Of late, your lawn develops some gray and brown patches. Some parts of the lawn may feel spongy, and the grass detaches easily from the soil, as if there are no roots. Even the flower beds show signs of damage with some plants dying all of a sudden. You may also notice some parts of the lawn/garden being dug overnight. All these signs may point towards presence of grub worms in your flower garden and lawn.
What are Grub Worms?
You may mistake grub worms as a type of worm. 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 plants during the early summer. Around July and August, they 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, which 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 damage the lawn. Similarly, they feed on the roots of garden plants, resulting in their death. Even though the larvae start feeding as soon as they hatch, grub worms reach their full size within a month, and those in this stage cause the utmost harm to the plants.
Before the advent of winter, they move deep into the soil for hibernation, and transform 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, their feeding may not 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.
How to Get Rid of Grub Worms
In small numbers, grub worms may not cause much harm to your garden plants or grass, but in large numbers, they can be a serious threat. It has been observed that regular watering, mowing, and normal fertilizing can prevent the damage that can be caused by grub worms. However, if a square foot of the soil in the lawn or garden has more than five grub worms, then you have to search for some large-scale measures to get rid of them. Even though there are various types of pesticides that can be used for eliminating grub worms, it will be always better to try natural pest control methods, as a first line of defense. If the infestation is not that large, then try to attract grub worm predators, like birds (robins). Try frequent watering, so that the grass recovers from root loss.
Beneficial Nematodes: Get some nematodes from the garden store. Mix them in water, and spray on the garden soil or lawn. Beneficial nematodes are microscopic worms that can enter the body of certain insects and their larvae and kill them. These nematodes enter the body of the host and kill the later within two days. However, they need moist soil to travel deep and so, water the soil thoroughly, before and after applying nematodes. However, this method is said to be more beneficial, when the larvae are small in size. So the best season for using beneficial nematodes is July end or early August.
Milky Spores: You may also resort to application of milky spores (a bacterium that can cause milky spore disease in grub worms) on lawn grass. These spores affect the grub worms that feed on the grass and eventually kill them. Nowadays, commercial products for grub worm prevention are also available in the market. You have to apply them during summer, to prevent these pests.
Homemade Pesticide: Add two cups of antiseptic mouthwash (without flavor), two cups of plain liquid soap, two cups of chewing tobacco juice (can be made by boiling chewing tobacco with water), and a cup of household ammonia, to a gallon of boiling water. Once cool, this mixture can be sprayed on the soil/grass, so as to get rid of grub worms.
Contact your local nursery or a horticulturist for more information and instructions about grub worms. Get a detailed understanding about the method to control grub worms to be used and the right time for its use.