Bio (Bacterial) control of pre- and postharvest diseases of root and tuber crops

Abstract

The term root and tuber crops is a very general catch-all for a wide cross-section of subterranean storage organs of which there are approximately 38 root, 23 tuber, 14 rhizome, 11 corm, and 10 bulb crops. The most important among them are potato, sugar beet, carrot, onion, and garlic (temperate root and tuber crops) and cassava, sweet potato, yams, and aroids (tropical root and tuber crops). Pre and postharvest losses of these crops are very high and, depending on the species cultivated and the storage environment, may be of the order of 30-60%. Bacterial control has been emerging as a promising alternative to chemical fungicide to control many pre- and postharvest diseases of these crops. The underlying mechanisms include antibiosis, competition for nutrients and space, and systemic resistance. The various strategies for use of antagonists and field uses (i.e., seed treatment, soil application, foliar spray, antagonistic mixture) have been discussed. In addition, certain mechanisms to improve performance of antagonists, such as addition of nutrients, use of antagonist mixture, and formulation of antagonist have been emphasized in this chapter.