Keeping a lawn and its plantation healthy is not always a simple thing to do, as there are various pests which are potential of doing damages. Grubs are one of those pests which can be a big lawn problem, as spotting its infestation and getting rid of it are not quite easy. Since grubs commonly reside under the soil bed, the infestation is not always immediately known. Hence, some areas of the lawn might have been seriously damaged before the culprits are discovered. To avoid entire damages to the lawn, we need to pay attention to some signs given by grub infestation in order to discover how severe the infestation is and thus, decide a proper treatment to do.
Signs of grub infestation
Grubs are white-colored larva stage of various insects, including Japanese beetles. Grubs reside under the bed of a grass lawn and can do severe damages. The C-shaped larvae feed on the roots of grass and plants, causing them to displace and eventually die. Starting from small infestation, grub can cause a bigger problem and may cause entire damage to lawns and gardens. Grubs feed on grass and various plantations, but roses are one of the most susceptible plants to white grub infestation. To perform immediate treatment for its infestation, we need to first, check for signs of infestation, such as:
- Irregular brownish patches of lawn which can be peeled easily from the soil. These patches can be peeled and rolled like carpets.
- White grubs residing under the irregular brownish patches. You can check for this infestation by peeling the patch and look under the soil bed. If there is a grub infestation, these C-shaped white larvae can be seen easily.
- Grubs develop into beetles, which can be seen around street lamps and porch lights, and some plantations, such as maple trees, roses, and potentilla. When seeing these adult beetles in around May or June, it is likely that your lawn might be the place they choose for laying eggs and breed.
- Certain lawns are more susceptible to grubs and might receive more severe damages. Sunny west and south-facing lawns are grubs’ favorites because these lawns provide perfect moisture grubs need to feed.
When you have managed to spot grub infestation, you might want to consider some things before applying any treatments for getting rid grubs. This is important as the problem causing damaged soil in the lawn might not only grubs. Chinch bugs and severe drought can also be the culprit. Making sure the infestation of grubs is present will be important to perform proper treatments thoroughly. Hence, pay attention to these things before you choose one of grub removal treatments to performed.
- Make sure you see the white grubs physically. Do not depend on only physical signs of damages you spot on the lawn soil since the damages can be mistaken to be caused by either drought or other bugs.
- Make sure the grub infestation you have spotted does cause damages which can be proven physically. This is important especially when you decide to get rid of grubs using insecticides. A turf with grubs beneath but no damages on the surface does not necessarily need insecticides. Alternatively, use more natural ways discussed later for solving this kind of problem.
- Make sure you use the correct insecticides intended for grubs, since applying weaker insecticides will not kill the grubs, but instead, leave a toxic residue which can be harmful to the entire ecosystem around the lawn, including human beings and pets.
- Make sure you do the treatments at the right time. Treatments with insecticides are best for newly-hatched grubs, which appear in June, while adult grubs might be resistant to this. Hence, avoid the months of September to May to treat grub infestation, especially using insecticides as it will hardly work.
Grub control products
Grubs—white C-shaped larva from various beetles can do damages to home lawns, athletic fields, cemeteries, public parks, golf course fields, and other areas with turf grass. These pests do the damage by eating the roots and reside beneath the soil they attack. White grubs are food sources for some other bigger pests, so that its infestation may result in other pest infestation, such as skunks and birds. To effectively treat white grubs, certain products can be applied, and you should pay attention to some things related to the beneficial products.
- Insecticides used for treating grubs should have the ability to go through the turf. Choose insecticides with chemicals which do not dissolve in the water easily, so that watering will not eliminate its effects. Hence, do not choose products which contain solely bifenthrin, deltamethrin, or permethrin for grub control. Although these chemicals might be effective in treating other small insects and bugs, those will not be strong enough to control grubs, as they won’t move down to the site where grubs feed.
- Different chemicals for grubs work differently in the fall, spring, and summer. Hence, you need to choose carefully. Trichlorfon is effective for spring and fall, while clothianidin and thiamethoxam are effective for summer. However, grubs’ life stages also need to be considered to ensure the products work effectively.
- Before applying any products, it is better to mow the lawn first. This is to make sure weeds are removed and the chemicals can be absorbed well by the soil. This will also remove the protect bees.
- After using any chemical products, make sure the lawn has been watered before pets and humans are allowed to go into the treated areas.
Grubs can definitely be a nuisance and the damages it causes might be severe if not treated as soon as it occurs. There are various choices which can be considered when attempting to kill grubs infesting the lawn. As with some other bug infestation, prevention is the best treatment which will keep the bugs from infesting any of your areas. However, you might fail to notice preliminary signs of potential infestation—beetles lingering on flower and fruit plantations in the garden, for example, and find out that your lawn has already been infested. At this point, thorough treatments are needed in order to kill infesting grubs and hence, restore the lawn’s health. You are able to choose methods you are using for treating grubs based on your personal preference since various kinds of treatments exist.
