WSU Extension

Hortsense

Apple
 
Disease
Anthracnose and Bull's-eye rot 
Bitter pit 
Burrknot 
Crown and collar rot 
Crown gall 
Cytospora canker 
Fire blight 
Fruit russeting 
Nectria canker (European canker) 
Nectria twig blight (Coral spot) 
Perennial canker (Bull's-eye rot) 
Phytophthora fruit rot 
Powdery mildew 
Scab 
Virus diseases 
Insect
Aphids 
Apple ermine moth 
Apple maggot 
Apple-and-thorn skeletonizer 
Brown marmorated stink bug 
Codling moth 
Cutworms and armyworms 
Earwigs 
Fruittree leafroller 
Leafhoppers 
Leafrollers 
Lecanium scale 
San Jose scale 
Spider mites 
Tent caterpillars 
Tentiform leafminer 



print version| pdf version| email url    
Caption: Apple bitter pit
Photo by: C.R. Foss
  
Apple : Bitter pit
(revision date: 5/20/2014)


Biology
Bitter pit of apples is a physiological problem which results from calcium deficiency in the fruit. Depressed spots appear on the fruit surface and the tissue beneath the spot becomes brown. The spots may be up to 1/4" in diameter and are most often seen near the blossom end of the apple. Later, the spots will become sunken and somewhat dry and corky in texture. Several cultural practices can increase the occurrence of bitter pit. Heavy pruning and large nitrogen applications result in vigorous shoot growth and increase bitter pit. Irregular watering, drought stress, and hot summer weather can also contribute to the problem, as will injuries to the trunk or roots which interfere with water and nutrient uptake. Certain apple varieties are more prone to this cultural problem.
Management Options

Non-Chemical Management
  • Plant resistant varieties such as 'Delicious' and 'Winesap' when practical (these varieties may be susceptible to other problems). The variety 'Buckley Giant' is extremely susceptible to bitter pit.
  • Avoid heavy pruning and other practices which result in vigorous growth.
  • Fertilize properly. Avoid excessive nitrogen applications.
  • Maintain a constant soil moisture supply.
  • Avoid injury to trunks and roots.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

+ Show larger images

 
Caption: Apple bitter pit
Photo by: C.R. Foss