Production components and yield loss of garlic cultivars planted at different times in a field naturally infested with Sclerotium cepivorum

Four annual experiments with garlic (Allium sativum) were established in fi elds naturally infested with Sclerotium cepivorum, causal agent of garlic w hite rot, to investigate the effect of time of planting on yield. Initial s tands were unaffected by time of planting. Final stands and yields were hig hest when garlic was planted approximately 1 month earlier (28 January-15 F ebruary) when soils were warmer than at the traditional time of planting (1 5 March-15 April). When garlic was planted at the traditional time, final s tands and yields were reduced 56-92% primarily from the attack of S. cepivo rum. A 100% loss in yield occurred in some crops planted in cool soils in l ate March. With an early planting (15 January), final stands were similar t o the plantings of 28 January and 15 February. but yields were reduced by h alf because of a much lower mean weight of the harvested bulbs. In a late p lanting (15 May), the final stand was 75% lower with correspondingly lower yield than that obtained with the early plantings. The largest bulbs (21.6 g) were obtained from the planting on 28 February, however, the yields from this planting were reduced by half from the planting 2 weeks earlier becau se of the 50% reduction in final stand. Early planting of garlic is recomme nded as an important management strategy to avoid white rot in areas with s oils infested with sclerotia of S. cepivorum.