Economic Threshold for Wild Radish (Raphanus raphanistrum L.) Control in Wheat Fields

Authors: ÖZHAN BOZ

Abstract: Field experiments were conducted in Aydın province in 1998 and 1999 to determine the economic threshold (ET) using florasulam + flumetsulam, 2,4-D amine, thifensulfuron methyl + tribenuron-methyl, and tribenuron-methyl for wild radish (Raphanus raphanistrum L.) in wheat. The effect of wild radish density (1, 2, 4, 8 and 16 plants m^{-2}) on wheat yield was investigated using an adjacent plot design with 4 fields. For each weed density, yield was compared with that in the adjacent weed-free control plot. The grain yield in wild radish-free wheat was 4079 kg ha^{-1} in 1998, 4369 kg ha^{-1} in 1999 and 4224 kg ha^{-1} averaged over the 2 years. Results over the 2 years showed that the ET of wild radish in wheat varied from 1.8 to 2.0 plants m^{-2} depending on the herbicide applied. The lowest ET value was calculated for 2,4-D amine and the highest for florasulam + flumetsulam. It is therefore concluded that wild radish in wheat should be controlled by herbicides if the density is between 1.8 and 2.0 plants m^{-2}. Below this level, a certain amount of damage and the presence of weeds can be tolerated, thus minimizing herbicide use.

Keywords: Wild radish (Raphanus raphanistrum), economic threshold, wheat (Triticum aestivum), florasulam + flumetsulam, 2,4-D amine, thifensulfuron methyl + tribenuron-methyl, tribenuron-methyl

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