Grub control at the moment has very limited options. The only option is nematodes.These are microscopic worms that seek out their host and infect them. Since you can not use the same species of nematode for different insects. Chose the right nematode for the insect you are trying to control.
When to apply Grub Control
Spring applications of nematodes are generally ineffective. Grubs in the Spring are usually too large and the nematodes are less effective.The cool weather and soil temperatures will also reduce the effectiveness of nematode applications in the Spring.
August is the best time to apply nematodes for grub control. The grubs are pretty small and the soil conditions are warmer. It is best if two applications are done 15 days apart . The homeowner must water the day before and the day of the application. Grub control can go into November but the variety of nematode changes due to cooler conditions.
Applications should if at all possible be made on a cloudy day as nematodes are sensitive to sunlight. Nematodes need to be fresh they are a live product and will perish sitting on store shelf over winter.
Research Of Nematodes for Grub Control
According to the latest research, nematodes control grubs 50 percent of the time. It has been determine that nematodes will only control 50 percent of the population at any time. After multiply years of nematodes applications the best you can achieve is 60% control.