| SYMPTOMS |
CAUSES |
CONTROLS |
| Black, sooty growth on leaves, stems, and/or
fruit |
• Sooty mold (fungus that grows on
honeydew substance secreted by aphids and other insects) |
• Identify insect then control as needed |
| Branch dieback; leaves may turn color early in
fall; canker present at or below soil level on trunk |
• Crown rot (fungal disease) |
• Avoid areas with poor drainage; use
registered fungicide; select resistant rootstocks |
| Bark on young branches is rough and pimpled;
tissue beneath bark has brown spots |
• Measles, believed to be a nutrient
imbalance |
• Amend soil as needed |
| Leaves wilt, curl, and cling to twigs; shoot
tip may be curved into "shepherd's crook"; sunken,
black or wine-colored cankers may be present on branches or
trunk |
• Fire blight (bacterial disease) |
• Prune out and destroy affected
branches; remove young suckers as they appear; plant resistant
varieties |
| Pink-white worms bore into blossom end of
apple; clusters of round, brown frass pellets inside fruit |
• Codling moth |
• Use registered insecticide as indicated
by pheromone traps or degree days; clean up fallen fruit; wrap
tree trunk with corrugated cardboard and destroy larvae as
needed |
| White cottony masses found on suckers, trunk,
and branch crotches; trees may show decline |
• Wooly apple aphid |
• There is no control for the
below-ground stage of this root aphid; spray branches with hard
stream of soapy water |
| Leaves skeletonized; common on pear; also
found on cherry, plum, quince, and apple |
• Pear sawfly |
• Apply diatomaceous earth to foliage |
| Tree breaks off at graft union
during strong winds |
• Poorly constructed graft |
• Purchase young transplants from
reliable dealer |
| • Virus infection of graft union |
• Note that some of these viruses are
transmitted by nematodes in the soil |
| Spots form on fruit under the skin; later, in
storage, turn brown |
• Bitter pit, a physiological disease,
caused by reduced uptake of calcium and fluctuating amounts of
water |
• Maintain regular irrigation; rapidly
growing young trees often show this symptom; the problem
decreases with tree age |
