Grub worms crawling around on your your flowering potted plants can be alarming, particularly if the pots are in your home or work area. Grub worms are more than just alarming to look at. These large larva stage insects feed on roots stressing the plants. Fortunately, these large insects are easy to identify and remove from your potted plant collection.
Grub worms grow 1 inch long and form a curved, or C shape. These fleshy worms are the larva stage of the May beetle, also commonly called the Junebug. The adult females lay eggs under the soil, usually 2 to 5 inches deep. One month later the grub worms, called larva, emerge and begin to feed. The larva stage lasts for several months as the grub worm feed though the winter. In spring they emerge as adult insects.
Grub Worm Damage
Grub worms feed on roots as while they exist in the larva stage. They affect lawns as well as vegetable gardens and ornamental plants. If you keep your potted plants indoors all year, its unlikely grub worms will turn up. Plants that spend the summer outdoors are more likely to have grub worms feeding in the soil when you bring them indoors. Go ahead and put plants out for the summer but take a few precautions when you bring the plants in at the end of the season.
Grub Worm Control
Remove grub worms from potted plants before you bring them indoors in the fall. If you notice grub worms in flower pots that remain outdoors year round, remove the grub worms to improve the health and vigor of your plants. Place the entire flower pot in a bucket of water. Make sure the water covers the lip of the pot. This dislodges insects like grub worms causing them to crawl out of the soil.
Repot plants to get rid of grub worms. Plants need to be repotted every few years anyway as the potting soil breaks down and the roots outgrow their environment. Repot in the fall when you bring your plants indoors and use the opportunity to get rid of grub worms and other soil pests. Shake as much soil off the root ball and pick out any larva you see. Repot using fresh potting soil.