Take action when slugs become evident
Published 21/09/2010 | 05:00
This year's harvest has a long tail in the northeast, with a sizeable amount of spring wheat, spring oilseed rape and beans impatiently waiting for the cutter-bar. With short days and heavy dew, any opportunity to complete the harvest should be taken. It's still not time to panic, however, as it's relatively early and the huge harvesting capacity available will come to bear once the weather turns favourable to wrap up the harvest.
Oilseed rape crops have got off to a great start. Most crops were sown in good time, into perfect seedbeds and have a herbicide applied. Volunteer cereals are getting established in some fields, particularly along headlands. A low-rate graminicide should be applied sooner rather than later to avoid competition and a refuge for slugs. All crops should be monitored closely for slug activity and action taken as soon as activity is noticed.
Early sown wheat can be considered from now on in as non-take-all risk situations. The benefits of early sowing include potential for higher yield, spreading out the workload, an opportunity to reduce seed costs from low seed rates, higher soil nitrogen uptake which may reduce chemical nitrogen requirement and reduced potential for nitrogen leaching.
This can be especially important where soil nitrogen reserves are high, for example after a break crop. On the negative side, early sowing can increase fungicide and growth regulator costs, increase take-all risk and can result in rapid crop development which can come out of sync with the season.
For example, a crop may end up at growth stage 30 in January, or become infected with disease early on, requiring high levels of fungicide use for the remainder of the season.
The two most important management tools for early sowing of wheat are variety choice and seeding rate. Choose varieties that are slow to develop, but independent information from within Ireland is scant and grower experience is the main source of information. Current varieties that have been used for early sowing are Sahara, Alchemy or JB Diego, but seed availability is an issue.
Very low seed rates are required, the main purpose being that the crop can spend the autumn tillering and covering the available ground rather than racing through developmental stages to develop out of sync with the season. In this context st/ac is a useless parameter and seed should be sown to seeds/m2.