Diplodia and Botryodiplodia root rot of pines.
D. pinea was confirmed as the primary pathogen of a root rot in 10-yr-old Pinus elliottii stands in the Leizhou Peninsula, Guangdong Province. B. theobromae was also identified from P. elliottii, P. taeda and P. caribaea. P. elliottii was more susceptible to inoculation with D. pinea than P. taeda or P. caribaea, while P. massoniana was resistant. Mycelia of D. pinea could survive for >150 d in infected roots of P. elliottii under natural conditions, and for >120 d in natural soil at different water contents. Conidia also survived for >120 d in soil with 5-50% water, indicating that D. pinea is probably a soilborne fungus. Low water content was conducive to root infection by D. pinea; at levels >50% it was more difficult for the pathogen to attack. Low soil water content for 20 d could increase seedling susceptibility.