White grubs (May or June beetle larvae) can be a problem to control in all areas of Texas. They are often detrimental to your lawn and garden plants. White grubs destroy root systems, causing plants and grass to become weak and possibly die. To make matters worse, when the white grubs mature, the beetles eat the leaves of your favorite plants and trees. The best way to control grubs and beetles is treat or kill them while they are still young, white grubs.
Determine if you have white grubs by taking samples of your soil. Dig down 4 to 6 inches to locate white grubs. Take a sample every 1,000 square feet of space. If you spot more than five white grubs per square foot, you have a grub problem that needs treatment using one of the methods below. If you don’t see grubs, you may have another issue such as a common Texas turf diseased called Take-all Patch.
Spread nematodes (microscopic worms) that will attack the grubs and kill them. According to Texas A&M University, water the area with ¼ inch of water before applying the worms, which mix with water. Spread water with a handheld sprayer or sprayer attached to the hose.
Walk over the area with spiked sandals to aerate the soil. These sandals are sold in many home and garden centers as well as online. Do this often (every two to three days) to kill up to 50 percent of the white grubs.
Apply an insecticide designed to kill white grubs. Choose ones with the chemicals imidacloprid or halofenozide. If grubs are larger than ½ inch, use the insecticide with imidacloprid. In general, the best time to apply an insecticide is early to mid-June in South Texas, and early to mid-July in Central and North Texas. Each insecticide brand is different so always read the label and apply it according to the manufacturer's directions.