Most gardeners know these days that, in the words of the great Bob Dylan, “the times, they are a changin’.” Organic is the way, or at least most of the time. It’s friendly to you, your plants, your soil, and your budget for the most part. Integrated Pest Management is another way to go which encompasses the friendliest methods of controlling our garden pests as well as includes the last resort of applying chemicals. When thinking Integrated Pest Management or IPM as I will refer to it, one must recognize that a healthy garden will take care of itself just as a healthy human body will easily fight off a virus or minor bacterial infection without the use of prescription drugs.
There are several factors that complete an IPM system for any garden. One aspect is controlling the insect pests in the garden through cultural, mechanical, biological, or chemical means. In this article I’m briefly outlining five of the most common insects that offer biological control of typical pests in the southwest desert garden. It’s important to note, however, if you want to depend on these insects to do your dirty work of killing those nasty pests, then you must refrain from using most insecticides and keep your garden thriving from a complete IPM maintenance system.
Assassin bugs: What a name! They don’t discriminate. They are from the order of “True Bugs”, and will kill their prey by using their long beak or piercing mouth tube and to stick and suck the juices from the pest they have trapped. They tend to be brownish or reddish, and are about half and inch long. They have spiny legs which help in trapping their prey.
Green Lacewing larvae: The lacewing larva is the key here. Attracting the adults is the first plan of action. They are prominent in our desert area, and are attracted to nectar sources like Angelica, Dill, Coreopsis, and Sunflowers. After you’ve brought the delicate light-green, winged adults to the garden then you can wait to find their eggs hanging from thin strands on the underside of the plants they were feeding from. They will only have one egg per strand due to the voracious nature of the larvae and to prevent them from eating each other. Once hatched, each of the larvae can take down up to 200 aphids a week. In general, they attack the eggs and the immature stages of most soft-bodied pests such as: aphids, thrip, spider mites, whitefly, mealybugs, leafhoppers, and the eggs and caterpillars of most pest moths.
Ladybeetles and larvae: Ladybeetles and their larvae feed on a few different garden pests including mealybugs, aphids, scale, and thrip. The beetles themselves are hardy predators but the larvae, like their lacewing buddies, are voracious! Once again, you must attract the adults to the garden first. They are attracted to the same plants as the lacewings as well as dandelions, scented geraniums, and any of your early aphid attracting plants. Think soft stems, easy to pierce through.
Parasitic wasps and flies: These lovely insects are among a large species group. For the most part each one is also quite discriminate as to which pest they attack. Most of the normal garden pests have a parasitic wasp that will attack it. In fact, one species of these little winged assassins, the Trichogramma wasp, attacks butterfly and moth eggs and it is bred and used widely in greenhouse and farm operations to control Cabbage loopers and Hornworm caterpillars. Others will attack aphids only leaving their larva to pupate and eat its host from the inside out. As the larva grows the aphid bloats and eventually the larva eats a little hole in the aphid abdomen leaving the body to harden and mummify, hence the name “aphid mummy” is given to the final phase of the aphid body.
Praying mantids: You won’t get much in the way of pest control from these, but you can bet they will do their part and it will be fascinating! They are such an unusual looking insect, that if anything you want them in your garden for you and your kids to show and tell. They will eat just about anything they can catch and get their mouth around including aphids, mites, caterpillars, flies, bees, moths, and crickets. The young are the most voracious of the life stages, and if there is not a pest to consume they will attack each other. If you bring one of the commercially sold mantid eggs into your garden, try to find one that is from your area.
Remember to make your garden a haven for these and many other beneficial insects. All life flows in a cycle of balance, and your garden is the wonderful microcosm to witness such wonder.