Friday, May 9, 2008

Insects in Your Garden

In California, more than 30,000 types of insects are known. In spring, it may seem that most of them are in your backyard. This is because warm temperatures are ideal for many insect lifecycles. After just a few warm days, large populations can hatch and inhabit fruit trees, shrubs and vegetable beds. Aphids, for example, may seem to multiply overnight. Hoplia beetles are another insect frequently seen in the garden, especially on light colored roses.

While trying to eliminate these pests from your garden, remember that other insects live there too, and frequently consume insect pests. The use of insecticides, even organic ones, may have a negative impact on beneficials. Always read labels carefully, and avoid spraying when beneficial insects such as honeybees are active.

The number of destructive insects in general is actually quite small in comparison with those that are beneficial or neutral. Beneficial insects eat pests, pollinate crops and decompose waste material. These insects include ladybugs, preying mantids, spiders, assassin bugs, and ground beetles.

Beneficial insects feed in two ways: predation or parasitism. Predation is the method most gardeners are familiar with, the typical ladybug eating an aphid. Parasitism is not as easy to spot. To find an example, observe that same population of aphids, but look closer. If you see small, round, papery-thin objects with a tiny hole, you’ve spotted an example of parasitism. This remnant was actually an aphid, and is now known as a “mummy.” When it was alive, this aphid was parasitized by a tiny wasp (not the same kind that inflicts a painful sting). The wasp laid an egg inside the aphid, the egg hatched, fed on the aphid from inside, and then crawled out, leaving a small exit hole.

Spiders are another creature commonly found in the garden, and sometimes the house. They are not considered insects, but are in a class known as arachnids. Spiders are excellent predators and can be very helpful in the garden. Two “spiders” that are often confused are the harvestman (not a true spider) and the cellar spider.



Harvestman and Cellar Spider

Both of these creatures are reputed to have poisonous venom, which is not true. The harvestman does not have venom, and the cellar spider’s venom is harmless to humans.

In closing, knowledge is the key to overcoming myth and fear. Now that you know how harmless these two species are, having them in your garden or home might be considered a bonus. :)