Nematodes to Control Chafer and Leatherjackets
The European Chafer was introduced sometime around 2001 and has become a serious lawn pest in the lower mainland. Their life cycle is completed in one year and their population can increase rapidly. Adults emerge from the soil in June to mate. In July the females lay eggs and the small hatched grubs feed on the grass roots. Other wildlife is attracted to the grubs and also cause damage but digging up lawns to get to the grubs as a food source.
Prevention is done by following good lawn-care practices such as raking, dethatching, aerating, consistent fertilization, watering deeply and thoroughly 2-3 times a week and not mowing too severely. Cutting the grass at a 2 -3” height is recommended. This allows the soil to remain cool and moist. Bottom line is that the Chafer beetle seems to target weak lawns. Alternate ground covers, such as microclovers may also make your lawn Chafer resistant.
An infestation can be managed through the use of nematodes which are a microscopic roundworm. They move through wet soil to seek out and infect the grubs. The first larval stage of the chafer is the most vulnerable so time your nematode applications to coincide.
Where insecticide use is not permitted:
- For Crane Fly (Leatherjacket) control, apply nematodes, at recommended rates to the soil, in April through June and then again in September through early November. Minimum soil temperature of 12-15°C recommended. Do not apply when too cold as nematodes will not move.
- For Chafer beetle control, apply in late July into early August.
- Apply in areas of known infestation where specific lawns show signs of infestation.
- REMEMBER: The lawn must remain damp for at least 2-3 weeks after nematode applications as they move in the water between the soil particles and once they dry out, they die.
Applying nematodes is best done at a rate of 500,000 per square metre. The rate of liquid required to dispense the nematodes is approximately 12 litres per 100 square metres. The nematodes can be watered in with irrigation or by hand afterward.
Application methods:
If using a spray tank make sure that the psi is below 300 and filters are removed or your nematodes will be pulverized and killed during application. If a flow meter is not used, it is best to time flow rate into a bucket using only water before nematodes are applied. By timing how long it takes to fill a 20 litre bucket, pump flow can be determined.
Applying nematodes in small areas is best done with an Earthway liquid spreader.
They are an excellent way to dispense nematodes in liquid. They are easy to fill and operate much like a granular spreader except that they spread liquid. They are a little bit harder to push but otherwise take a similar amount of time as granular spreading. Set at the most open setting, which is the black/grey nozzle and the most compact spray (90 cm approximately), the Earthway will apply approximately 6 litres/95 square meters. If applied in a cross pattern (first one direction and then the other) the appropriate rate of 12 litres of liquid with nematodes can be achieved. Make sure the spreader is cleaned after each and every use.
TerraLink orders beneficials every Tuesday morning for delivery the following week. Order cut-off time is 4:30 pm Monday. For large amounts, please inquire with the TerraLink Sales Desk at 1-800-661-4559.