Usually affects Persian and Bearss limes but can be on other limes and lemons. Depressed areas are firm or leathery and dry. It starts out looking like a water soaked, whitish-to-drab sunken patch at the base of the stylar tip (end) and can cover 1/4 to 1/2 of the fruit. Inside tissues at stylar end break down and become pinkish or brownish.
You can pick before mature to cut losses. Extremely high temperatures can bring it on.