Caught with Your Water Down
Another type of disorder which arises presumably from water stress is one of the fruit pedicel (stem) termed ring-neck. This disorder was first described afflicting the Fuerte variety by J. Elliot Coit in 1928. Horne (1934) provides a good description of this disorder:
It is a blemish, usually on the fruit-stem or pedicel, consisting of irregular areas of superficial dried tissues which become more or less separated from the living tissue. It is particularly likely to affect the thickened segment of the pedicel next to the fruit. Sometimes a complete ring of surface tissue dies,separates from the pedicel,and peels off, leaving a scar. The upper end of the pedicel is slightly fleshy and enlarged, and a small ring-neck spot sometimes occurs on it. Occasionally lesions which have somewhat the appearance of ring-neck develop on the fruit, and where extensive, may give it a grotesque appearance through curling up of the dead surface layer from the edges.
It was originally believed that ring-neck could be caused by a pathogen. Early attempts failed to identify the causal organism. Work in South Africa eliminated pathogen involvement in the development of this disorder. This shows up along the coast where extremes of temperature can occur with Santa Ana conditions. With increased plantings in the Central Valley, it has shown up, as well. Temperature extremes and changing water demand need to be watched in order to avoid this abiotic disorder.
Examples of ring-neck. A. Slight damage to the fruit pedicel. B. Note the peeling of the pedicel tissue.
C. Note that only one fruit (left) is affected with ring-neck.