White Patches on Leaves
- Thread starter MikeW
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max316420
Well-Known Member
Spider mites are members of the Acari (mite) family Tetranychidae, which includes about 1,600 species. They generally live on the under sides of leaves of plants, where they may spin protective silk webs, and they can cause damage by puncturing the plant cells to feed. Spider mites are known to feed on several hundred species of plant. Spider mites are less than 1 mm in size and vary in color. They lay small, spherical, initially transparent eggs and many species spin silk webbing to help protect the colony from predators; they get the 'spider' part of their common name from this webbing. Hot, dry conditions are often associated with population build-up of spider mites. Under optimal conditions (approximately 80ºF (25ºC)), the two-spotted spider mite can hatch in as little as 3 days, and become sexually mature in as little as 5 days. One female can lay up to 20 eggs per day and can live for 2 to 4 weeks, laying hundreds of eggs. A single mature female can spawn a population of a million mites in a month or less. This accelerated reproductive rate allows spider mite populations to adapt quickly to resist pesticides, so chemical control methods can become somewhat ineffectual when the same pesticide is used over a prolonged period.
The best known member of the group is Tetranychus urticae (the glasshouse red spider mite, or two-spotted spider mite), which is common in tropical and warm temperate zones, and in glasshouses. Other species which can be important pests of commercial plants include Panonychus ulmi (fruit tree red spider mite) and Panonychus citri (citrus red mite).
Spider mites, like hymenopterans and some homopterous insects, are arrhenotochous: females are diploid and males are haploid. When mated, females avoid the fecundation of some eggs to produce males. Fertilized eggs produce diploid females. Unmated, unfertilized females still lay eggs, that originate exclusively haploid males.
The best known member of the group is Tetranychus urticae (the glasshouse red spider mite, or two-spotted spider mite), which is common in tropical and warm temperate zones, and in glasshouses. Other species which can be important pests of commercial plants include Panonychus ulmi (fruit tree red spider mite) and Panonychus citri (citrus red mite).
Spider mites, like hymenopterans and some homopterous insects, are arrhenotochous: females are diploid and males are haploid. When mated, females avoid the fecundation of some eggs to produce males. Fertilized eggs produce diploid females. Unmated, unfertilized females still lay eggs, that originate exclusively haploid males.
Humboldt14
Well-Known Member
that first pic with the spider mites web, how long does it take them to do that? is that pic from alot of neglect?
MikeW
Member
No the white patches aren't caused by spider mites. I haven't seen any webs to indicate that the problem is spider mites. Correct me if i'm wrong, the munch patterns caused by spider mites are round? I have seen a few small flies buzzing around the plants. The flies are very small, like a gnat. Could a small fly cause the problem? Sorry I forgot to indicate the information about the flies.
Humboldt14
Well-Known Member
post some pics................
MikeW
Member
Update: Pruned a few leaves of the affected plants (not all of them suffer from this problem) and after a few days, the new growth didn't have these white patches. I do have fly strips in my garden, which don't have very many of the flies I mentioned. Sorry I didn't take any pics, I will this weekend, thanks for the info guys.