Efficacy of foramsulfuron + thiencarbazone-methyl towards different development stages of weed species in sugar beet cultivation

Abstract

The currently available weed control system in sugar beet cultivation has low flexibility due to the necessity of applications at the cotyledon stage of the weeds. The aim of the present study was to evaluate a new herbicide providing more flexibility in terms of application time. In 2013 and 2014, efficacy of an ALS-inhibiting herbicide (foramsulfuron + thiencarbazone-methyl) was evaluated in six field trials in Germany. Sugar beet varieties not sensitive to ALS-inhibiting herbicides are currently in the breeding process. The herbicide was tested on five weed species in different development stages (later than cotyledon stage). In the trials, only weeds but no sugar beet were sown. The herbicide was applied with three dosages at five development stages of the weeds. Efficacy towards Brassica napusL. and Galium aparineL. was nearly 100%. Efficacy towards Chenopodium albumL., Matricaria chamomillaL. and Polygonum convolvulusL. was reduced due to unfavorable weather conditions and with decreasing dosages and increasing development stages. Efficacy was lowest in case of Chenopodium album being close to 95% at BBCH 14 and 16 with 0.50L/ha and 1.00L/ha, respectively. It was thus concluded that the herbicide can be applied later than at cotyledon stage. This implies more flexibility of application timing than current herbicides. To develop a comprehensive evaluation of the weed control system, further studies regarding selectivity, duration of efficacy and resistance risks are necessary.

Duration of Soil Activity of Foramsulfuron Plus Thiencarbazone-methyl Applied to Weed Species Typical of Sugar Beet Cultivation

“…As the duration of soil activity of F/T was more than 10 to 20 DAA, the treatment interval between two applications in practical weed control could be prolonged, and the number of herbicide treatments might decrease in comparison with classic herbicides. A further aspect of evaluating weed control systems is application timing, which was determined by Wendt et al (2016) showed that 4- to 6-leaf stage of common lambsquarter is limiting when 25+15 g FSN+TCM ha −1 are applied, complementing the present data on duration of soil activity. Basic determinations and further studies comparing efficacy and selectivity of F/T to classic herbicides are necessary to specify possibilities and limits of the system.…”

“…Flexibility of application timing and efficacy increase by using F/T (Wendt et al 2016). However, there are no data on the effect of environment and dosage on the duration of soil activity of F/T or on the duration itself.…”

Effect of the Time of Herbicide Application and the Properties of the Spray Solution on the Efficacy of Weed Control in Maize (Zea mays L.) Cultivation

“…Additionally, it reduces their deposition in soil [73]. This technology is already well known in the cultivation of sugar beet [74]. Currently, guidelines have been introduced that place great importance on reducing the amount of chemical preparations used in agriculture [75].…”

Selectivity of foramsulfuron + thiencarbazone‐methyl and classic herbicides in sensitive and non‐sensitive sugar beet genotypes

“…Moreover, the use of F + T could simplify weed control by applying a lower number of a.i.s than in the classic strategy. All benefits, including control of weedy crops (Wegener et al ., ) or increased flexibility in application timing due to high efficacy (Wendt et al ., , ), contrast with the risks of weed resistance and/or gene flow (Kudsk & Streibig, ). Thus, all agricultural measures have to be co‐ordinated throughout the whole crop rotation to minimise potential risks and to reach the full potential of systems with non‐sensitive crops and complementary herbicides.…”

“…A new herbicide for sugar beet cultivation containing the ALS‐inhibitors foramsulfuron and thiencarbazone‐methyl – referred to in the following text as ‘F + T’ – is currently being reviewed for EU‐wide approval (KWS SAAT SE, ). Compared with classic herbicides, applications of F + T can start later (beyond the cotyledon stage of the weeds) and the duration of soil activity is longer (Santel, ; Wendt et al ., , ).…”