The Online Gardener's Handbook 2010
Chapter 5: Fruit
Problem Areas on Fruit Plants

Table of Contents

  1. Introduction
  2. Roots
  3. Trunk and Branches
  4. Leaves
  5. Fruit
  6. Learn More

Introduction

Use the following information to identify the cause of your fruit tree problems. Examine the damage on the tree and then refer to the corresponding section. Similar symptoms can result from different problems. When in doubt, consult a qualified specialist for advice.

Roots

Roots rotted, fine fibrous roots, bark strips off easily, discoloured wood underneath.

  • root rot fungi, waterlogged soil
  • tree planted too deeply
  • tree planted in compacted or improper soil
  • nematodes

Roots or lower stem have tumor-like growth

  • crown gall bacteria

Trunk and Branches

Sunken, discoloured, missing or split areas of bark, often with cracked edges; pimple-like structures or gum production on bark.

  • canker-causing fungi
  • bacterial fire blight
  • winter injury (especially on the south and west sides of the tree)
  • improper pruning
  • mechanical wound (lawn mower, etc.)

Bark missing, teeth marks in wood

  • field mouse or rabbit feeding

Small holes in bark with evidence of sawdust; tunnels underneath bark

  • wood-boring insects

Cross-section shows brown staining in wood; may have shelf-like fungi on the bark

  • verticillium wilt fungus
  • wood decay fungus
  • silver leaf fungus

Swollen, dark green to black areas of bark on plum or cherry

  • black knot fungus

Small twigs or entire branches die back; buds are brown inside, dried up or rotted

  • winter injury
  • canker-causing fungi
  • bacterial blights
  • brown rot (peach, plum, cherry)
  • borers

Small bumps on bark that are easily removed with a sharp object

  • scale insects

Leaves

Leaves do not emerge, or wilt, discolour and die
  • abiotic injury: winter injury, severe drought
  • plant girdled by borers, twine, wire or rodent
  • canker-causing fungi
  • verticillium wilt
  • root rot fungi

Leaves turn black or brown on part of plant and remain attached

  • fireblight (apple, pear)
  • brown rot (peach, plum, cherry)

Presence of sticky, shiny honeydew covered with black, sooty mould

  • sucking insects such as aphids
  • scale
  • pear psylla
  • sooty mould

Speckled or discoloured; may dry out and turn bronze or brown

  • spider mites, European red mite
  • leafhoppers

Covered with white powdery mould

  • powdery mildew

Puckered, contorted, stunted appearance

  • peach leaf curl
  • aphids
  • pear psylla

Twisted, cupped, yellow, strap-like appearance

  • herbicide injury

Presence of olive-green to black, felt-like patches

  • apple scab, pear scab

Edges dry and brown

  • drought

Small orange, grey, tan, or brown spots on leaves; sometimes dried tissue falls out, leaving holes

  • frog-eye leaf spot on apple
  • cherry leaf spot on cherry
  • cedar apple rust

Leaves are eaten

  • large holes: caterpillars
  • green parts eaten, only veins remain: skeletonizers (e.g. pear slug, caterpillars)
  • rolled or webbed together: tent caterpillars, leafrollers
  • hollowed-out areas: leafminers

Fruit

No fruit development

  • winter injury, frost injury
  • poor pollination
  • excessive fertilization
  • immature tree

Fruit drops early

  • normal June drop due to excessive fruit set
  • insect infestation inside fruit: curculio, maggots, caterpillars
  • carbaryl insecticide used just after bloom
  • excessive pest injury to leaves (tentiform leafminer)

Blemishes

  • half-moon scar: plum curculio
  • sunken dimples: apple maggot on apple or prune (Italian or Stanley); plant bug on apple, pear, peach; cherry maggot
  • holes in fruit, may have sawdust-like frass: codling moth on apple and pear; oriental fruit moth on peach
  • tiny brown knobs which can be scraped off easily: scale insects
  • rotted, tan to dark brown spots: fungus diseases - black rot on apple, brown rot on peach, plum and cherry
  • dark olive-green to brown felt-like patches, sometimes skin cracks: apple scab, pear scab

Fruit rot on the tree or after harvest

  • soft, watery rot covered with white and black whisker-like mould: Rhizopus rot (peach, plum, cherry)
  • soft, brown rot covered with greyish-brown, velvety mould: Brown rot (peach, plum, cherry)
  • firm, dark brown, target-like rot: Black rot (apple, pear)
  • watery, tan, sunken rot with blue-green and white tufted mould: Penicillium rot (apple, pear)

Small, poorly developed fruit

  • Excessive fruit set
  • Reaction to nearby feeding of aphids
  • Pear psylla or other sucking insects
  • Cedar apple rust or quince rust infections

Learn More


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca