Early Mildew control reaps yield beneifts

UK - March 26, 2007

If growers and advisors are hesitating whether to include a mildewicide at T0 timing, they should be urged to do so as early preventative mildew control in cereals will pay dividends, according to Dow AgroSciences.

"Trials work clearly shows that a higher percentage yield loss comes from early mildew infections.  If mildew comes into the crop at Growth Stage 24 or 26, trials work shows that yield loss can be as high as 50%.  A little later at Growth Stage 30 the yield loss is still 47%.  These growth stages are all within the traditional T0 window.  If mildew comes in later still, say Growth Stage 32, yield loss is still over 30%.  Market research data shows that on average 18% of mildewicides are used at T0 timing and 40% used at the T1 timing, meaning that 42% is used later when yields have been severely affected," explains Liz Tomkinson, Fungicide Specialist for Dow AgroSciences.

"It makes sense to keep on top of mildew and take it out early as a priority.  Waiting until you see the white pustules before spraying will be counterproductive and you will be chasing it all season.  Adding a robust cost-effective dose of Fortress in with your chlorothalonil at T0 will ensure long lasting mildew protection for 6 to 8 weeks, which may help prevent further applications later in the season," points out Ms. Tomkinson.

According to Liz, T0 treatments are normally applied from late tillering to GS 30 and aim to take the pressure off the T1 spray and delay the development of Septoria tritici.  "If there are specific diseases such as mildew and rusts to consider, these should be targeted as stand-alone diseases and treated as early as possible.  This year a T0 treatment will be even more essential as crops have a good yield potential but are already suffering from high disease pressure.  With the high percentage of mildew-susceptible varieties, early drilled crops, high disease inoculum and recent weather favouring this disease, mildew will be a problem that needs to be tackled right at the start of the spray programme." 

"In addition, Fortress (quinoxyfen) is one of the most cost-effective mildewicides available.  At average use rates, it is 30% cheaper than metrafenone or proquinazid based fungicides so its inclusion in a T0 treatment will deliver yield benefits and cost savings.  It can also be easily tank-mixed with a range of products with no fears of  crop effects," says Ms. Tomkinson.

"If planning to use a product such as metrafenone later in the programme, then Fortress with its different mode of action fits in well with an anti-resistance management strategy where products with different modes of action should be alternated," reminds Liz.

Fortress contains 500 g/litre quinoxyfen, formulated as a suspension concentrate.  It is a systemic protectant fungicide giving protection against powdery mildew on new plant growth.  It is recommended on all varieties of winter and spring wheat, barley, oats, rye, triticale, durum wheat and sugar beet.  It has been accepted by the Brewing, Licencing and Retail Association for crops destined for processing.  In cereals the average dose rate is between 0.1-0.2 l/ha.  Dose rates are flexible according to the variety and length of persistence.  Fortress should be applied in the spring at first signs of disease up until Growth Stage 49.  It is rainfast in one hour and is packed in a 1 litre container.