Development of leaf rust (Peridiopsora mori) and dispersal of urediniospores in mulberry (Morusspp.)

Abstract

Studies were conducted on the effect of pruning time, host age, urediniospore release and weather parameters on the incidence and intensity of mulberry leaf rust (Peridiopsora mori). Rust severity significantly increased with increasing shoot age, irrespective of pruning time. Maximum disease severity was observed in plants pruned during the third week of October, and minimum severity in plants pruned during last week of November. Apparent infection rate was higher in younger shoots. Infection rate was higher in plants pruned during the last week of November. Urediniospore release was influenced by prevailing climatic conditions. A higher rate of spore release was noticed during sunny days. Maximum spore release was found between 12.00 h and 14.00 h. Spore release was positively correlated with temperature and negatively correlated with relative humidity. Rust severity (34.97%) was higher in January and least (1.03%) during May. Rust severity was negatively correlated with both temperature and rainfall. An exponential model was developed for the prediction of rust severity which was accurate up to 96.60%.

Factors Influencing Development and Severity of Grey Leaf Spot of Mulberry (Morus spp.)

“…As leaves age, longer period of leaf wetness is required for infection (Turechek and Stevenson, 1998). Similar results on the higher disease severity in older plants were reported in case of rust infection in mulberry (Pratheesh Kumar et al, 2000). The susceptible stage in a plant may appear after the pathogen inoculum has been weakened or exhausted.…”

“…The higher apparent infection rate per unit area per day in young plants rather than in the mature old ones observed may be due to the establishment and colonization of the pathogen in the early growing stage and thereafter the growth of pathogen in a steady rate. The fungi utilize food material available in the leaves for the establishment and colonization which causes a deficit in food materials for subsequent growth of the pathogen reducing in the apparent rate of infection in more mature and older plants (Pratheesh Kumar et al, 2000). Environment influence the epidemics of diseases through its various structural elements.…”

Epidemiology and prediction of brown leaf rust of mulberry caused byPeridiopsora mori

“…Pratheesh Kumar et al (2000) reported that leaf rust disease severity shows significant correlation with temperature and rainfall in plains of West Bengal. Maji et al (2010) reported that leaf rust has significant negative correlation with maximum and minimum RH, number of rainy days and positive correlation with bright sunshine hours.…”

“…Weather based disease prediction models have been developed for management of wheat rust (Eversmeyer et al 1973;Nagarajan and Singh 1975;. In mulberry, Pratheesh Kumar et al (2000) developed forecasting equation of leaf rust of the Gangetic plains of West Bengal. Maji et al (2010) developed forecasting models of leaf rust for Orissa region.…”