Influences of Ditylenchus destructor on Stored Garlic and Evaluation of Control Methods

Ditylenchus destructor, a potato rot nematode that infects garlic, was first discovered in Korea. Infectivity, damage during storage, and control methods were studied using garlic cv. Daeseo harvested from farmlands where nematodes naturally occur in the Namhae and Gyeongnam regions. The weight of garlic bulbs (n=5, randomly selected) ranged from 30.7 g to 41.2 g, with an average of 9.6 cloves per bulb and each garlic clove averaging 3.8 g. An average of 1,204 nematodes were detected per garlic clove, with a maximum of 14,400 nematodes. There was no significant correlation between garlic clove weight and nematode density (r=0.0153), but the higher the density of D. destructor, the faster the weight decreased with storage period. After storage for 12 weeks, garlic without nematode infection (n=88) lost an average of 8% of its weight, while garlic infested with D. destructor (n=78) lost 22-31% of its weight. In field experiments, plots planted with tissue-cultured garlic (nematode-free) had a 1.49-fold increase in yield compared to the control, while no significant yield increase was observed in plots planted with NaOCl or hot water treated garlic. Therefore, the use of tissue-cultured garlic is recommended as an effective method to reduce garlic yield loss caused by potato rot nematodes.