Factors affecting the incidence of black seed rot in slash pine

Black seed rot of slash pine (Pinuselliottii Engelm. van elliottii) caused by Lasiodiplodiatheobromae (Pat.) Griff. & Maubl. was found to be a postharvest disease favored by premature cone harvests in conjunction with certain cone collection practices. The incidence of fungus-damaged seeds was greatest in cones collected on the earliest collection date and left in contact with the ground before storage. The incidence of disease decreased with later collection dates. Fungus-damaged seeds were not present in cones dried immediately after collection, regardless of the collection date. Fungi were rarely established in seeds at the time that cones were removed from trees; they apparently colonized seeds and caused disease during cone harvest and storage. Based on cone specific gravity and results of seed germination tests, cones and seeds were not mature on the earliest collection date. Lasiodiplodiatheobromae was associated with a majority of seeds that were fungus-damaged. Sphaeropsissapinea (Fr.) Dyko & Sutton and a Fusicoccum sp. also were recovered from seeds; however, their relative importance in slash pine seed disease was minor.