Correlation between mite population (Aceria cajani) and environmental factors causing sterility mosaic disease of Pigeon pea

Pigeon pea Cajanus cajan (L.) Millspaugh, is one of the major pulse crops of the tropics and subtropics also popularly known as red gram, tuar or arhar is a primary source of protein for millions in India. Sterility mosaic disease (SMD) caused by mite (Aceria cajani) is a major disease limiting the pigeon pea production in the Indian subcontinent. Effect of abiotic factors like temperature, relative humidity and rainfall on mite population was observed during the experiment. Out of theses abiotic factors strong significant correlation was observed with relative humidity. Average temperature of about 20-30°C was found to be congenial for the multiplication of mite. But very high temperature is not suitable for the growth of mite. Heavy rainfall is also not suitable for the growth of mite. Wind velocity is also a very important factor responsible for spreading of disease. The effect of SMD on plant height along with their branches was also observed and can be concluded that severe mosaic affect the plant height, and branches of the pigeon pea plants. The disease severity was high in the early stage of infection causing severe mosaic disease where flower and pod formation was ceased resulting in complete crop failure