Mildew: Should you spray…no

Ground conditions are in good order and as a result many tillage farmers are wondering should they be making use of the opportunity to travel on winter sown crops.

Many winter barley crops have visible signs of mildew and while it may look unsightly it is not going to impact on yields. Spraying for mildew at this time of the year will add to costs with little, if any, return.

Teagasc research shows little or no yield response to fungicides before late-tillering. Cold weather in the coming days should also help to control any disease present.

AgriLand spoke to Teagasc tillage specialist Shay Phelan on the subject.

“On average, tiller numbers on most crops are higher than normal at the moment. They’re at about 1,000 shoots/m² in a lot of cases, so even if there is a bit of tiller death from disease or maybe a lack of nitrogen, crops have the capacity to cope with those problems at the minute.

“There’s no response from any fungicide before late-tillering and we’re a long way from that now. We’re six weeks away. It’s too early.

It’s adding expense to crops that are going to be more expensive to grow this year anyway.

“Fertiliser price has gone up and the likelihood is that the price of grain might not be as high as it was last year, so farmers have to cut their cloth to measure.”


“Farmers shouldn’t be panicking. They should follow the normal guidelines in terms of fertiliser as well.

There’s no point in going out with nitrogen at this time of the year.

With a cold spell due in the coming days farmers should also hold back on phosphorus (P) and potassium (K) applications.

“It’s probably time to put the sprayers and fertiliser spreaders away for a few weeks,” Shay added.


Many farmers have also been wondering whether or not to spray for aphids. The last count from unsprayed winter barley in Teagasc Oak Park – in the second week of January – showed 21.8 aphids/m².

Crops that were untreated for aphids or may have been due a second application – such as late-September sown winter barley which may have been treated with Redigo Deter, but did not get an aphicide which was due in November – may be sprayed now.

Mid-October sown crops treated with Redigo Deter should not need an aphicide now. Late-sown crops which were not treated may be treated now.

“There are crops out there that were due to get an aphicide in late-November or December. In those cases I would say yes [apply an aphicide], but I wouldn’t be going out over and above my normal programme,” Shay concluded.