These worms are an environmentally safe alternative and are not a threat to humans, pets or landscape plants. An effective insecticide for use on white grubs is isofenphos. Residents should notice a decline in grub worms two to three weeks after application. Always read and follow the label directions for application and disposal of any pesticide. Never use more than the recommended quantity, and only purchase the amount necessary to treat the area where the grubs are active.
Irrigation is also important when insecticides are used to treat grub worms.
Irrigate the lawn immediately after applying a liquid insecticide formula and within 24 hours of applying a granular formula. Avoid runoff that will wash the pesticide off the lawn and possibly into the storm drain system or sewer system, creating water quality problems. To prevent runoff, clay soils may need to be watered several times for short periods because they do not absorb water as quickly as sandy soil. Never apply pesticides before a heavy rain is expected because this could result in runoff into local waterways. Citizens are encouraged to use the hotline to assist city staff in providing quality services at reasonable costs.