Effect of fruit removal on carbohydrate concentrations of cantaloupe (Cucumis melo L.) roots in naturally infested soil with Monosporascus cannonballus

The effect of fruit removal from cantaloupe was studied under field conditions in a soil naturally infested with Monosporascus cannonballus. Fruit removal resulted in greater sugar accumulation in the cantaloupe roots compared to the roots from plants on which the fruits were allowed to develop normally. Individual, total, and combined root carbohydrate levels were greater in plants without fruit than in plants with fruit. Five major sugars (stachyose, raffinose, sucrose, glucose, and fructose) were found in the cantaloupe roots. Stachyose concentrations were higher than all the other sugars in the cantaloupe roots. Disease severity on the cantaloupe roots with fruit removed was less severe than on roots of plants with fruit, and dry weights were higher in the fruit removal treatment than those of the fruit non-removal treatment. Fruit removal results in increased root growth and carbohydrate accumulation in the cantaloupe roots. Root sugar concentrations affected infection efficiency and disease progress of Monosporascus root rot and vine decline. Therefore, the retarded development of Monosporascus root rot and vine decline is associated with a greater carbohydrate accumulation in the cantaloupe root.