ISHS Acta Horticulturae 177: IV International Symposium on Flower Bulbs
BASAL PLATE ROT OF NARCISSUS BULBS AND ITS CONTROL |
| Authors: | H. Vigodsky-Haas, A. Lavi |
| Abstract:
Premature yellowing of foliage of Narcissus tazetta papyraceus (Paper White) accompanied by root rot and dark sunken basal plates, caused destruction of many commercial crops grown for bulb production. Root and plant development were inversely correlated with the degree of damage to the basal plate of the planted bulbs. Healthy bulbs became infected when grown in naturally infested soils or adjacent to infected bulbs. The nematode Aphelenchoides subtenuis was isolated from affected bulbs (E. Cohn, Dept. of Nematology, ARO; and P.J. Muller, Lab. voor Bloembollenonderzoek, Lisse), but its direct involvement has not been proven yet. The effect of hot-water treatment (HWT) (43.5° and 45° for 4 h and 48°C for 24 h), time of treatment (mid August-mid September) and warm storage (35°C) for one week prior to HWT, on the development of bulbs and on disease control, was studied. All HWT combinations reduced the visible basal rot symptoms in the bulbs harvested in the season following treatment. After the second year's cultivation, over 30% basal-plate rot was found in bulbs treated at 43.5°C at the earlier date and 17% in bulbs treated at the same temperature a month later. Treatment at 45° and 48°C reduced incidence of rot to 6–9%. Warm storage prior to HWT reduced disease control by at least 50%. Bulbs originating as offsets had about half as much disease as those originating from bulbs. | |
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