Nutritional status of soils and the incidence of bunchy top disease of bananas (Musa species) part V - effect of combined application of calcium and magnesium to soil on the ratio of calcium oxide/ magnesium oxide in the plant and its relation to bunchy top infection

Abstract

The experiment to study the effect of combination of calcium and magnesium application to soil on the calcium oxide/magnesium oxide ratio in the plant and on the bunchy topdisease of banaa, was laid out under semi-field conditions. Calcium oxide and magnesium oxide were applied in the ratios 3:1 and 6:1 at two levels of magnesium 0.05 and 0.10 per cent by weight of soil. Uniform levels of nitrogen, phosphorus and potassium in all treatments were given by application of equalquantities of fertilizers. No organic manure was added, to avoid too many uncertain factors which might have influenced the behaviour of calcium and magnesium in the soil and absorption by the plants. The concentration of the insect inoculum was maintained at a uniform level , by releasing infective sphids at the rate of 25 each . Inoculation was done four months after planting. To avoid natural infection before inoculation, periodical sprays of parathion 0.01 per cent had been given as a regular practice.