment. The effectiveness of laundry soaps, washing detergents, and vegetable oils is less consistent than with chemical pesticides. Although some growers have been quite pleased with the results of non-insecticidal quality soap and oil use, some have been disappointed. Also, plant varieties differ in their susceptibility to burning induced by soaps and oils. Environmental conditions, as well as micronutrients, fertilizers, and other additives may affect a tendency to "burn" foliage. At higher rates of application, (2%), burning and stunting are more likely. The twospotted spider mite develops a resistance to most acaricides after prolonged use. Most miticides are not effective on eggs. Therefore two or more applications of the miticide will be required at five-day intervals during the summer or seven-day intervals during the winter.

__________________
PEACE.
Never stop growing.
Seeds are the future.

One should always get to know their enemy before they go to war with them!!

__________________
PEACE.
Never stop growing.
Seeds are the future.

if you are in flower like i am i suggest handwashing the plants at LEAST once a week..along with using neem oil an dutch masters penitratior...peace

I like to try to keep it organic, But sometimes you need to drop the BOMB's!!

Here are some Home made methods for those who haven't seen them.
>>Click>>Home Made Pest control,(mites, aphids, mealybugs):<<Click<<

__________________
PEACE.
Never stop growing.
Seeds are the future.

I have a question about using spider mite predators -- won't previous attempts with pyrethrum, azatrol, sm-90 affect the predators too?
will they die from eating spider mite eggs that have traces of insecticide? will they be equally affected by sm-90 or other types of organic oils that are commonly used for mites?
are the smaller predators better than lady bugs? (I ask this question b/c lady bugs are available at most garden stores, while the more obscure predators have to be mail ordered).

Usually it is wise to make sure all previous traces of anything are totally gone before introducing benificial insects. It will work equally well on them. Although some insects are fought with benificail fungi and mites and I do not know if they are affected. I know fungi is not. Not sure of the mites.

P.S. and there are beneficial bacteria as well. Some attack moths, others attack different types of larvae. They would be fine as well.

Peace

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Life,
j-angel

aka GP purrie kittie attack cat!


My Little Grow LST'ing w/Hardware

My Outdoor Odyssey 2008 BONSAI MUMS

My Little Grow Indoor To Outdoor 2009

anyone tried this nylar pco fogger?
Hydroponics, Indoor Gardening Supplies, Hydroponic Systems - home
(sorry the link takes you back to the home page -- just do a search with the word "nylar" and you will see the different products.)
It contains "ETOC" which is a synthetic pyrethroid "with exceptional flushing, knockdown and killing properties" The nylar is a "growth regulator which arrests the development of preadult insects, preventing reproduction."

this stuff looks good but how toxic is it?? Ill stick to my organig ways...

__________________
PEACE.
Never stop growing.
Seeds are the future.