Relation between the age of rice plant and its susceptibility to Helminthosporium and blast diseases

Abstract

The susceptibility of rice plants of different ages to Helminthosporium disease was studied by conducting artificial infection tests on three different dates during the season. Three varieties, 2 susceptible and a resistant were included in the study. It was found that the susceptibility increased with age of plants and the relative susceptibility of varieties, as compared between plants of the same age remained the same at any time during the season. Inoculations carried out in September produced the maximum infection. Susceptibility to Blast disease at different ages was studied in 2 field experiments. It was found that younger plants were most susceptible and the resistance increased as the plants grew older. Only the post-planting age of the plants had an effect on their susceptibility.