Growth and development of Cirsium arvense in relation to herbicide dose, timing of herbicide application and crop presence

Abstract

The aim of this study is to assess control effects of 2-methyl-4-chlorophenoxyacetic acid (MCPA) dosage, application timing and crop presence on the weed Cirsium arvense. Swedish farmers are recommended to control C. arvense chemically when most shoots are 10-20 cm tall, and mechanically at the compensation point (CP). Recent studies have shown that the CP occurs before shoots reach the three-leaf stage. We hypothesised that (i) herbicide application near the three-leaf stage gives the strongest control, (ii) crop presence increases herbicide effects, and (iii) a 50% herbicide dose gives the same effect as 100%. Treatments of the pot experiment consisted of MCPA 750; 0%, 50% and 100% of the recommended dose applied at leaf stages 3-8, with and without barley. The strongest control was obtained at four leaves and a maximum shoot height of 13 cm, using the recommended dose and with spring barley. In a field population, a maximum shoot height of 13 cm corresponded to a medium height of 6 cm. The 50% dose gave poorer control. Spraying with the recommended dose at the four-leaf stage reduced the development of C. arvense most effectively. Based on this, we recommend that herbicide spraying should be performed at earlier leaf stages/median heights than previously recommended.

Keywords

Biomass production; Canada thistle; MCPA; phenology; spring barley; weed control

Published in

Acta Agriculturae Scandinavica, Section B - Soil and Plant Science
2019, volume: 69, number: 3, pages: 189-198
Publisher: TAYLOR & FRANCIS AS

SLU Authors

• Tavaziva, Varwi Jacob

  • Department of Crop Production Ecology, Swedish University of Agricultural Sciences
    

• Verwijst, Theo

  • Department of Crop Production Ecology, Swedish University of Agricultural Sciences
    

• Lundkvist, Anneli

  • Department of Crop Production Ecology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network

UKÄ Subject classification

Agricultural Science

Publication identifier

• DOI: https://doi.org/10.1080/09064710.2018.1526964

Permanent link to this page (URI)

https://res.slu.se/id/publ/98158