Latest Pestwatch report for Wheat Bulb fly

Wheat Bulb fly egg-hatch and plant invasion are advancing rapidly in the East on mineral and organic soils. This week’s Pestwatch report issued by Dow AgroSciences and ADAS indicates that Wheat Bulb fly egg-hatch in Suffolk has increased to 55%, in Cambridgeshire/Hertfordshire on mineral soils it was 45.4%, in Cambridgeshire on organic land 26.6% and in Lincolnshire on organic soils 32.5%. In the North of England the trend continues and egg-hatch development is much slower with only 7.3% of eggs hatched and no plant invasion. Pestwatch can be accessed on the web at http://www.dowagro.com/uk/cereal/pest.htm and will monitor egg-hatch up until mid-February.

Plant invasion by larvae has been detected in 4 of the 5 sites. Plant invasion is 20% in Suffolk, 42% in Cambridgeshire/Hertfordshire, 6% in Cambridgeshire on organic soils and 28% in Lincolnshire. In Yorkshire there has been no plant invasion as yet.

Where crops have been risk assessed and are considered to be vulnerable, this is the optimum time to apply an effective egg-hatch soil insecticide such as Dursban WG. Vulnerable crops include those that are late drilled crops, backward crops, thin crops or crops that are struggling, as in all these instances tiller survival is much more critical. Where egg-hatch has progressed and plant invasion has increased, alternative strategies using different chemistry such as dimethoate may be justified.

"Dursban WG is an effective insecticide and should be applied at egg hatch timing at a dose rate of 1 kg/ha in 200-1000 litres of water. It remains active in the soil for at least six weeks, controlling larvae as they hatch over a longer period of time. Two applications of Dursban WG at 1 kg/ha is permitted on crops before GS 39. A further 0.6 kg/ha can still be applied for OWBM after GS39" says Sarah Hurry of Dow AgroSciences.

For further information, please contact the Dow Technical Hotline on 0800 689 8899.

Dursban WG (75% w/w chlorpyrifos formulated as a Water Dispersible Granule) is recommended for the control of Wheat Bulb fly as well as Leatherjackets, Frit fly and Wheat Blossom Midge. Two applications at dose rates of 1 kg/ha maybe applied up until flag leaf sheath extending (GS 39). A further 0.6 kg/ha can still be applied for OWBM after GS39. It is packed in a 1 kg pack.

®Dursban is a trade mark of Dow AgroSciences LLC.