Monday, July 5, 2010
Because we had such a wet winter insect populations are at an all time high. There have already been reports of Blister Beetle swarms and we had a really nice Swallowtail Butterfly farm on the dill at the nursery. These are 2 good examples of when to break out the big guns and when to just enjoy the show. I realize that no amount of prevention will keep a swarm of Blister Beetles from cleaning out your vegetable garden or landscape but it is the key to keeping destructive bugs in check. Keep plants healthy by watering correctly and using organic fertilizers. Insects love to feed on plants that are drought stressed and enjoy the weak, fleshy growth produced by frequent applications of Miracle-Gro or other chemical fertilizers. Another way to discourage harmful insects is to attract the beneficial insects that feed on them to your yard. Good bugs prefer the nectar of annuals and perennials with small flowers. These would include parsley, thyme, chamomile, hyssop, lovage, lavender, alyssum and marigolds just to name a few. Know your friends. Ladybugs, Praying Mantids, Lacewings, Ground Beetles and many tiny wasps are all helpful in the garden. Check your plants frequently for sign of insects including the undersides of the leaves where insects like to hide and lay their eggs. A few holes in a few leaves is not cause for alarm. If the majority of the plant is healthy and unaffected and you don't see any insects the damage was probably caused by the wind or a bug just passing through. If an insect is not attached to a plant or eating a leaf he is probably a good guy. Once you have identified a real problem use only organic pesticides. Chemical insecticides are non-selective and destroy all insects. Bad bugs recover more quickly than their predators making each consecutive infestation worse and harder to control. Organic insecticides can be very selective leaving good insect populations to help control the problem. The most common garden pests are a variety of sucking insects. They insert their proboscis into the plant tissue and suck out the juices excreting a clear, shiny, sticky substance called honeydew. Seeing this honeydew may be the first sign of a problem. You may also notice misshapen and curled leaves or blossoms that are brown around the edges and fail to open. Thrips are almost microscopic and look like pieces of tan thread. Aphids are tear shaped about 1/8 of an inch long and can be green, black, brown, yellow and with a woolly white coating. Spidermites can be detected by their webbing and are visible when you tap a leaf or branch onto a white piece of paper. They look like little brown specs but they move. All of these soft bodied insects can be controlled by first washing them off with water and then applying Safer's Insecticidal Soap. This insecticide contains potassium salts that will dry out these insects and not harm beneficials. Scale is also a sucking insect but since it forms a protective waxy coating over itself once it attaches to your plant most insectides don't work well against it. Horticultural Oil will coat the scale and smother it. Beetles that feed on foliage such as Flea Beetles, Cucumber Beetles or Blister Beetles can be controlled with a dusting of Diatomaceous Earth or Safer's Yard and Garden which contains pyrethrin. This will kill all hard bodied insects including Squash Bugs but also Ladybugs and other beneficials so use it selectively. Caterpillars that eat the leaves of plants like Cabbage Loopers and Tomato Hornworms can be handpicked or controlled with BT (bacillus thuringiensis). Some caterpillars are the larvae of those colorful butterflies you have been trying to attract to your garden. So if it is something you can afford to share, like the dill at our nursery, you might just let them enjoy it. If you check your plants frequently and try to balance your environment most insect attacks won't get out of hand. If you have questions about a particular insect, put it in a jar and bring it to the nursery and we can most likely help you identify it and offer a solution to it. See you soon.