NemaTrident techniques to target chafer grub larvae

Ideal Conditions for Egg Laying and Larval Hatch

Moist soils now make ideal conditions for egg laying, with warmer temperatures supporting larval hatch and feeding activity. However, warm and moist soil conditions are also ideal for beneficial nematode action to target larvae in the early stages of the life cycle, advises Syngenta Technical Manager, Sean Loakes.

Effective Control with NemaTrident B

“Soil temperature consistently above 12⁰C for at least three hours a day is ideal for the NemaTrident B nematode species, Heterorhabditis bacteriophora, specifically selected to target chafer larvae. NemaTrident B can provide highly effective control. New trials have shown how we can best harness these beneficial nematodes in Integrated Turf Management strategies.”

Optimising Nematode Application

Chafer control with nematodes is a numbers game. The more nematodes applied in optimal conditions, the greater the chance of sufficient parasitic worms getting into the active larvae.

“Chafer grubs are adept at avoiding nematode attacks, using their pseudo legs to wipe them off. However, if there are sufficient nematodes, they can overwhelm larvae, even larger instar grubs,” explains Sean.

Application Guidelines and Tips

NemaTrident B nematodes are particularly active at seeking out chafer grubs in the soil. Once they penetrate the larvae, they release bacteria that kill them. Nematodes move through the soil in a film of moisture, so they are best applied when soils are moist and ideally kept irrigated or moist for 14 days after application. “NemaTrident should be applied with NemaSpreader, a blend of surfactants designed to retain optimal conditions for nematode movement. Trials show up to 30% better control when used with NemaSpreader,” notes Sean.

Sean’s Top Tips for success with nematodes include:

• Store in the fridge at 4-7⁰C as soon as possible on delivery
• Pre-mix in lukewarm water before adding to the spray tank
• Remove filters from the sprayer and ensure it is clean
• Apply in a water volume of 500 – 1000 litres/hectare
• Use the Syngenta XC 08 Soil Nozzle
• Always use NemaSpreader with NemaTrident applications
• NemaTrident B should be applied at a rate of five billion nematodes per hectare

Integrated Approach for Reliable Control

Syngenta trials have shown the most reliable and consistent chafer grub control with an integrated approach using NemaTrident B plus NemaSpreader, following an Acelepryn insecticide treatment.

Recent studies at Forest Pines Golf Course in Lincolnshire – using a well-timed application of Acelepryn at peak egg laying, followed by NemaTrident B – confirmed that larger chafer larvae stressed or weakened by Acelepryn may be more susceptible to nematode incursion, delivering more effective overall control.

Timing and Technique for Optimum Results

Timing and application technique are crucial for the best results. Nematodes are living organisms and must be handled carefully from delivery through to application to ensure the maximum number are applied in the best condition.

“Where chafer grubs are the primary target, this two-pronged approach can give the optimum results,” reports Sean.

However, turf managers must note that only one application of Acelepryn is permitted per season, so if leatherjackets are a greater issue, the insecticide may be better utilised there, making NemaTrident B the key asset for chafer grub control.