Tillage Farm Management Notes: 01/06/2010
Controlling Weeds in Maize and Sugar Beet Crops
Many livestock farmers have turned to maize to deliver a portion of their winter feed requirements, others; particularly in the traditional sugar beet growing areas continue to rely on both sugar beet and fodder beet to feed stock over the winter. The indications are that the area of maize grown in the country may be back slightly this year at around 22,000 hectares, but more producers seem to favouring sowing under plastic this year. Controlling weeds in both maize and beet crops present their own unique challenges.
Maize crops are emerging through plastic and growing well at the moment while later sown crops in the open are just after emerging. Controlling weeds and making sure crops have the required trace elements is the next big task for those with maize. These should ideally be done in the next couple of weeks. The main post-emergence product used by farmers with maize not under plastic is likely to be Calaris. A rate of 1 - 1.5 litres per hectare should be sufficient. To get the best residual results this should go on at the 2 – 4 leaf stage, which will give up to six weeks residual control and allow the crops to cover in.
Make sure there is adequate manganese and zinc to meet crop requirements, if this needs to be addressed now is the best time to apply. Like with any weed control programme, the effectiveness of the spray programme needs to be monitored. There are a few weeds that can cause problems, namely black nightshade, orache and fat hen. These sometimes create difficulties with a second later flush of growth emerging. A herbicide like Bromoxynil could be used at a rate of 1.5 - 2 litres per hectare to control any re-emerging weeds in 2 – 3 weeks following the first spray. Difficult weeds like scotch, thistle or volunteer potatoes will need to be treated with a specialist herbicide like Titus or Fluroxypyr. Dupont have a new post-emergence herbicide out this year called Accent. Its active ingredient is nicosulfuron and it claims to have good control of grasses, wild oats and some other broadleaved weeds such as cleavers, redshank and brassicas, but it has little residual effect so it needs to be used in conjunction with Calaris or Callisto.
Weeds in Fodder Beet
Weed control is the main priority in beet crops, having been sown in excellent conditions, in general, this year. A combination of herbicides and mechanical means are usually deployed depending on what suits individual circumstances and machinery available. Keeping weeds in check early on is critical to the overall performance of the crop.
A very popular T1 for weed control is Debut (30g/Ha)+Betanal Expert (0.50L/Ha) +Goltix 0.5Kg/Ha + Methylated rape oil Eg Fortune, Diamond Toil, This is a good all round T1, maybe poorer on mayweed, fools parsley and bindweed. Replace the goltix with 0.5L/ha of Venzar in that situation but may lose some effect on pansy, fat hen and orache.
Goalpost/ Wizard/ Expert and Goltix are the main herbicides favoured by farmers for the T2 on beet. Goltix helps to give good residual persistence for weed control for the season.
Goalpost 3.0L/ha or Betanal Expert 1.5L/ha + Goltix,Beetrix 1.5Kg/ha +oil. This is a very good follow-on to the T1 where no charlock is present. Target weeds would be fat hen, orache and marigold.
The timings of the T1 and T2 sprays should be targeted to be up to 14 days apart to give best results. If midday temperatures continue to remain high, be be careful not to scorch the crops.
