Effect of Clodinafop-propargyl on Phalaris paradoxa L. (awned canary-grass) in wheat crop

Phalaris paradoxa is problematic weed that decrease considerably wheat crop yields. The aim of this study is to investigate the effect of Clodinafop-propargyl on Phalaris paradoxa infestation in a soft wheat crop. The experimental design was Randomized Complete Block Design (RCBD) with three replications. Each block contained 4 elementary plots, 3 plots of which were treated with three rates of application of Clodinafoppropargyl and one untreated control plot. Observations concerned Percentage of Phalaris paradoxa density reduction and biomass reduction. Results showed that treatments with Clodinafop-propargyl at 60 g/ha and 80 g/ha gave the best control of Phalaris paradoxa infestations recording respectively 96.2% and 98.5% of Phalaris paradoxa density reduction and 95.5% and 99.3% of Phalaris paradoxa dry biomass reduction. Clodinafop-propargyl at 40 g/ha recorded lower efficacies 77.1% and 82.3% respectively on Phalaris paradoxa density reduction, and Phalaris paradoxa dry biomass reduction. Keywords— Phalaris paradoxa, Clodinafop-propargyl, wheat, density, biomass.


INTRODUCTION
Weeds are a major problem on wheat production in Morocco as they compete on water, minerals and sunlight and make harvest operation more difficult (Zimadahl & El Brahli, 1992;Boutahar, 1994;Taleb, 1996;Bouhache, 2007;. Phalaris paradoxa L. (awned canary-grass) belongs to Poaceae botanical Family. It is an annual plant. Upright 20 cm to 1.20 m high (Tanji, 2005). Leaves 10 to 20 cm long and 5 to 10 mm wide. Membrane ligules, 3 to 4 mm long. No auricles. Inflorescence is a compact and rough panicle, sometimes wrapped by the upper leaf, cylindrical, narrowed at the base, 3 to 10 cm long and 1 to 2 cm wide. Palms of the panicle made up of beams of 5 to 7 spikelets (Tanji, 2005). Central spikelets are fertiles, the others steriles. Oval seeds, hairless, shiny, 3 to 4 mm long and 1 to 2 mm wide without chip at the base, usually having 3 long lines on each side. Seedling is hairless, coiled prefoliation. First leaves 5 to 10 cm long and 1 to 2 mm wide. Membrane ligule, 1 to 4 mm. Seed determination makes it easier to recognize the seedling (Tanji, 2005). Plant lying on different types of soil and consumed by animals. Seeds are usually consumed by birds. Clodinafop-propargyl is an herbicide that belongs to Aryloxyphenoxy-propionate 'FOPs' family. It is a systemic herbicide absorbed by leaves to control grasses. It causes inhibition of acetyl CoA carboxylase (ACCase) which is an enzyme that catalyzes the fatty-acid synthesis (Ezzahiri & al., 2017). Clodinafop-propargyl inhibits the ACCase enzyme activity, thus blocking the production of phospholipids necessary for synthesizing the lipid bilayer, which is indispensable for cell structure and function. Phalaris paradoxa decrease considerably cereal yields in Ouazzan region of Morocco. The aim of this study is to compare the effect of three doses of Clodinafop-propargyl on Phalaris paradoxa infestation in a soft wheat crop in the Ouazzan region of Morocco.

II.
MATERIAL AND METHODS A weed control trial was conducted in Ouazzane region of Morocco during 2017-2018 growing season. The experimental design was Randomized Complete Block Design (RCBD) with three replications. The distance between the blocks was 2 meters and the distance between plots was 1 meter. Each block contained 4 elementary plots, 3 plots of which were treated with the postemergence herbicides tested (Table 1) and one untreated control plot. The size of the elementary plots was 2m x 5m (10 m²). Treatments was carried out on January 2, 2018 with a Knapsack herbicide sprayer with nozzle delivering a 3 bar jet. The spray volume per hectare is 200L. Treatments consist on three rates of application of Clodinafop-propargyl (

III. RESULTS AND DISCUSSION Effect on Phalaris paradoxa density reduction
Statistical analysis revealed significant differences between treatments (Table 2). Results in Table 2 showed that the best Phalaris paradoxa density reduction was obtained by Clodinafop-propargyl at 60 g/ha and 80 g/ha recording respectively 96.2% and 98.5% of Phalaris paradoxa density reduction. Clodinafop-propargyl at 40 g/ha showed lower efficacy recoding 77.1 % of Phalaris paradoxa density reduction ( fig. 1).

Effect on Phalaris paradoxa dry biomass reduction
Statistical analysis revealed significant differences between treatments (Table 3). Data in Table 3 indicate that the best Phalaris paradoxa dry biomass reduction was achieved by Clodinafop-propargyl at 60 g/ha and 80 g/ha recording respectively 95.5 % and 99.3% of Phalaris paradoxa dry biomass reduction. Concerning the effect of Clodinafop-propargyl at 40 g/ha, results showed lower efficacy recording 82.3% of Phalaris paradoxa dry biomass reduction ( fig. 2).

IV. CONCLUSION
This study has shown that the herbicide Clodinafoppropargyl at 60 g/ha and 80 g/ha gave the best control of Phalaris paradoxa. Clodinafop-propargyl at 40 g/ha lower control of Phalaris paradoxa. Thus, Clodinafop-propargyl at 60 g/ha can be recommended to farmers in Ouazzane region when Phalaris paradoxa infestation is dominant.