Effects of three fungicides used to control powdery mildew in mango on pollen germination and pollen-tube growth.
Dag A., Eisenstein D., Gazit S.
Author Affiliation: The Kennedy-Leigh Centre for Horticultural Research, Faculty of Agricultural, Food and Environmental Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel.
Proceedings of the Interamerican Society for Tropical Horticulture 43 : 123-126
Abstract : Three fungicides (dinocap, hexaconazole and fenbuconazole) used for the control of powdery mildew, caused by Oidium mangiferae, in mango (Mangifera indica) were tested for their effect on pollen germination on the stigma and pollen tube penetration into the ovary. Flowers were detached at anthesis and their pedicels were inserted into 2% agar. Within 2 h, they were sprayed with dinocap (0.04% Karaten) or the triazole fenbuconazole (0.04% Indar). Dehiscence occurred 2 to 3 h after spraying, and flowers were then hand-pollinated and kept for 24 h at 30°C. Dinocap reduced pollen germination and pollen tube penetration into the ovary. The effect of dinocap was compared to that of the triazole hexaconazole (0.02% Invil) in a commercial scale trial. No noticeable difference between the two fungicides was found in terms of the percentage of flowers with germinating pollen on the stigma. However, a significant decrease in pollen tube penetration into the ovary occurred in flowers sprayed with hexaconazole. These findings indicate that fungicides used for powdery mildew control in mango should be tested for their effect on the fertilization process, preferably by testing the ability of the pollen tube to reach the ovule.