Resistance of Wild Radish (Raphanus raphanistrum) to Acetolactate Synthase-Inhibiting Herbicides in the Western Australia Wheat Belt¹

Abstract

Of 78 biotypes of wild radish (Raphanus raphanistrum) collected from Western Australia (WA), 42% were resistant and 14% intermediate to acetolactate synthase (ALS)-inhibiting herbicides. Based on the LD50 and GR50 ratios, the resistant biotype K96071 was 81-fold more resistant to chlorsulfuron and 114- to 116-fold more resistant to metosulam than the susceptible biotype K96041. More resistant biotypes were found in northern zones than in southern zones of WA. Resistant biotypes evolved after five applications of chlorsulfuron in a predominantly cereal–lupin rotation. Where resistant biotypes were found, ALS-inhibiting herbicides were not rotated with herbicides with different modes of action as frequently as in fields with susceptible biotypes. Cross-resistance to chlorsulfuron and metosulam was found in the resistant biotypes even though only 15% of the 78 biotypes were exposed to two applications of metosulam over a 10-yr period. All 78 biotypes were effectively controlled by simazine and 2,4-D amine.

The biology of Canadian weeds. 132. Raphanus raphanistrum L.

“…In an Australian weed survey in winter crops, R. raphanistrum was one of the three most widespread and abundant weeds, and the one whose spread was the most difficult to control, particularly in the southern and western regions where herbicide resistance has developed (See Section 11) (Alemseged et al 2001). Densities as low as 10 wild radish plants m -2 reduced wheat yields by up to 20% (Reeves et al 1981), with up to 50% reduction at densities of 80 wild radish plants m -2 (Hashem et al 2001a). The initial flush of germination followed by sporadic germination throughout a long growing season contributes to herbicide control problems in Australia (Donaldson 1986).…”

“…These primarily include biotypes resistant to acetolactate synthase (ALS)-inhibitors and/or resistant to photosystem II-inhibitors (triazines). ALSinhibitor R biotypes were first detected in 1997 after five applications of chlorsulfuron in a predominantly cereal to narrow-leafed lupin rotation (Hashem et al 2001a). By 1999, about 21% of wild radish populations in the western Australian wheat belt were chlorsulfuron-R (Walsh et al 2001), with about 13% of these cross-resistant to imidazolinones (another ALS-inhibitor) (Hashem and Dhammu 2002).…”

“…ALS-inhibitor R wild radish biotypes were effectively controlled (100% killed) by simazine at 0.50 kg ha -1 applied pre-emergence and 2,4-D amine at 0.50 kg ha -1 applied post-emergence (Hashem et al 2001a). Triazine-resistant wild radish biotypes were killed at the 2-3 leaf stage by 2,4-D at 0.50 kg ha -1 , glyphosate at 0.46 kg ha -1 , and paraquat at 0.25 kg ha -1 , and well-controlled by chlorsulfuron at 0.015 kg ha -1 (86-95% control), metosulam at 0.05 kg ha -1 (85-95% control) and diflufenican at 0.50 kg ha -1 (97-100% control) (Hashem et al 2001b).…”

Efficacy of Herbicides in Non-Puddled Transplanted Rice Under Conservation Agriculture Systems and Their Effect on Establishment of the Succeeding Crops

“…Conversely, other reports confirmed that application of pre-emergence and post-emergence herbicides ensured continuous effective control of weed species that emerged in several flushes and provided better yield over manual weeding even under minimum tillage practice [27,28]. But, the repeated use of herbicide with the same mode of action may leads to develop quick herbicide resistance in weeds which will make weed control more difficult [29][30][31][32]. Therefore, rotation of herbicides with different modes of action would benefit weed management in the longer term and minimise risks for development of herbicide resistance in weeds.…”

Resistance of Raphanus raphanistrum to the herbicide metsulfuron-methyl

“…Now the susceptible biotype was controlled in 70 to 100%, with doses of 15 and 60 g i.a. ha -1 , respectively (Hashem et al, 2001). …”