Making your landscape unattractive to pests

Monday, March 27, 2017

Homeowners take pride in how their homes look. From curb appeal to interior design, the goal is to make their homes look as good as possible.

However, there is a time when homeowners want to opt for the unattractive look – at least when it comes to pests in their landscape.

It’s important to make your landscape as unappealing as possible to unwanted pests, said David Hillock, Oklahoma State University Cooperative Extension consumer horticulturist.

“It can be disheartening for homeowners to work tirelessly in the garden, only to find it has been damaged by pests,” Hillock said. “Fortunately, there are steps gardeners can take that pests will find unattractive, but will still be pleasing to the human eye.”

Cultural control methods include properly selecting and rotating crops, sanitizing and solarizing the soil, choosing the best planting and harvest times and using resistant varieties and certified plants.

Certain pests are more common in some crops than in others. Rotating crops to different sites can isolate pests from their food source or can change the conditions pests must tolerate. Hillock said if your space is limited and no other spot is available, try changing the type of crops you grow in that area.

“Try to avoid putting members of the same plant family in the same location in consecutive seasons. For example, don’t follow melons with cucumbers or squash,” he said. “Waiting two years to plant the same family of vegetable in the same location is the most effective rotation practice; however, yearly rotations also can be beneficial. Rotating annual flower plantings also is a good practice.”

Some organisms that cause damage and insect problems can overwinter in plant debris such as shriveled fruit. Diseases on these shriveled fruit infect new leaves the following spring. It’s important to remove crop residues, weeds, thatch and volunteer plants by either disposing of them in a compost pile or by spading them into the soil to deter pest buildup. This also will eliminate food and shelter for many insects and diseases.

Hillock said soil solarization is another option of cultural control. A clear plastic sheet spread over the soil traps solar heat, which kills soilborne diseases, insects, nematodes and many weed seeds.

“Because of the well-known Oklahoma heat, this treatment should occur during summer’s high air temperatures and intense solar radiation. Keep the soil damp during the solarization process, and keep the plastic in place for several weeks,” he said.

OSU Extension Fact Sheet EPP-7640 explains soil solarization in more detail and can be found here.

Early planting and harvesting also may help avoid heavy pest infestations, but still allow for achieving a full yield. If you plant early, gardeners may have to make use of cold frames or hot caps to protect seedlings from the weather while they get a head start on growing. Stronger, older plants have a better competitive edge over pests. Gardeners also need to be familiar with the emergence times and life cycles of the pests needing to be controlled.

“One of the easiest things to do is simply buy seeds or plants with built-in resistance to diseases and nematodes. When shopping for plants, be sure to check for plants labeled certified or grown and inspected under sterile or quarantined conditions. These plants may cost a little more, but they’re worth it,” Hillock said.