Azadirachtin is an insect growth regulator derived from the neem seed (neem oil), which is often used as a grub killer. Neem sprays can be applied on a lawn to directly target these pests. Once a grub comes in contact with azadirachtin, the oil interferes with a grub’s ability to molt, resulting in its death before it can reproduce.
So... What's a White Grub?
White grubs are the slug-like larval stage of many insects. They root around just below the surface, eating the roots of grass and other plants as they grow. The most commonly encountered white grubs are the larvae of June bugs, European Chafers, Masked Chafers, Billbugs, Oriental Beetles and Japanese Beetles. All of these species start as soft-bodied grubs, and are practically indistinguishable from one another. They are white-colored, C-shaped and often have small legs and tiny heads. Most are between a ½ inch and 2 inches long.
Reproduction Patterns of White Grubs
Because of the variety of species that fall into the white grub name, reproduction methods also vary. That being said, white grubs start out as eggs that hatch and grow into larvae. As larvae, they eat to fuel their transition into adult insects. For most, this process takes about 12 months.
Interested in the more information about how specific grub species develop?
- Facts About Japanese Beetles – The Japanese beetle growth cycle includes time in your lawn as a grub.
- Facts About Crane Flies – These insects start out as “leatherjackets,” another harmful grub.
White Grub Habitat
White grubs are most often found just below the surface of a lawn or garden where they live in the soil. If the soil is exceptionally moist, or at night, they may emerge to feed on the plants in lawns and gardens. In lawns, the damage can often be so extensive that the sod can be rolled up like a carpet.
Using azidirachtin as an effective grub killer will allow your organic lawn or garden to be free from white grubs, which can damage your grass and ruin your vegetable harvest.
Symptoms of White Grub Damage
One of the first signs of a grub problem is an influx of birds to the infested area. Animals can further damage the lawn or garden because they dig up the areas where grub scents are the strongest. A number of animals may be responsible for this damage, including raccoons, opossums and moles. Nighttime visits by skunks to your property is another indicator of a white grub infestation.
Dead spots on the lawn is another giveaway, and in these areas the grass will turn brown and die. This results from the grubs severing roots, which kills the grass. As the grubs move around and feed, a large section of the turf will become so damaged that the grass easily pulls away in large chunks.
Grubs can also cause serious trouble in gardens, particularly rose gardens.
Results of a White Grub Infestation
When grubs infest your lawn or garden, expect the following:
- Brown, dead spots in your lawn.
- Increased animal activity in your lawn or garden.
- Damage to non-grass plants, which may result in their death or stunted growth.
- Above- and below-ground feeding.
- Increased appearances of beetles, flies and other adult insects later in the season.
- A more significant infestation in the following season – unless treated.
How to Test for White Grubs
Dig up a 1-foot-cube section of your lawn or garden and place that dirt in a wheelbarrow. With gloved hands, break up the dirt and look for C-shaped grubs in the soil. If you count more than five grubs in this space, a grub problem is brewing. Also be sure to check the soil exposed from your excavation – if there are any grubs there, add them to your count.
After looking through the soil, remove and destroy the grubs you find and then place the soil back in the hole. Fit the turf back into place and water thoroughly to help it settle back into place.
Why Are White Grubs in my Front Lawn, but Not in My Back Lawn?
Despite being voracious eaters, white grubs need very specific conditions to thrive. You may have a microclimate in a part of your yard. A positive microclimate will promote their reproduction and growth, while another section of your lawn or garden may be the equivalent of Death Valley for grubs.
Further, remember that grubs, and even the adult insects, may not populate certain areas that are hard to get to. For example, if your home sits in the middle of your property and a thin strip of land connects your front yard to your back yard, then the insects may not have found the bridging area that leads to the other part of the yard. Walls, sheds and some types of landscaping can also block the spread of grubs.
The same can happen between neighbors – your lawn may have grubs while your neighbor’s doesn’t. Your neighbor may have already treated his lawn for them or they may not have found the “bridge” between properties.
Azadirachtin is an insect growth regulator that is derived from the neem seed (neem oil). The neem is a tree in the mahogany family, and is native to India.
Safer® Brand NEEM Oil® works in multiple ways to get rid of white grubs. The first effect stops the insect’s molting process, which traps the larvae in its current form while it continues to grow. Next, the neem acts as an appetite suppressant, which triggers a starvation cycle. Finally, the NEEM Pil® treatment also acts as a repellent, driving these insects away from the area.
Each 16 fl oz bottle of NEEM Oil® makes up to 5 gallons of grub-fighting solution, which can be added to a tank sprayer. Alternatively set your mix rate at 2 fl oz per gallon of water.
Apply Safer® Brand NEEM Oil® at the first sign of grub activity. Re-apply Safer® Brand NEEM Oil® after every 7 days or so to affect newly hatched grubs.
As always, follow all instructions completely for application.
NEEM Oil® is OMRI Listed® products, meaning they are compliant for use in organic gardening. As such, these pesticides break down quickly into their natural elements and do not persist in the environment long after application. They are preferable to synthetic pesticides, which leave residue that can remain in the environment where it can affect beneficial bugs or be absorbed by your lawn, plants and vegetables, resulting in accidental exposure to you, your family or pets.