This weeks Pestwatch report, issued by Dow AgroSciences and ADAS, shows a steady increase in egg-hatch at all sites on both mineral and organic soils. Plant invasion by the larvae has been detected in 4 of the 5 sites. Where justified and where crops have been put through a risk assessment, this is the optimum time to apply an effective egg-hatch soil insecticide such as Dursban WG as egg-hatch is well underway.
Weekly information on Wheat Bulb fly egg-hatch can be accessed on the web at http://www.dowagro.com/uk/cereal/pest.htm and farmers and advisors are encouraged to log on in order to help them assess the risk to their crops and optimize egg-hatch timings, thereby complying with good Stewardship practices. This week’s Pestwatch report indicates that Wheat Bulb fly egg-hatch in Suffolk had increased to 23%, in Cambridgeshire/Hertfordshire on mineral soils it was 33%, in Cambridgeshire on organic land 15.4% and in Lincolnshire on organic soils 21.5%. In Yorkshire egg-hatch development is much slower with only 2.5% of eggs hatched and no plant invasion. Plant invasion is 24% in Suffolk, 10% in Cambridgeshire/Hertfordshire, 2% in Cambridgeshire on organic soils and 6% in Lincolnshire. Pestwatch will be monitoring egg-hatch on a weekly basis up until mid-February.
"This is the optimum time to apply Dursban WG (chlorpyrifos), particularly to crops that have been identified to be at risk. Such crops include late drilled crops, backward crops, thin crops or crops that are struggling as in all these instances tiller survival is more critical. This year, with the highest recorded Wheat Bulb fly eggs since 2004 and the fourth highest since monitoring began in 1984, growers need to take action," says Sarah Hurry of Dow AgroSciences.
"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, which means that most larvae will be controlled 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 Orange Wheat Blossom Midge later on after GS 39 where necessary," she says.
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. For Wheat Bulb fly, two applications at dose rates of 1 kg/ha maybe applied up until flag leaf sheath extending (GS 39). It is packed in a 1 kg pack.
®Dursban is a trade mark of Dow AgroSciences LLC.
