Bitter pit

Small sunken brown pits in the flesh and under the skin of apples, often appearing only weeks into storage.

Disorder Disfiguring Doesn't spread

What you'll see

Slightly sunken dark dimples scattered over the skin, most towards the blossom end
Brown, dry, corky spots in the flesh just beneath the skin when the apple is cut
The affected flesh tastes bitter
Damage often shows up in store rather than on the tree, worsening over weeks
Large fruit from young or heavily pruned trees suffer most

Why it happens

Like blossom end rot, this is a calcium-distribution problem within the fruit rather than a soil shortage. Calcium moves poorly into large, fast-swelling apples, so the cells nearest the skin break down. It is tied to how the tree grows, not to how much calcium is in the ground.

Favored by dry summers with irregular watering, heavy pruning or high-nitrogen feeding that pushes big fruit and leafy growth, and light crops where each apple grows very large. Cooking varieties such as Bramley and Newton Wonder are especially prone.

Treating it

Use affected apples soon rather than storing them, cutting out the corky spots
Do not store fruit from a badly affected tree long-term
Note which trees suffer so you can adjust their care next season

Keeping it away

Water steadily through dry spells, especially on young and container trees
Avoid heavy winter pruning and go easy on nitrogen feeds that force big fruit
Thin the crop less severely on prone varieties so fruits stay a moderate size
Mulch to hold soil moisture even and pick at the right time rather than leaving fruit to size up

Who gets it

Apples are affected, with large-fruited cookers such as Bramley most at risk; pears occasionally show it too.