ISHS Acta Horticulturae 153: IX African Symposium on Horticultural Crops
CHOANEPHOR A WET-ROT COMPLEX OF AMARANTHUS CRUENTUS (L.): EFFECT OF PLANT DENSITY AND FERTILIZER NITROGEN ON ITS INCIDENCE IN DECAPITATED DIRECT-SOWN PLANTS |
| Authors: | N.A. Mnzava, T. Ntimbwa, N.M.N. Mollel |
| Abstract:
A disease of amaranth, the wet-rot caused by Choanephora cucurbitarum on young leaves and stalks, was studied in two field experiments in relation to plant density and applied N on direct seeded Amaranthus cruentus harvested by repeated cutting. Densities of 44, 65, 100 and 196 m-2 were tested. Wet-rot incidence, assessed once a week after the first cutting, increased significantly with plant population causing plant losses of 6.9, 18.5, 14.2 and 20.0% in that order. In a separate experiment, using the optimum density of 144 plants m-2, applications of N as ammonium sulphate at 0, 5.04, 21.84 and 42.84 g m-2 increased disease incidence and caused losses of up to 60% with the highest N dose, compared to 23% for the control. The results suggested that disease incidence was related to inter-plant competition, and lush vegetative growth caused by increased N. Nitrogen was more important than plant density, as a factor in disease incidence. | |
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