Bitter Rot of Apples and Pears

Glomerella cingulata

Description:

Small brown spots appear on semi mature fruit and develop in a few days to a large round, dark, sunken lesion that may cover a large portion of the fruit. In humid weather concentric rings of pink spores are produced on the spot. The whole fruit may become dried out and wrinkled or mummified.

Species Affected:

Apple, Pear.
Granny Smith, Gravenstein and Willy Sharp varieties of Apples appear particularly susceptible but all varieties are affected.

Biology:

Spores spread from fruit to fruit by raindrop splash.
Mummified fruit carries the disease from one season to the next.
Spores are produced on fruit or mummies when conditions are wet and temperatures are les than 200C.

Life Cycle:

Origin and History:

Distribution:

Significance:

Management and Control:

Destroy all old fruit and wood in the orchard.
Remove and destroy fruit that has failed to develop on trees.
Remove and destroy diseased fruit from trees regularly.
Reduce humidity around trees by controlling weeds and pruning to reduce the density of the centre of the tree.
Apply fungicides.

Related and Similar Species:

References:

1291

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.HerbiGuide.com.au for more information.