As we approach summer with longer, warmer days, our lawns will encounter greater insect populations. Careful routine scouting and recognizing damaging insects and their beneficial predators can help reduce the need for applying insecticides.
A few years ago I was scouting a newly sprigged field on a commercial sod farm for potential disease and insect damage. I noticed a young caterpillar crawling along the soil between two sprigs of grass. As the caterpillar got close to one of the grass sprigs a spider darted out and ambushed the caterpillar. Healthy lawns are inhabited by a multitude of beneficial insects and other small invertebrate predators like this small spider that feed on plant debris, fungi, and other insects. Almost all turfgrass pests have one or more natural enemies that can be important in suppressing their populations. Natural predation is a legitimate explanation why pest outbreaks are more uncommon in low-maintenance turf than in many higher maintained lawns. There are documented cases of outbreaks of southern chinch bugs on heavily insecticide-treated lawns, but not on neighboring untreated lawns where predators were abundant.
Many conventional insecticides are just as toxic to beneficial insects as to the targeted pests. When we apply insecticides to our lawns we are very likely destroying the natural enemies of the pest insects as well. I am not advocating that we do away with insecticides. They are certainly warranted when thresholds are reached, but be prudent in their use and apply them only when and where they are needed.
Good turf management, including pests scouting, will help provide a wiser, more effective use of pesticides. Be observant of increased numbers of birds feeding in the lawn or wasps hovering just above the turf canopy as these can be great indicators to look closely for an outbreak of caterpillars and other destructive turf pests.
Published May 16, 2011
Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. wwells@ext.msstate.edu
