Spider mites, also referred to as two-spotted mites are a serious pest of indoor grown crops. They look like very small, moving dots, visible to the naked eye, but more easily seen using a 10x hand lens. The adult female which is the biggest form, is less than 1/20-inch long.
1. Spider mites live in colonies, usually on the undersides of leaves. One colony often has hundreds of spider mites.
2. The term “spider mite” refers to the silk webbing these pests make on affected leaves.
3. Spider mites reproduce and feed throughout the year, as long as the environmental conditions are met. The warmer the environment the quicker they reproduce.
4. If the environment is suitable their life cycle will be completed in less than seven days.
5. Plants experiencing water stress tend to be more vulnerable to spider mite infestation.
6. As the quality of infested plants drop, female spider mites will seek out other healthier leaves on neighbouring plants.
7. Spider mites damage plants by sucking their leaves’ cell contents.
8. A full infestation of the plant will be covered in webbing from the stem of the leaf to the tips. The webbing may often restrict growth.
How to Treat
Discovering spider mites in your growroom can be devastating, but it can be treated. To fully understand why your growroom or plants have these little black flies or spider webs and to learn how to cure it from your growroom, please read on…
1. Prune leaves and stems to stop infestation from spreading.
2. Keep your plants properly watered. As water stress will spread infestation throughout the plant or plants.
3. Don’t underestimate the development time of spider mites. The hotter the temperature the faster they will develop.
These mites live in colonies, usually on the undersides of leaves. One colony often has hundreds of spider mites. The term “spider mite” refers to the silk webbing these pests make on affected leaves. The webbing makes it easy to differentiate spider mites from other kinds of mites as well as from Thrips and Aphids, which also invade the undersurfaces of leaves.
Spider mites may reproduce and feed throughout the year, provided that the environmental conditions are warm enough, e.g. in a grow room. In hot weather, they reproduce very rapidly with outdoor infestations becoming most severe in summer months. If the supply of food and the temperature are favourable, their life cycle can be completed in less than seven days.
They thrive in hot conditions, with low humidity, but they are very adaptable and can infest plants in less than ideal conditions. In these conditions, they just build up their numbers more slowly. Plants experiencing water stress tend to be more vulnerable to Spider mite infestation. As the quality of leaves drops on seriously infested plants, female Spider mites will actively seek out other plants with healthier leaves, transferring by crawling or by being blown onto neighbouring plants.
Spider mites damage plants by sucking their leaves’ cell contents. Plants can often tolerate a small population of spider mites and the damage they do, but large populations –large enough to cause visible damage to the leaves –will harm the productive capacity of plants, especially ornamental plants. At first, the damage looks like flecking of light coloured dots on leaves. Sometimes, leaves turn bronze in colour. As the mites continue to suck on leaves, they turn reddish or yellowish, and eventually fall off. Usually, large amounts of webbing cover an entire leaf, even buds and growing tips. In fact, the webbing may be so restricting that it distorts, and finally stops, the upward growth of the plant. When this point is reached, the infestation is so severe that it has virtually ruined any chance of a decent crop. Inspect your plants regularly and act fast if you suspect Spider mites have entered your growroom.