Resistance of Raphanus raphanistrum to the herbicide metsulfuron-methyl

Abstract

-The ALS-inhibiting herbicides, especially metsulfuron-methyl, are widely used for weed control, mainly wheat and barley in southern Brazil. Raphanus raphanistrum is a major weed of winter crops. However, in recent years, R. raphanistrum, after being treated with metsulfuron, has shown no symptoms of toxicity, possibly due to herbicide resistance. Aiming to evaluate the existence of R. raphanistrum biotypes resistant to metsulfuron, an experiment was conducted in a greenhouse, in a completely randomized design with four replications. The plots consisted of pots with six plants. The treatments consisted of the interaction of resistant R. raphanistrum (biotype R) and susceptible R. raphanistrum (biotypes S) with ten doses of the herbicide (0.0; 0.6; 1.2; 2.4; 4.8; 9.6; 19.2; 38.4; 76.8 and 153.6 g i.a. ha -1 ). The application of the test herbicides occurred when the crop was at the stage of 3 to 4 true leaves. The variables analyzed were control and dry matter accumulation. Statistical analysis of dose-response curves was performed by non linear regression. Biotype S was susceptible to the herbicide even at doses below the recommended. Biotype R was insensitive to the herbicide obtaining values of resistance factor (F) higher than 85. The dose-response curve confirmed the existence of R. raphanistrum biotypes with high level of resistance to metsulfuron-methyl.Keywords: acetolactate synthase, dose-response, weed, resistance factor. (0,0; 0,6; 1,2; 2,4; 4,8; 9,6; 19,2; 38,4; 76,8; e 153,6 g i.a. ha -1 Palavras-chave: acetolactato sintase, dose-resposta, planta daninha, fator de resistência. RESUMO -Os herbicidas inibidores de ALS, especialmente metsulfuron metílico, são amplamente utilizados para controle de plantas daninhas, principalmente em trigo e cevada, no sul do Brasil. Raphanus raphanistrum é planta daninha comum em culturas de inverno. No entanto, nos últimos anos, plantas de R. raphanistrum têm sobrevivido após o tratamento com o herbicida. Com o objetivo de avaliar a existência de biótipos de R. raphanistrum resistentes ao herbicida metsulfuron, foi conduzido experimento em casa de vegetação, em delineamento inteiramente casualizado com quatro repetições. As unidades experimentais consistiram de vasos contendo seis plantas cada. Os tratamentos constaram da interação de R. raphanistrum resistente (biótipo R) e suscetível (biótipo S) com dez doses crescentes do herbicida

COMPETITIVE ABILITY OF WHEAT IN ASSOCIATION WITH BIOTYPES OF Raphanus raphanistrum L. RESISTANT AND SUSCEPTIBLE TO ALS-INHIBITOR HERBICIDES

“…After confirming resistance to ALS inhibitors (Costa;Rizzardi, 2014), the seeds of these plants constituted the resistant population of Raphanus raphanistrum (R biotype). To obtain the susceptible population (S biotype), seeds were collected from plants of R. raphanistrum in northern Paraná, near the collection site of the resistant population, where there was no history of application of ALS inhibitors herbicides.…”

Broad resistance to acetohydroxyacid-synthase-inhibiting herbicides in feral radish (Raphanus sativus L.) populations from Argentina

“…In the last decade, the number of herbicide‐resistant biotypes of Raphanus spp. has increased, including those of R. raphanistrum with cross‐resistance to acetohydroxyacid synthase (AHAS)‐inhibiting herbicides from Australia, South Africa and Brazil and with multiple resistance across several modes of action from Western Australia . A biotype of feral radish with herbicide resistance to AHAS‐inhibiting herbicides was reported in Brazil, Chile and Argentina …”

Reproduction of Pratylenchus zeae on Weeds

“…In this regard, it is important to emphasize that species like L. multiflorum and R. raphanistrum are often used as forage and ground cover plants in integrated crop-livestock and no-till farming systems, respectively (Machado and Assis, 2010). Furthermore, in the last crop seasons, ryegrass has exhibited resistance to the herbicides used in its control, causing harvest losses in winter and spring-summer cultures and enabling its perpetuation in the area (Roman et al, 2004;Costa and Rizzardi, 2014). In this scenario, the use of these plant species in the cultivation systems or their presence as invasive plants should be maintained only in areas not contaminated with this parasite to prevent its proliferation and damages to subsequent crops.…”