Weeds have the greatest impact if uncontrolled after flowering, when the bulbs begin floral initiation.
HDC project BOF 73 looked at herbicide use post-cropping and at alternative persistent residual products to apply in the dormant period to avoid pre-cropping treatments.
Trials were undertaken in a commercial crop of Tamsyn that was in its second year in 2011. In terms of post-cropping treatments, three herbicide tank mixes appeared effective.
Stomp Aqua + Kerb Flo produced little or no damage and while effective against fat-hen, groundsel was not controlled. Wing-P + Barton WG was safe and gave the best weed control. Butryflow + Stomp Aqua appeared very safe and gave some pre-emergence control of groundsel.
In dormant-stage treatments, the product Chikara appeared very safe at the single-dose rate and was the most persistent but also most expensive and is not currently permitted in the presence of a crop or on land to be cropped.
An Intruder + Sencorex SC treatment was effective and safe and similar in cost to the industry standard treatment (Intruder + Linurex 50SC). Jouster and Cadou Star, applied as individual treatments, were safe but less effective.
Tamsyn is an early variety that, in 2011, emerged early after a mild autumn. No other herbicide application would have been required at pre-cropping following any of the residual treatments.
Horticultural Development Company
For details on all HDC activity, visit www.hdc.org.uk.