The College of Agriculture, Food and Rural Affairs (CAFRE) has just published a crops update for Northern Ireland.
It relates the continuing impact of the poor weather on winter cereals, while also reflecting on the 2024 spring planting opportunities for grain and potato growers
Weather conditions permitting, growers should aim to apply the second nitrogen (N) dressing by early stem extension.
Crops should also be inspected for recently emerged broad leaved weeds, and top-up herbicide should be applied as temperatures warm up.
It is important that farmers observe product labels for latest application timings, sequences with other herbicides and approved tank mixes with other products.
Disease control
In winter barley, T1 timing aims to maintain tiller numbers. In thinner or later drilled crops, disease pressure should be lower than early drilled thicker crops, so, growers should match fungicide rate to yield potential.
For best control of the main yield robbing barley diseases – rhynchosporium, net blotch and ramularia, growers should use a mixture of active ingredients, rather than single active ingredients.
CAFRE crops specialists are advising arable farmers to consult their BASIS-registered agronomist for advice on effective product combinations and application rates.
Ramularia is difficult to manage, particularly in crops under stress.
Teagasc trials on ramularia show that both prothioconazole and mefentrifluconazole perform consistently better than other leading actives.
In winter wheat, protecting leaf 3 at T1 (GS32-33) and flag leaf at T2 (GS39) are key spray timings for controlling septoria.
Mixtures containing active ingredients, such as mefentrifluconazole (revysol) or fenpicoxamid (inatreq) are recommended.
They give the highest levels of activity, but at a cost which is best justified at T2 and where disease pressure is high.
Agricultural and Horticultural Development Board (AHDB) trials on yellow rust show benzovindiflupyr and prothioconazole (elatus era) are particularly effective, but all good mixtures perform well.
Folpet should be included as a partner in mixes to protect other fungicide groups, as its inclusion slows the pace of disease resistance developing in both wheat and barley.
Spring crops
According to CAFRE advisors, as April progresses, growers should gradually increase seed rate up to 400 seeds/m2 for spring barley. They should also plan to treat weeds in all sown crops as soon as possible.
Pre-emergence herbicides in spring cereals can help manage resistant broad leaved weeds, such as chickweed and to target problem annual meadow grass.
Once planted, protein crops grow and develop quite slowly for the first few weeks after emergence. This means that weed control is the most important target that growers can achieve to ensure a good yield in peas and bean crops.
Pre-emergence herbicide application gives the best control of broad leaved weeds, as post-emergent options are limited.
It is a case of not covering a wide spectrum of weeds, as these products can be harsh on the growing crop.
If grass weeds or cereal volunteers appear, a graminicide (herbicide specifically targeting grass and cereals) can be applied.
The optimal graminicide timing is usually when most grass weeds have emerged, before the crop canopy closes in and before the latest safe application.
Again, growers should consult product labels and get agronomist advice if they are unsure of timing to avoid crop damage.
Potatoes
Pre-sprouting systems must deliver adequate temperature, ventilation and light to control sprout growth and to protect against frost.
A range of pre-emergence products offer good weed control in potatoes, however, for best results these need to be applied as soon as possible after planting.
If the window for pre-emergence herbicides has passed, contact herbicides such as carfentrazone (shark) are a good option.
Late plantings will delay the final harvest of maincrop potatoes. If planting is delayed, a rule of thumb is to reduce the N rate by 1.0kg/ha/day after planned planting date.
Late N applications will keep the canopy greener for longer, holding back the start of harvest at the other end of the season.
