Our slow to start and fluctuating spring has earned the region an average of 82 growing degree days. The cool, overcast, damp days had initially given way to warmer than average temperatures but have leveled out to seasonal temperatures for this time of year. Soil temperatures have increased and are appropriate for encouraging root and shoot growth. In the last couple of weeks the region has received 1 to 2 inches of rain, which along with the moisture in the air, has allowed lawns to green up quickly. However, green lawns may be accompanied by weeds, insects and disease. At this time there are a couple of insect issues reportedly sighted or expected to begin affecting lawns soon.
Warming temperatures are finally awakening turf insects. As soil temperatures creep into the 50s white grubs begin to appear on the scene. Visible damage is usually of the “secondary” variety, caused by skunks, raccoons or birds rooting around in the lawn for a nice grub meal. Chemical control may or may not be warranted or effective in the spring; grubs are larger than they were in the fall and their physiology slows in preparation for pupation, your arborist will help you figure out whether or not to treat right now.
Pupal cases of invasive crane flies should be visible soon. In some regions 2 generations of these flies will be produced over the course of the growing season. Overwintering larvae will be completing their development and will soon be finished feeding. Pupae will wriggle up through the soil and stick up through the grass, upon close inspections their brown, leathery pupal cases can be seen. Once these become visible, adults will be out shortly-they look like huge mosquitoes. Adult females will lay eggs within a couple of days, but eggs take about 2 weeks to develop. Young larvae will be actively feeding within 3 weeks, this is the best stage to control with insecticides. If crane flies are found on your lawn during your arborist’s inspection, they will make sure your treatments use the right products to properly control populations, but if you have additional concerns or have not had a spring property assessment, contact your arborist.