© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Grass weed management with IPM Denmark MODULE C17

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Know your weeds – grass weeds IPM measures for controlling winter annual grass weeds: A healthy crop rotation Delayed sowing Optimal plant density Focused soil cultivation, including Stale seedbed Stubble cultivation Ploughing Glyphosate before sowing the main crop Optimized use of herbicides IPM means that all plant protection measures have to be used wisely, otherwise problems like resistance may develop rapidly

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY A varied crop rotation will be able prevent grass weeds - But remember economic sustainability! Example of crop rotation suggested by the ENDURE RA2.6 participants for use under northern European conditions on a pig producing farm Alopecurus myosuroides (Black grass) Apera spica- venti (Loose Silky-bent) Examples of grass weeds sensitive to a varied crop rotation Importance of the crop rotation

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY The effect of a varied crop rotation: Plants/m 2 Crop rotation with 50 % cerealsCrop rotation with 75 % cereals No weed control With weed control Broadleaved weeds Apera spica-venti German experiments Importance of the crop rotation

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Early sowing promotes grass weed infestation Amount of Alopecurus myosuroides in winter wheat at harvest as a function of the sowing time Plants/m 2 Early sowing Normal sowing Sowing date

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Amount of Apera spica-venti in a crop rotation with 80 % winter cereals Plants/m 2 PloughedReduced cultivation No weed control 50 % normal doze 25 % normal doze 100 % normal doze Combining soil cultivation and herbicides provides effective control of grass weeds: Soil management and grass weed seeds

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Know your weeds – important differences Effective control is achieved through knowledge of the weed. Grass weedFlowering (1) Preventive measures Alopecurus myosuroides Use the general principles, herbicide resistance is developing rapidly Bromus hordeaceusAvoid stubble cultivation after harvest Bromus sterilisHarrow light, immediately after harvest Apera spica-ventiPloughing before sowing will reduce Apera seed bank Poa trivialisAs Apera spica-venti (1): For climatic conditions similar to the Danish

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Major reduction of seed bank without using herbicides Special case– Bromus sterilis

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Traits of the varieties Use available information about the yield potential, disease resistance etc. 1. Winter hardiness 2. Yield 3. Quality (fodder, grain etc.) 4. Risk of lodging 5. Tolerance towards diseases (varies among species) 6. Competition against weeds Prioritized list for choice of winter cereal variety:

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Chemical weed control Yield increase from chemical weed control Source: The Danish National Field Trials ® 2008 Apera spica-venti Poa annua & Dicot weeds Lolium sp.Dicot weeds

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Chemical weed control Choose the right product for the right job! Use as little as possible but as much as needed Use Decision Support Systems where available, e.g. Crop Protection online: demo&subjectid=1&language=en demo&subjectid=1&language=en It is a challenge to treat fields individually – where large – scale farming is an important parameter, it may e.g. be relevant to think about a basic- and advanced treatment –Divide e.g. the fields in groups according to problem Consider margin and patch spraying in larger scale

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Prevention of resistance Change between products with different modes of action Avoid using Sulfunylurea-products more than once every growing season Change between modes of action This wheat field was in the spring treated with 2 ALS- inhibiting herbicides: 110 g Broadway (florasulam+pyroxulam) and app. 0.1 l Iodosulfuron. Lolium perenne is still growing almost unaffected This wheat field was in the spring treated with 2 ALS- inhibiting herbicides: 110 g Broadway (florasulam+pyroxulam) and app. 0.1 l Iodosulfuron. Lolium perenne is still growing almost unaffected

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Dispersal of grass weed seeds Through machinery –As the farms grow bigger, the machinery has to cover larger areas, and seeds are very likely to be spread Therefore: remember proper hygiene –This means:  Harvest the infested fields last, whenever possible  Clean machinery when leaving an infested field  Keep a stable field margin with perennial herbs, to avoid weed infestations to spread from here

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Evaluation of the effort Before harvest, make a field walk to: –Follow up on the crop protection performed through the season –Plan the strategy for the next season –Make/update the weed map A good result starts with proper planning! Weed map: