byline: Susan Brown, Horticulture Agent, N.C. Cooperative Extension
NORTH CAROLINA — Each year I plan my garden and get started as soon as the temperatures warm up. In the spring, my plants flourish with little care. As the season progresses, I begin to spend more time in the garden, pulling weeds, deadheading perennials and watering more often. Then the heat of the summer hits and the battle begins. I find aphids on my roses and hornworms on my tomatoes.
Flea beetles attack my sweet potato vine and thrips create streaks all over my annual vinca blooms. Should I panic? Reach for the soapy spray? Will my helpers come to my aid again this year? Without fail, a few days later I notice several lady beetles wandering among the aphids, dining contently.
When most people think about insects, they immediately think of pests. But not all of them are. Many insects help pollinate flowers and reduce the population of insects that are harmful to plants. Encouraging beneficial insects to reside in a yard only takes a few minor changes in gardening.
Beneficial insects need a stable habitat to stay happy and healthy. This includes a steady food supply and places to take refuge during storms. If shelter is provided where insects can find protection during bad weather, they are more likely to stick around. Plots of cover crops, perennial flower beds and hedges near flower and vegetable gardens all provide shelter for beneficial insects.
Just like everything else, insects need water to survive. Providing a small, shallow container will work, but change the water every two to three days to discourage mosquitoes from breeding. Place small sticks or rocks in the water to give the insects a place to perch.
When pest populations are low, beneficial insects will feed on pollen, nectar or plant juices to supplement or replace their insect diet. Make sure they have access to this alternate food source in the yard by planting a wide variety of flowering plants to bloom throughout the year.
If pest levels temporarily run low, it is no problem. Beneficial insects can hold off laying eggs when no pests are present or if pest populations are not high enough to feed their hatching young.
In order to sustain their food source, beneficial insects must allow some of their prey to feed and reproduce. They may not be able to solve all pest problems Choosing the right plant for the right place, selecting plants that are resistant to pests and enriching the soil are all sustainable ways of managing pest insects.
Pesticides are another option, but should always be the last resort. Often people spray and kill pests as well as beneficials, but it takes longer for beneficial insects to rebuild their populations.
Many beneficial insects are small and unfamiliar. When an unknown insect is found in the garden, begin with the proper identification of the pest and plant host. Observe if the insect is munching on leaves or buds or if they are feeding on other insects. Are they flying or crawling? What is their physical appearance? These questions help determine the type of insects.
Insects can then be categorized as bad, benign or beneficial. Ninety percent of insects are either benign or beneficial. Even seemingly bad insects serve a purpose, whether it is pollination, decomposition or food for other creatures higher up the food chain.