CHOANEPHOR A WET-ROT COMPLEX OF AMARANTHUS CRUENTUS (L.): EFFECT OF PLANT DENSITY AND FERTILIZER NITROGEN ON ITS INCIDENCE IN DECAPITATED DIRECT-SOWN PLANTS

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.

IX African Symposium on Horticultural Crops

N.A. Mnzava, T. Ntimbwa, N.M.N. Mollel

https://doi.org/10.17660/ActaHortic.1985.153.32