Unsettled weather has resulted in downy mildew being found in early-drilled winter oilseed rape and an early treatment of Quell Flo (mancozeb) will not only protect against this disease, Phoma and light leaf spot, but also add a useful early nutritional boost to get the crop off to a good start, says Dr. David Stormonth, Technical Manager of Interfarm UK Ltd.
"The recent moist, warm conditions have encouraged downy mildew infections. It can be seen as yellowing of cotyledons and first few leaves, with white spore-bearing structures on lower leaf surfaces. Action is required to prevent further spread of this disease as well as other autumn diseases including Phoma stem canker and Light Leaf Spot, all of which cause damage in small crops. The treatment is simple and inexpensive, involving the use of Quell Flo (mancozeb), which can be readily tank-mixed with a pyrethroid for flea beetle control or relevant early post-em herbicides. It would be a very cost-effective start to the disease control and nutritional programme, at a time when growers are particularly sensitive to the cost of inputs in rape," says David.
"In addition to broad-spectrum disease control, 1.5 l/ha of Quell Flo delivers 140 gms/ha of elemental manganese which will improve green leaf production and retention. This is a significant nutritional dose which will help improve canopy colour and management and produce a healthier crop. Better canopy management in the autumn will also help to improve root development and reduce landing sites for pigeons. This extra nutrition is particularly important in the early stages of the crop."
According to Dr. Stormonth, Quell Flo can be tank-mixed with the major triazole fungicides such as difenoconazole, flusilazole, flusilazole + mbc, tebuconazole, metconazole, prochloraz, prothioconazole and prothioconazole + tebuconazole. It is also compatible with pyrethoids, propyzamide products including Engage and Flomide and most graminicides.
"Using Quell as part of the overall disease control programme this autumn is a responsible approach that will ensure that disease resistance does not become such a widespread problem in oilseed rape, as it already is in many other arable crops," concludes Dr. Stormonth.
For further comment and information, please contact Dr. David Stormonth, Technical Manager, Interfarm UK Ltd. on 01354 741414 or 07818 036506 (mobile) or via e-mail david.stormonth@interfarm.co.uk
Quell Flo contains 455g/L mancozeb formulated as a suspension concentrate and packed in 10 litre containers. It has label approvals for use in winter oilseed rape, winter wheat, spring wheat and potatoes. In oilseed rape it recommended at a dose rate of 1.5 l/ha in 200 litres/ha for good coverage. It can be applied up to the end of December in the year of sowing. It has no LERAP and is rainfast in one hour.
