I start today's missive with a quote from Wikipedia.
Hot, dry conditions are often associated with population build-up of spider mites. Under optimal conditions (approximately 80 °F or 27 °C), 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. 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.[3]
Spider mites, like hymenopterans and some scale insects, are arrhenotochous: females are diploid and males are haploid.[4]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.
These are some pictures of spider mite's and their damage. https://www.google.com/search?
As one can see if you have spider mites in your garden and there is warm temperatures forecast (80 degrees and warmer), The gardener CANNOT procrastinate. What ever veggie is under attach will be dead in very little time. Recently while harvesting my snow peas I noticed a small population of spiders. While examining this population I noticed that even though the rest of the bed was quite damp this area was pretty dry. Something that spider mites love. Flushing the drip tape took care of the dry but time was of the essence to deal with these guys. First I hit them with Pyganic an organic pyrethrum spray, followed up the next day with Trilogy (distilled neem oil spray). I am not a huge fan of clarified hydrophobic neem oil but I have found this product to be very good on spider mites and thrips. The oil sufficates the mites. I will then evaluate as to whether there are any signs of spider mites and if there are I will use either Mycotrol (derived from a soil borne bacteria) or Cold pressed Neem Oil. Soap spray can also be used, but I have experienced a photo toxicity where any soap residue on plants causes the sun to burn the plant. By using multiple tools the mites can be attached aggressively. Most sprays are not recommended to be used again within the next day. Usually there is a waiting period of 2 to 3 days. If the first spay does not have a total kill of the population, spiders could very easily be back up to where you started with the first spray. A large population on one veggie may not be able to be saved but it is imperative that the infestation be eradicated so that it does not spread to the rest of your garden. As noted before spider mites abhor water. Very small populations can be controlled with just thoroughly spraying the infected plants with water. With this method it is very easy to drown your plants. Spider mites WILL ALWAYS be found at the top of the plant and on the south side. These are the warmest and driest locations. Pole beans and bush beans I have found to be the most susceptible to mites. I have also found that the native prickly Poppies are very attractive to spider mites and can be used as a trap crop to lure the mites away from your garden . And thus can be irradicated before getting into your garden.
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