Nowis the time to start looking for areas of poorly controlled grass-weeds. Pastfield history is important but keep a very open mind. This year we have seen patches of great brome appear inpreviously clean fields where cultivation practices changed last autumn.
Judicioustreatment with total herbicides now will prevent a localised problem fromescalating. It is generally too late for selective herbicides, if the problemis resistance they will be a waste of effort anyway.
Grassweeds rarely move far via natural dispersal mechanisms. Being self-pollinated they very muchstick to their own patch. Unfortunately combines and balers are very good at spreading seed arounda field or between fields (contractors can easily spread weeds from farm tofarm). Operators can help byensuring they clean down harvest implements before changing fields. Buying in straw from an unknown sourcefar afield gives weed seeds national mobility.
Mappatches now and keep a year-on-year log. For those so inclined there are free mapping apps for smart phoneswhich will work to around 5m accuracy. One is a free My Maps Editor that will work with your phone’s Googlemaps software, allowing you to drop labelled markers into place where problemareas occur – iPhone version or Android version
Alternatively, costing just £2.99,BASF’s weed identification app has a weed mapping facility – download here
Anotherfree option is Precison Earth which is primarily designed for soil sampling but can easily be used to mark weed infested patches. It’s only available for iPhones –download here
Wehave also been successful in identifying weed areas with satellite imagesshowing chlorophyll content and NVDI. (Normalized DifferenceVegetation Index – a satellite-imaging measureused to assess the amount oflive green vegetation on the ground).
Sorryto bring an air of autumnal grass weed gloom to a fine spring day. Fighting the stuff is a year-round warof attrition and it can’t be conquered with one or two grand seasonal battles.