Key points
• Trials investigated the efficacy of neonicotinoid and organophosphate (OP) insecticides for protection of winter wheat seedlings against grass grub.
• All treatments investigated showed a loss of plants following emergence when 144 - 240 grass grub larvae were present.
• Protection from grass grub feeding can be provided by Poncho® if feeding stops soon after planting.
• The addition of Diazinon or suSCon Green® to Poncho is required if grass grub larvae are likely to feed beyond 60 - 80 days following planting (when planting occurs in late April).
• In both seasons, protection against grass grub damage was required for approximately 60 - 80 days following planting. However larvae were well fed on white clover and attack could be prolonged if the autumn and winter feed supply is limited.