Weed Science (2005) 53, 290-295

Chanya Maneechote, Somsak Samanwong, Xiao-Qi Zhang and Stephen B. Powles (2005)
Resistance to ACCase-inhibiting herbicides in sprangletop (Leptochloa chinensis)
Weed Science 53 (3), 290-295
Abstract: This study reports evolved resistance to fenoxaprop-P in a population of sprangletop from a rice field in Thailand (BLC1). After eight applications of fenoxaprop-P, the herbicide appeared no longer effective. To confirm herbicide resistance in the BLC1 population, three experiments were conducted. First, glasshouse experiments revealed that the BLC1 population survived 600 g ai ha⁻¹ of fenoxaprop-P without visual injury. Second, the BLC1 population was treated with fenoxaprop-P and other acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicides (quizalofop-P, cyhalofop-butyl, and profoxydim) under field conditions; BLC1 exhibited resistance to all of these herbicides. Third, seeds of susceptible SLC1 and resistant BLC1 were germinated on 0.6% (v/v) agar across a range of herbicide concentrations. The resistant BLC1 population exhibited 61-, 44-, 9- and 8-fold resistance to fenoxaprop-P, cyhalofop, quizalofop-P, and profoxydim, respectively, compared with a susceptible SLC1 population. At the enzyme level, ACCase from the resistant BLC1 exhibited 30, 24, 11, 4, and 5 times resistance to fenoxaprop, cyhalofop-butyl, haloxyfop, clethodim, and cycloxydim, respectively. The spectrum of resistance at the whole plant level correlated well with resistance at the ACCase level. Hence, the mechanism of resistance to ACCase-inhibiting herbicides in this biotype of sprangletop is a herbicide-resistant ACCase. The specific mutation(s) of the ACCase gene that endows resistance in this population remains to be investigated.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Stephen B. Powles

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Leptochloa chinensis (weed)	Rice (Oryza)	Thailand