07-08-2013, 01:14 PM
Influence of abiotic environmental factors on the progress of French bean rust
ABSTRACT
Rust (Uromyces appendiculatus) is an important disease of french bean particularly of pencil types in mid hills of Himachal Pradesh. Present investigations were undertaken with an objective to study the role of abiotic environmental factors in disease development. The data on weather parameters and disease development revealed that the disease appeared in the third week of August. Since the environmental factors viz., temperature, average relative humidity and cumulative rainfall influenced the disease development, simple, partial and multiple correlations were therefore worked out to establish the contribution of these factors individually or jointly in the progress of the disease among the host population. Above study revealed that moderate temperature (20ºC) and high humidity (>85%) were found to be most congenial factors for disease development, whereas high rainfall was deleterious to the disease. Multiple correlation coefficient between bean rust severity and group of independent variables was found to be 0.7082 which indicated that 70.82 per cent bean rust severity was caused by mean air temperature, average relative humidity and cumulative rainfall collectively whereas rest of the variation was due to unexplained (error variation) factors and/or the factors not included in the investigations.