Symptoms and Signs
Fig endosepsis is also called internal rot, brown rot, eye-end rot, pink rot, and soft rot. When green, a cross-section of either infected caprifigs or edible figs will show internal streaks of pink or brown, discolored areas on the base of flowers, or sometimes entire flowers are brown. As figs ripen, the brown streaks become rusty colored spots affecting many flowers within the fig. Usually these colored spots are first found in the pulp near the eye of the fig but they can develop on any part of the pulp. No external symptoms are noticeable at this stage of infection.
As figs soften with maturity, a circular area of skin, usually beginning around the eye (ostiole), becomes water soaked in appearance. The water-soaked area eventually extends up the sides to the neck and turns purple in color. Occasionally a clear or amber-colored syrupy liquid exudes from the eye of the fig, especially in fruit of the Calimyrna variety. Even partial infection of the pulp causes off-flavor of the fruit.
In dried figs, fig endosepsis appears as a white powdery layer on the surface of the pulp in the cavity; this is the sporulation of the pathogens at the end of the drying process.
Comments on the Disease
The main causal agent of fig endosepsis is Fusarium moniliforme, but other species of Fusarium can also cause endosepsis. The fungus overwinters in the summer (mamme) crop of the caprifig or as conidia in and on mummified fruit of the summer caprifig crop. In spring, it produces spores that are transferred by the wasp, Blastophaga psenes, when it emerges from the fruit to "pollinate" (caprify) the spring caprifig crop (profichi). The same process occurs on the summer crop of caprifigs. Wasps contaminated with spores of the fungus transmit the disease to edible Calimyrna figs when infected profichi caprifigs are transferred to the Calimyrna orchards for pollination.
Wasps carrying pollen and the fungus enter the Calimyrna figs when they are still green to lay eggs. The wasp dies inside the fruit and the fungus develops on its body. The fungus is unable to invade unripe fig tissue; infection of the pulp occurs later when the fruit begins to ripen. Both caprifigs and Calimyrna figs are affected by endosepsis as are other varieties that are pollinated by the wasp. The disease is also common in volunteer figs. Parthenocarpic (those that do not require pollination) cultivars occasionally develop fig endosepsis.
Collect mamme caprifigs in early March as the wasps start emerging, split the fruit and discard any with internal discoloration. Treat the healthy looking split mammae figs by dipping or spraying with a registered fungicide. Hang treated figs in the profichi (spring) crop of caprifigs.
When selecting profichi caprifigs to transfer to Calimyrna orchards for pollination, discard any that show external discoloration. Also, avoid using too many profichi caprifigs when pollinating the Calimyrna crop. The best way to determine this is to sample 20 or so Calimyrna figs every 2 to 3 days during the pollination period. Split the figs in half and count the number of wasps. An average of one to two wasps per fig is ideal. If there are more than this, reduce the number of profichi figs being used; if there are less, increase it.
|Common name||Amount to use||REI‡||PHI‡|
|(Example trade name)||(hours)||(days)|
|Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least likely to cause resistance are at the top of the table. When choosing a pesticide, consider information relating to the pesticide’s properties and application timing, honey bees, and environmental impact. Always read the label of the product being used.|
|MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M2)|
|‡||Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.|
|#||Acceptable for use on organically grown produce.|
|1||Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode of action Group numbers 1,4,9,11, or 17 before rotating to a fungicide with a different mode of action Group number; for fungicides with other Group numbers, make no more than two consecutive applications before rotating to fungicide with a different mode of action Group number.|