Social Icons

Friday, September 7, 2012

“c-shaped” grub worms


As the weather warms, we will begin to see the adult May beetles (Phyllophaga spp.) flying under lights at night. These adults feed on leaves of several trees including oaks and pecans and can cause complete defoliation of the tree if large numbers of adults appear. Most healthy trees recover quickly from complete defoliation, but stressed trees can be damaged by these attacks.
The female May beetle will deposit eggs into the turf and the eggs will hatch into “c-shaped” grub worms that are creamy white in color with brown heads. The grubs feed on dead organic matter and roots of plants. Since the grubs feed on roots, they can injure roots of grasses and other plants. This causes infested turf to brown and it can be easily removed in large clumps.

Some Control Options:

Irrigating the soil with ¼ to ½ inches of water prior to treatment can improve the effectiveness, since the grubs will move closer to the soil surface. Parasitic nematodes in the genera Steinernema and Heterorhabtitis have been shown to be effective. Insecticides containing imidacloprid, halofenozide, and clothianidin are some active ingredients that are effective at killing the smaller stages of grub worms and ideally should be applied 6 weeks after adults emerge. Lambda-cyhalothrin and trichlorfon are some examples of active ingredients more effective at killing the larger grub worm stages.
“c-shaped” grub worms
Picture of grub worms. Photo by Texas A&M University.

1 comment :

  1. You may mistake grub worms as a type of worm. But, in fact, they are the larval stage of certain beetles like the Japanese beetle, Oriental beetle, Asiatic garden beetle, etc. Adult beetles roam around in the garden and feed on the plants, during the early summer. Around July and August, these beetles lay eggs deep inside the soil, in the moist areas of the lawn and garden. Within a few weeks the eggs hatch and develop into larvae and these larvae are called grub worms. They are plump little worm-like creatures that sport a C-shaped body with a reddish head and dark-colored rear. Grub worms in grass feed voraciously on the roots and in this process, may damage the lawn. Similarly, they feed on the roots of the garden plants, resulting in their death. Even though, they start feeding, as soon as they hatch, grub worms reach their full size within a month and those in this stage are said to cause the utmost harm to the plants.

    Before the advent of winter, they move deep into the soil for hibernation and transforms to pupae during May. They emerge out as beetles in early summer. Some of these grubs may come out during spring and feed for a while, before transforming to pupae stage. But, this time, the feeding is not found to cause much harm to the plants. The presence of grub worms in the lawn or garden can attract skunks, raccoons, armadillos, moles, etc. These animals may dig out soil in the lawn and garden, while searching for grub worms that they devour on.

    ReplyDelete

Related Posts Plugin for WordPress, Blogger...