ISHS Acta Horticulturae 480: I International Symposium on Fig
SUSCEPTIBILITY OF MATURING CALIMYRNA FIGS TO DECAY BY AFLATOXIN-PRODUCING FUNGI IN CALIFORNIA |
| Authors: | M.A. Doster, T.J. Michailides |
| Keywords: | Aflatoxins, Aspergillus flavus, Ficus carica |
| Abstract:
Calimyrna figs, while still on the tree, were inoculated with Aspergillus flavus (the aflatoxin-producing species that most commonly decays figs in California) on four dates in August 1994 and on two dates in August 1995. Figs became more susceptible as they matured through the four developmental stages: green with eye (ostiole) closed, green with eye open, yellow, and brown. A. Flavus never grew in green figs with the eyes closed, and only rarely in green figs with the eyes open. The mature brown figs were the most susceptible to decay by A. flavus. In addition, aflatoxin analysis showed that brown figs had more than six times the aflatoxin of yellow figs and more than 30 times that of green figs. In another study, inoculating artificially-wounded figs in the orchard in 1995 and in 1996 resulted in more infections by A. flavus for green figs with the eye open and for yellow figs (compared to the inoculated, nonwounded figs); however, wounding did not result in a significant increase in infections in very immature figs (green with the eye closed) and very mature figs (brown). Similarly, aflatoxin analysis of the wounded figs showed that wounding substantially increased aflatoxin production for green and yellow figs but not for the mature brown figs. These results suggest that damage to mature brown figs does not favor aflatoxin production, which might explain why insect damage to mature figs does not result in increased aflatoxin contamination in figs. | |
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