Influence of soil fumigation on 2,4-D and dicamba carryover in fresh market tomato

Two field studies were conducted to evaluate the effect of soil fumigation on the soil persistence of 2,4-D and dicamba residues and their effect on growth and yield of polyethylene-mulched fresh market tomato (Lycopersicon esculentum Mill.). In both trials, treatments consisted of combinations of dicamba and 2,4-D doses applied on non-fumigated and methyl bromide plus chloropicrin-treated plots. Results showed that dicamba injury was greater than that caused by 2,4-D. The highest herbicide injury and crop yield losses occurred in fumigated than in the non-fumigated soil, which could be due to depletion of the population of microorganisms capable of degrading the herbicides.