Symptoms of this fruit rot are similar to late blight, and it is caused by two pathogens that are closely related to the late blight pathogen: Phytophthora parasitica and P. capsici. The latter was found on the affected fruit shown here. These Phytophthoraspecies do not move easily among plantings because their spores are moved by splashing water and in soil, rather than by air as occurs with Phytophthora infestans, the late blight pathogen.
Symptoms are most likely to occur on fruit touching or near soil where the pathogen was surviving between susceptible crops. In contrast with fruit affected by late blight, affected tissue on fruit with buckeye rot are firm and smooth rather than rough.
The white growth on affected fruit is mostly spores of Phytophthora capsici.