Increased barley prices make fungicides an easier choice in 2011. Mike Abram reports

 

Deciding how much to spend on fungicides for either winter or spring barley crops in most recent years hasn’t been easy. But this year it should be different.

Low grain prices had made the return on fungicides tight in both barley crops.

For example, the yield responses from popular winter barley varieties on the HGCA Recommended List range from 1.6 to 1.9t/ha. At £80/t that was worth £128 to £168/ha before taking into account fungicide costs.

The programmes used in HGCA RL trials are more comprehensive than those used commercially, which typically range in winter barley from £50-70/ha. At that cost you needed around 0.7 to 0.9t/ha yield response to pay for fungicides in winter barley.

In spring barley, the level of response seen in HGCA RL trials was only 0.7-0.9t/ha, and led to growers questioning their use.

But at the current grain prices, there shouldn’t be any need to economise on disease control, with yield responses on only 0.3-0.4t/ha required on malting barley to pay for typical winter barley fungicide programmes says Simon Oxley, a plant pathologist with SAC. “At £80/t the increase in yield you achieved did pay for the fungicide, but the increase in returns from higher yields is more pronounced as grain prices increase.”

For example, at a malting barley price of £180/t, a 1.6-1.9t/ha yield response is worth £288-342/ha, far more than the cost of any fungicide programme. Even at current feed barley prices, the return is over £220/ha before fungicide costs.

In spring barley, where fungicide programmes costs are closer to £40-45/ha, yield responses of 0.7-0.9t/ha would give a return of £126-162/ha.

For those growers who had been cutting back with fungicides, this year should mean a return to two or even three-spray timings or higher rates, Dr Oxley says. “For other growers, who had been using robust programmes, it might not mean increasing the amount of fungicide being used, rather trying the new products to see how they can increase yields and quality.”

 

HGCA barley Recommended List varieties response to fungicides

 

Cassata

Retriever

Concerto

Optic

Market

Winter malt

Winter feed

Spring brewing & malt

Spring brewing & malt

UK treated (t/ha)

8.6

9.3

7.5

6.9

UK untreated (t/ha)

7.0

7.2

6.8

5.8

Value of difference / ha @ £80/t

£128

£168

£56

£88

Value of difference / ha @ £180/t

£288

£342

£126

£162

Two or even three sprays should be the rule in barley crops this spring, Dr Oxley says.

The difference between a one-spray strategy on a resistant variety, such as Amarena, in trials has been 0.5t/ha, while in the susceptible variety Retriever, it rises to 0.9t/ha.

“One spray has been used where growers have been looking to cut back on fungicides, or on mixed farms where barley tends not to be the priority.”

Opting for one spray means using a variety resistant to the main disease threats in the local region is a must, with the timing varying from the onset of disease at GS30-32 to GS37-39 in the absence of disease.

But a single spray strategy tends to leave some diseases uncovered, particularly later diseases such as ramularia or rust, if applied early.

“Two sprays are the best approach, and will give optimum disease control, yield and quality in most situations.”

Timing of two sprays is usually GS31-32 and GS45-49 in winter crops, and GS25-30 and GS45-49 in spring crops.

But if there is disease, usually rhynchosporium, coming into spring, then it can also be worthwhile spraying a T0 clean-up spray in winter crops before T1, Dr Oxley suggests.

“Since 2004, T0 sprays have given an extra 0.2t/ha on average. In the past two years the responses have actually been higher, although I’m not really sure why.

“But by managing disease early, you’re in control at GS31-32, and can save on eradicant activity at T1.

“Typically I would suggest using a Kayak (cyprodinil) + Torch (spiroxamine) mix at T0. It is a jack of all trades, master of none, but I would avoid using a triazole or SDHI at that timing as I am twitchy about using a triazole three times in a programme for resistance management reasons.”