Wheat Bulb fly marches on

According to this seasons final Pestwatch report, issued by Dow AgroSciences and ADAS, Wheat Bulb fly egg-hatch and plant invasion continue to advance very rapidly in the East on both mineral and organic soils. The final report shows that Wheat Bulb fly egg-hatch in Suffolk has now reached 71.7%, in Cambridgeshire/Hertfordshire on mineral soils it was 75.8%, in Cambridgeshire on organic land 72% and in Lincolnshire on organic soils 64.5%. In the North of England egg-hatch development is starting to catch up with 27% of eggs hatched but still no plant invasion to report.

In Yorkshire there has been no plant invasion by larvae, but at all other sites plant invasion is moving rapidly. Plant invasion in Suffolk now stands at 42%, in Cambridgeshire/Hertfordshire it is 50%, in Cambridgeshire on organic soils 32% and in Lincolnshire 60%.

Pestwatch can be accessed on the web at http://www.dowagro.com/uk/cereal/pest.htm and has monitored pest activity for six weeks.

Where crops have been risk assessed but plant invasion is not too high, an effective egg-hatch soil insecticide such as Dursban WG. 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 egg hatch insecticide. It is applied at a dose rate of 1 kg/ha in 200-1000 litres of water and remains active in the soil for at least six weeks, controlling larvae over a longer period of time. Two applications of Dursban WG at 1 kg/ha are permitted on crops before GS 39. A further 0.6 kg/ha can still be applied for Orange Wheat Blossom Midge (OWBM) later in the season, with the latest date of application before flowering at GS 59, says Sarah Hurry of Dow AgroSciences.

This is the last PestWatch for Wheat Bulb fly this season. It will start up again in March for leatherjackets and in May for Orange Wheat Blossom Midge.

For further information, please contact Sarah Hurry, Dow AgroSciences on 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.