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

摘要

Field experiments were conducted in Ayd?n 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.