SOME RELATIONSHIP BETWEEN PLANT NUTRITION, FUNGAL POPULATIONS, AND INCIDENCE OF FUSARIUM WILT OF MUSKMELON

Abstract

The rate of muskmelon wilt was shown to be a function of the amount of nitrogen available to and absorbed by the plant. Since NH₄NO₃ nitrogen did not increase the size of the soil population of either F. oxysporum or the wilt component, F. oxysporum f. melonis, it is concluded that its effect is through an increased host susceptibility. The effectiveness of nitrogen on wilt is expressed at all population levels of the wilt fungus, highest rates of wilt being found in soils with highest populations. Calcium and potassium retarded wilt in less highly fertilized soils and caused a reduction in population of the wilt fungus. Interactions of nitrogen, potassium, phosphorus, calcium, and magnesium are discussed.