If your concern about side effects on using chemicals and other killing materials for grubs, you might want to consider biological treatments, which mainly use grub natural predators to feed on the pests and thus, eliminate them from the targeted areas. To perform biological treatments, some methods can be used.
- Using milky spore disease
This is a disease which is considered environmentally safe and effective in treating Japanese beetle grubs. Milky spore disease is released to the lawn and eventually kill grubs infesting the lawn. After grubs die and decompose, the level of spore in the soil raises and helps to prevent further infestation.
- Parasitic nematodes
Nematodes are tiny worms which go under the soil bed and release bacteria into the soil, which are able to kill lawn grubs. Nematodes which will be used for eliminating grubs should be purchased fresh. Mix it with water and spray the mixture onto the soil to let the worms dwell beneath the soil and feed on infesting grubs. Water the lawn before and after applying parasitic nematodes to make sure that they will be able to penetrate the bed of the soil—the part where they are more active.
- Neem oil
Neem oil is a natural insecticidal pesticide, which works as a repellant to Japanese beetles and lawn grubs. To perform a treatment using neem oil, mix two tablespoon neem oil with a gallon of water into a garden sprayer. Spray the mixture directly onto the suspected areas where you spotted some grubs, or to the areas which you think are susceptible to grub attacks.
Chemical treatments can be effective in killing grubs if used while the grubs are still little and have not penetrated the soil bed yet. At this time, the effects of chemicals used will target the white worms directly, since they stay on the surface of the soil. The most proper time for treating grubs using chemicals will be in the late summer when they are newly hatched. Clothianidin is effective for small grubs since this substance works on the surface to kill the grubs.
On the other hand, grub treatment in the spring might be more difficult. It is because the grubs have grown larger and less susceptible to chemicals. They also live under the soil, making it harder for the chemical to target them directly. Frequent rains during spring also make treatment more difficult, since it will wash the applied chemicals away. Hence, you will need chemicals which work faster and penetrate the soil deeper. Dylox is an example of effective, fast-acting chemical for grub treatment during the fall.
Grub control is indeed complicated, as this pest, different from some other ones, live beneath the soil bed, making it hard for the chemicals to target them directly. Grubs also grow into bigger worms which are less susceptible to various treatments. Hence, in order to avoid infestation and severe lawn damages, grub control needs to be performed as early as possible. Ideally, grub prevention and control target adult beetles which are carrying grub eggs, resulting in hatchlings. In order to minimize the possibility of grub infestation in the lawn, you might want to do these preventive actions:
- West and south-facing lawns are susceptible to grub infestation because this kind of lawn does not receive excessive sunlight, which keeps the soil moist and warm—the perfect soil condition for grubs to feed and nest. Hence, if you have this kind of lawn, do preventive actions to get rid of newly-hatched grubs, so that large infestation will not happen. You can spread some diatomaceous earth or grounded egg shells to do the action. DE and egg shells have the same properties—sharp edges, which eventually kill small insects, including grubs. Spread a cup of DE or ground egg shells onto the lawn soil and repeat if washed away by rains.
- Regarding the lawn structure, there are some things to be considered, which may deter grubs, such as:
- Not mowing the grass too short, as short grass can be a dwelling place for Japanese beetles to lay their eggs.
- Mulching the lawn regularly, since this may let you know small infestation of grubs should it exists. Thus, you can treat this infestation as soon as possible. Beetles also prefer compact soil for breeding. Hence, the scattered soil will attract them less.
- Doing a deep watering every once a week, which will strengthen the structure of the soil in your lawn. Grub eggs require a moist environment to hatch well, and this perfect moisture can result from frequent watering. Hence, it is better to do a deep watering every once in a while, rather than frequently watering the lawn, which will keep the soil moist and warm—the perfect requirement for beetle hatchlings.
- Small brownish patches might be the sign of early grub infestation. If you see these, quickly lift the turf to see whether or not grubs are dwelling underneath.
- Overseeding the lawn might be beneficial, as the grass will be too tight and thick, which is less attractive for beetles.
- Fertilize the lawn regularly. Natural fertilizer, such as Epsom salt fertilizer is safe for children and pets and is an effective deterrent for grub worms. To make this fertilizer, you will need:
- One cup of Epsom salt
- One bag of powdered sugar
- Lawn fertilizer
- Mix one cup of Epsom salt and one cup of ammonia. Add water into the mixture and place the solution into the lawn sprayer. Spray the mixture onto the soil, covering up every inch of the soil to make sure its effectiveness.
- Stir 100 mg powdered sugar and 400 mg Epsom salt into the lawn fertilizer using a large spoon or a gloved hand. Spread the mixture onto the soil, covering up every soiled part of the lawn.
- Mulch the lawn thoroughly to make sure the mixture go down into the soil bed.
- Do this regularly every once a week or two weeks to make sure that the soil is healthy and is not compacted to make it less attractive to Japanese beetles, preventing them from laying any eggs which develop into white grubs onto the soil.