Yellow nutsedge (Cyperus esculentus L.) is a perennial herbaceous member of the sedge family (Cyperaceae). It has a high potential to reproduce vegetatively through tubers which can survive the winter period. It also produces abundant seeds. Among the herbicides available for weed control in Italian rice crop, only two acetolactate synthase (ALS) inhibitors, i.e. halosulfuron and azimsulfuron applied in post-emergence, are effective to control C. esculentus. Other chemical options are less effective. The high reliance on ALS inhibitors to control other weed rice species has increased the selection pressure and in recent years rice growers have reported failure to control nutsedge. This study was conducted to confirm the suspected resistant status of two C. esculentus populations collected in rice fields from north-western Italy. Tubers from C. esculentus plants that had survived a treatment as well as from a susceptible population were collected. A whole plant bioassay was carried out in a greenhouse. Seedlings were treated at the 3-4 leaf stage with halosulfuron (30 g p.a./ha) and azimsulfuron (22.5 g p.a./ha) at the recommended label rate. Herbicides were applied with recommended surfactants, using a precision bench sprayer delivering 300 L/ha, at a pressure of 215 kPa and a speed of 0.75 m s-1, with a boom equipped with three flat-fan hydraulic nozzles (TeeJet®, 11002). Both populations were found to be highly resistant (more than 80 % survival and biomass) to azimsulfuron and cross resistant to halosulfuron. ALS-resistant C. esculentus is of particular concern because it is one of the few resistant cases which involves a geophyte species with a high reproductive ability, there are no other chemical options available and it can infest other important summer crops. A careful integrated weed management approach is needed to avoid the spread of resistant tubers from field to field through machinery and agronomic practices.
Evidence of Cyperus esculentus resistant to ALS inhibitors in Italian rice fields
Scarabel L;Sattin M
2018
Abstract
Yellow nutsedge (Cyperus esculentus L.) is a perennial herbaceous member of the sedge family (Cyperaceae). It has a high potential to reproduce vegetatively through tubers which can survive the winter period. It also produces abundant seeds. Among the herbicides available for weed control in Italian rice crop, only two acetolactate synthase (ALS) inhibitors, i.e. halosulfuron and azimsulfuron applied in post-emergence, are effective to control C. esculentus. Other chemical options are less effective. The high reliance on ALS inhibitors to control other weed rice species has increased the selection pressure and in recent years rice growers have reported failure to control nutsedge. This study was conducted to confirm the suspected resistant status of two C. esculentus populations collected in rice fields from north-western Italy. Tubers from C. esculentus plants that had survived a treatment as well as from a susceptible population were collected. A whole plant bioassay was carried out in a greenhouse. Seedlings were treated at the 3-4 leaf stage with halosulfuron (30 g p.a./ha) and azimsulfuron (22.5 g p.a./ha) at the recommended label rate. Herbicides were applied with recommended surfactants, using a precision bench sprayer delivering 300 L/ha, at a pressure of 215 kPa and a speed of 0.75 m s-1, with a boom equipped with three flat-fan hydraulic nozzles (TeeJet®, 11002). Both populations were found to be highly resistant (more than 80 % survival and biomass) to azimsulfuron and cross resistant to halosulfuron. ALS-resistant C. esculentus is of particular concern because it is one of the few resistant cases which involves a geophyte species with a high reproductive ability, there are no other chemical options available and it can infest other important summer crops. A careful integrated weed management approach is needed to avoid the spread of resistant tubers from field to field through machinery and agronomic practices.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
