Integrated control of herbicide resistant Lolium rigidum in extensive rainfed crops José Mª Montull, Andreu Taberner

Introduction Rainfed crops in Spain take around ha Yields fluctuate between 1-5 tm/ha of barley There are few available crops for rotation & farmers unknown the return on alternative crops

Introduction In the short term, monocropping seems to have more return In the long term, rotations can have the same or more return: ◦Increase of yields ◦Decreases pests ◦Decresase the cost on plant protection Directive 2009/128/EC establishes the requirement of IPM

Introduction Alternative crops There are two groups of alternative crops: ◦Oilseed crops ◦Pulse crops Broadleaf crops can facilitate grass weeds managing: ◦Late crop sowing ◦Use herbicides with different modes of action ◦Use of “strong” ACCase inhibitors for control NTSR

Introduction Objective The main objective of this paper is to study different alternatives for herbicide- resistant L. Rigidum control in rainfed cereal cropping systems, integrating three different crops in rotation different herbicides approved for each crop.

Material & methods Field located in Calaf (Lleida) (NE Spain) 480mm average annual rainfall Clay-loam soil Difficulty to control Lolium rigidum with herbicides Three crops: Winter wheat, spring barley & spring field pea 5 herbicides per crop & untreated

Material & methods Crop HerbicideActive ingredient Rate (kg o l cp/ha) Aplication time (respect the crop) Winter wheat Untreated0 AurosProsulfocarb 80%409 BBCH CTUClortolurón 50%211 BBCH AtlantisIodosulfuron 0,6%+ mesosulfuron 3%0,513BBCH BroadwayFlorasulam 2,28% +Pyroxulam 6,83%0,26513BBCH Caliban duoIodosulfurón 1%+propoxicarbazona 16,8%33013BBCH Spring barley Untreated0 CTUClortolurón 50%411BBCH HerbaflexBeflubutamida 8,5%+Isoproturon 50%2,511BBCH AxialPinoxaden 10%0,613BBCH HussarIodosulfuron 5%0,213BBCH Splendor 40Tralkoxidim 40%122BBCH Spring pea Untreated0 AurosProsulfocarb 80%509BBCH MutualImazamox 1,67%+Pendimetalina 25%309BBCH Kerb FloPropizamida 40%1,87513BBCH Fusilade MaxFluazifop-P 12,5%213BBCH Aramo 50Tepraloxidim 5%113BBCH

Material & methods Aplication due with an experimental sprayer pressurised with nitrogen Boom with 4 Hardi ISO LD nozzles 330l/ha of water delivery

Results & discussion Lolium density at harvest in untreated plots

Results & discussion

Results & discussion Lolium Density at harvest

Results & discussion

Conclusions 1. The effect of sowing in late January have been enough to avoid applying herbicides against L. rigidum in barley crop 2. In this test, low efficacy has been achieved with ALS and ACCase inhibitors due resistance to these groups of herbicides 3. Auros and Kerb efficacy was conditioned by the drought at winter in the application time 4. Only Mutual and Auros in spring pea, have been achieved efficaccy up to 90%

Conclusions plants/m2 of L. rigidum in winter wheat justify a treatment for control it plants/m2 of L. rigidum in spring barley not justify a herbicide treatment plants/m2 of L. rigidum in spring pea justify a treatment for controlling it 8. If this field, infested by a Lolium herbicide resistant biotype, it was not economically justified a treatment with an herbicide which the weed has developed resistance. In this case, the best solution has been the crop change.