Furrow-irrigated fields are good hosts to sudden death syndrome (SDS). But the disease doesn't roam all over those fields, say University of Arkansas plant pathologists.
The soilborne fungal disease has been found to be more severe at the upper ends of furrow-irrigated fields where water enters the rows. Very little disease has been found at the lower ends. That's probably because soils at the upper ends are saturated for longer periods, say the pathologists.
In one of two studies, the SDS-susceptible Hartz 6686 was planted in four rows in a furrow-irrigated soybean field at a branch station in Arkansas. In the three-year study, SDS was most severe at the upper end of the field.
In the second study, four fields with severe areas of SDS were planted to different varieties. In all fields, SDS occurred in large areas, was more frequent and was more severe at the upper ends of fields than at lower ends. The disease occurred at lower ends of fields only when poor drainage allowed water to stand for some time after irrigation.
(J.C. Rupe, R.T. Robbins, C.M. Becton and M.S. Cummings, University of Arkansas)