The cereal acreage in the ground to date is the highest seen for some time but the recent heavy rainfall has slowed down winter wheat drilling and autumn herbicide application. Slug populations were high throughout the summer and remain so, posing a threat to all crops especially with the current mild damp conditions. Early drilling of winter wheat dramatically increases the risk of take-all following cereal situations. Therefore a seed treatment is advisable. BYDV is a disease carried by aphids and passed into the crop when they feed on the young plants as they emerge through the ground – once infected the disease cannot be controlled. Grassy stubbles and volunteer cereal plants act as host plants for aphids. If a seed treatment has not been applied an application of Sumi-Alpha should be applied from the two leaf stage of the crop.
Annual meadow grass is the main target weed in NI as this weed is the most damaging to yield in all cereal crops. The key to good herbicide control is early timing – before or soon after emergence of the crop. This season with the dry warm conditions pre-em products have not performed as well as expected. Residual herbicide product persistency depends very much on damp soils and cooler temperatures. Scorch has also been an issue with high soil and air temperatures in some crops this autumn.
The last two seasons have enabled us to learn more about the autumn herbicides when used beyond their recommended timing. After two very wet autumns, much of the flufenacet in CRYSTAL and chlortoluron(CTU) in BUCKLER was applied well after the optimum timing. Crystal applied onto barley crops at the 3-4 lt rate per ha performed extremely well on well tillered annual meadow grass (AMG). The inclusion of BUCKLER in the mix will control larger AMG but there is varietal restriction. Sempra has been widely used this autumn in mix with Crystal to strengthen the spectrum of BLW control where weeds are through the ground. Most of the herbicides that are effective on AMG are not safe on oats, making grass weed control in this crop particularly difficult. In recent years LEXUS CLASS has been the principle product used and does a reasonable job when conditions and timings are optimal. SUMIMAX is now another alternative but is an off label approval(EAMU) for use on winter oats. It gives improved AMG activity over LEXUS CLASS and has excellent broad spectrum BLW activity including groundsel and fumitory but must be used pre-emergence of the crop. Othello will be widely used again this spring onto winter wheat crops. In known deficient soils, manganese should be applied during November. Treatment of the condition before deficiency symptoms are seen will mean stronger healthier plants going through to spring.