Nematodes

Fusarium Wilt, caused by the soil borne pathogen Fusarium oxysporum f. sp. niveum is becoming more problematic in seedless watermelon production in Southern Maryland. Unfortunately, there are few effective management options for this soil borne disease. New races of Fusarium Wilt are now present in the area that can overcome traditional cultivar resistance. Effective fungicides are limited and do not provide season-long control at labeled rates. In many cases, once a field is infested with Fusarium Wilt, watermelon production is no longer a viable option. One option that has been effective in other areas is grafting of susceptible cultivars onto fusarium resistant rootstocks of interspecific hybrid squash or citron species. Watermelon grafting is more difficult than tomato grafting and is normally done by outside companies who specialize in the technique.

A novel non-native microbe is locally impacting beech tree health and mortality throughout the northeastern United States and southern Canada. The microbe, Litylenchus crenatae mccannii, a subspecies of a nematode found in Japan, is causing beech leaf disease (BLD).

Southern bacterial wilt of tomato, which is caused by the soil-borne bacterium Ralstonia solanacearum Race 1, has been found in several tomato fields just recently. This pathogen affects many solanaceous crops and is found throughout the southern United States.