Evaluation of some herbicides for management of resistant littleseed canarygrass (Phalaris minor retz.)
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Date
2009
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CCSHAU
Abstract
Littleseed canarygrass (Phalaris minor Retz.) is a major weed in wheat
fields, and has developed resistance to the commonly used herbicide
isoproturon. Some reports of evolution of cross resistance against
fenoxaprop-p-ethyl have also appeared. This study explores the potential use of
fenoxaprop-p-ethyl, clodinafop, pinoxaden and ready mix formulation of
sulfosulfuron plus metsulfuron (‘Total’), as post-emergence herbicides to
control resistant littleseed canarygrass in wheat(Triticum aestivum L.) and
investigate the mechanism of evolution of cross resistance to fenoxaprop in
P.minor. Greenhouse studies were carried out to determine the phytotoxicity of
these herbicides in relation to percent mortality, plant height, fresh plant
biomass, dry plant biomass, chlorophyll and carotenoid content and leaf
membrane injury on littleseed canarygrass and wheat. These experiments were
conducted in green house unit, Department of Agronomy, CCS HAU, Hisar
(India). Resistant biotypes of Phalaris minor were collected from different
locations of Haryana during 2007-08. Seven biotypes of P.minor from
HAU-Hisar, Uchana, Ambala, Nangla, Chanarthal-1, Chanarthal-2 and
Chanarthal-3, were raised along with wheat (PBW- 343) in pots. Herbicides
(0-240 g ha-1 fenoxaprop, 0-60 g ha-1 clodinafop, 0-120 g ha-1 pinoxaden,
0-80 g ha-1 ‘Total’) were sprayed 35 DAS. Application of fenoxaprop 120 g
ha-1, clodinafop 60 g ha-1, pinoxaden 60 g ha-1, provided control of biotypes
from HAU-Hisar, Uchana, Ambala and Nangla but not from Chanarthal.
However, application of pinoxaden 120 g ha-1 and ready mix formulation of
sulfosulfuron plus metsulfuron 80 g ha-1 provided complete control of all
biotypes of P.minor. Same situation was observed in laboratory experiments. Of
the 7 biotypes studied, these were classified as sensitive (HAU-Hisar and
Ambala), partially resistant (Uchana and Nangla) and resistant types
(Chanarthal-1, Chanarthal-2 and Chanarthal-3). Dose response curves of
decline in fresh weight against herbicide doze provided good indication of the
resistance in various biotypes. GR50 values of the populations tested against
fenoxaprop were in the range of 80 - >240 g ha-1, against clodinafop 30->60 g
ha-1, against pinoxaden 10-120 g ha-1 and against ‘Total’ was 20 - > 80 g
ha-1. This is supported by pigment retention tests and ion efflux tests. Pigment
retention (chl-a, chl-b and carotenoid) was lesser in susceptible biotypes and
more in resistant biotypes after herbicide spray. Ion efflux was also more in
susceptible biotypes as compared to resistant biotypes. Experiment on
mechanism of evolution of resistance to fenoxaprop is indicative of the fact that
there is lesser involvement of detoxification mechanism pointing towards target
site alteration.
Description
Keywords
Wheats, Herbicides, Weeds, Planting, Chlorophylls, Biological phenomena, Crops, Pesticide resistance, Organic compounds, Byproducts