Fungi associated with longleaf pine containers before and after cleaningThis article is part of a larger document. View the larger document here.
Soil was collected from used containers before and after they were cleaned at four nurseries that produce longleaf pine seedlings. The nurseries were located in Florida (FL), Georgia (GA), North Carolina (NC), and Mississippi (MS). The GA and MS nurseries used 5% and 10% bleach (sodium hypochlorite), respectively to clean containers, while the NC nursery used chlorine (5 g/L). The FL nursery did not clean their containers. Fusarium spp. were routinely isolated from the residual container soil; no Pythuim spp. or Pyhtophthora spp. were isolated. The most common Fusarium spp. isolated were F. oxysporum, F. proliferatum, and F. solani. The average number of Fusarium colony forming units (cfu) per container cavity was much higher for FL (2,752 cfu) than for the other nurseries (49 to 309 cfu). No cleaning method was effective in eliminating Fusarium inoculum. Pathogenicity tests with F. proliferatum and F. oxysporum from MS resulted in a significant amount of cankers and some mortality of longleaf pine seedlings. Fusarium proliferatum from FL, GA, and NC caused a mild cankering response. Isolates of F. proliferatum from MS caused damping-off of germinating seedlings. Low levels of F. proliferatum were isolated from unused potting soil at the GA and NC nurseries, but none of these isolates were pathogenic.