These studies have shown that 2,4-D is rapidly degraded in forest litter and that the rate of degradation varies with the type of litter, herbicide formulation and the presence of DDT. The degradation of 2,4-D varies slightly in litter from different vegetation types when incubated under similar environmental conditions. Greater variation in herbicide degradation rates may be expected in the field; but this will be due primarily to differences in the site microenvironment, rather than inherent differences in the litter.Various formulations of 2,4-D are degraded at different rates in forest litter although we believe this to be more a function of constituents of formulation than a direct effect of the technical acid, salt or ester.Finally, these experiments have shown that up to 4 gallons per acre of diesel oil has little or no effect on the decomposition of 2,4-D isooctyl ester, while 1 lb./A. of DDT appears to stimulate herbicide degradation.