ALLEVIATION OF THE DAMAGE OF FABA BEAN CHOCOLATE SPOT AND RUST DISEASES BY SOME NUTRITIONAL ELEMENTS

Laboratory and filed experiments were conducted in 2005/2006 and 2006/2007 winter seasons to study the effect of some nutritional elements (ferrous, zinc, manganese and calcium) at 2, 4, 6 and 8 g/L on chocolate spot and rust diseases of faba bean. The laboratory results, declared that zinc and manganese at 6 g/L completely inhibited the linear growth and sporulation as well as mycelial dry weight of Botrytis fabae. However, ferrous at 2 g/L or calcium at 8 g/l has no effect on neither linear growth nor mycelial dry weight.
The results of field experiment show that calcium at 6 g/L led to maximum reduction of chocolate spot and rust diseases severity followed by manganese at 4 g/L then zinc at 4 g/L. The highest value of plant height occurred under zinc at 4 g/L followed by 6 g/L calcium which increased significantly number of branches/plant. There was positive relationship between number of pods/plant and calcium levels treatment from 2-6 g/L. Calcium at 6 g/L and 4 g/L gave the highest values of 100-seed weight followed by manganese 4 g/L.
Total phenol contents reached their maximum when faba bean sprayed with 2 or 4 g/L calcium followed by ferrous (6 g/L) then manganese (6 g/L). Also, the highest concentrates of chlorophyll a, b and caroteinoids occurred under the application of calcium at 2 g/L.
It is clear from this study that there is no significant differences between the efficacy of calcium at 4 or 6 g/L and Diathine M-45 also between manganese (4 g/L) or calcium (6 g/L) and Plantvax 20% EC effects in reducing faba bean chocolate spot and rust diseases, respectively.
In general, some of nutritional elements are promising trend in controlling of chocolate spot and rust diseases of faba bean, where it decreased the infection, environmental friendly and coast effective compared with the ordinary fungicides.