Control possibilities of Apera spica-venti (L.) P.Beauv. in winter wheat with autumn and spring applications of herbicides in Latvia

This paper presents results on weed control and yield responses in winter wheat grown after winter oilseed rape and after winter wheat, using data from field trials with a range of herbicides registered for use in Latvia that were applied either in the autumn or in the spring. Apera spica-venti was the dominant weed in these trials, accounting for 70-80% of the total weed biomass. Spring application of herbicides did not provide good control of Apera spica-venti up to harvest time: the infestation at application time was more than 140 plants per m2. Autumn application of appropriate herbicides gave satisfactory control of Apera spica-venti up to harvest time in the following year. All herbicide treatments significantly increased crop yield but the autumn applications gave significantly greater increases than nearly all spring applications.