I visited with a farmer this past week about an issue with the grass in his pastures. When we have issues in the lawn they can be an eyesore, but if we have issues in pastures we lose valuable energy for the livestock. So, I wanted to make sure we identified the problem and take action to correct the issue. The issue was an insect, one that is well known this time of year, the green June beetle or June bug.
These beetles are velvet green with orange or rust stripes. The size of the beetle can range from one-half -1 inch long. Peak flights for this beetle is in June, the reason we call the beetle, June bug. Their flight this year seems to be somewhat late, because we are just seeing high numbers of the insect. These beetles prefer sandy soils; we have plenty of this in Effingham, which makes it easier to tunnel.
Green June beetles have one generation each year. Currently, we are at a point in the cycle were the females are laying eggs (10-30 per female). From this point, the eggs in the soil will grow to become grubs. These grubs will overwinter in the soil. During warmer days in winter, these grubs will be active. Fresh mounds of trails or pulverized soil can be spotted during these warm days. This activity will increase as spring approaches until finally we have adult beetles emerge and they take flight.
Can these bugs cause damage? It depends. If the population is high enough in your yard, it could warrant controlling the pest. Grubs are capable of pruning the roots of plants. These grubs also attract birds, armadillos and skunks. I get several calls about armadillos and if you want to reduce armadillo traffic, you remove the food (grubs). The adult beetles can feed on fruits such as apples, peaches and figs.
How do we determine if we have enough beetles to spray? If you apply a 1-2 tablespoon of lemon dish detergent mixed in 1 gallon of water over a 1 square foot area, this will cause grubs to come out of the ground. If you see more than 4, you may want to consider controlling the insect. The best time for control is generally August-October, I would suggest trying to control in September-October since we had a later flight this year.
If your soil is dry, irrigate before application. Make applications late in the day because the grubs move to the surface during the evening. If you follow these tips, you should have a better control of the grubs.
The good thing is if we miss an application for these insects, our turfgrass will probably survive. But, if our farmers miss this application and the June bugs populations are high, they can lose a lot of valuable food for the livestock.
For more information or questions, contact Effingham County Extension Agent Sam Ingram at 754-8040 or email@example.com.