| SYMPTOMS |
CAUSES |
CONTROLS |
| Premature fruit drop |
• Natural thinning |
• Trees may produce more fruit than they
need and thin themselves naturally |
| • Spring frost |
• Frost often kills developing fruits or
buds |
| • Poor pollination |
• Tree may require other trees nearby to
pollinate it; be careful not to kill bees with insecticides |
| • Environmental stress |
• Drought, cold, or heat can cause fruit
drop |
| Poor fruit development (small
number of fruit on tree) |
• Poor pollination |
• Tree may require other trees nearby to
pollinate it; be careful not to kill bees with insecticides |
| • Biennial bearing |
Apples and pears naturally bear a heavy crop
one year and few fruits the following year |
| • Improper pruning |
• Do not prune off fruit bearing wood
during the dormant season; consult pruning manual for proper
instructions on pruning |
| • Frost injury |
|
| Fruits too small |
• Failure to prune |
• Peaches, nectarines, plums, and apples
tend to produce many small fruits if not pruned; consult pruning
manual for proper pruning |
| • Failure to thin fruit |
• Thinning fruit is necessary on some
fruit trees |
| • Poor soil fertility |
• Amend soil as needed |
| Rapid wilt and death of plant with dead or
dying foliage remaining attached; roots of larger trees are
decayed and brown |
• Texas root rot (fungal disease) |
• No chemical control is available; see
Extension bulletin for care of affected plants |
| Oozing sap on branches or trunk |
• Natural gummosis |
• Cherries, plums, apricots, and peaches
naturally ooze sap |
| • Environmental stress |
• Drought or waterlogging can use fruit
trees to ooze excessively |
| • Disease or insect damage |
• See section on specific problems |
| • Mechanical injury |
|
| Large areas of split bark; no
decay evident |
• Frost cracks |
• Frost can split tree trunks if sap in
trunk expands; use tree wrap or tree paint to protect bark from
sun and extremes in temperature |
| • Sunscald |
• Thin-barked trees, e.g. young ones,
split when exposed to intense sunlight; use tree wrap or tree
paint, especially during winter months |
| • Mechanical injury, e.g. lawn mower |
• Dig up grass around trunk and replace
with mulch to avoid mowing too closely to base of tree |
| • Lightning injury |
|
| Large areas of split bark; decay
evident in wood |
• Secondary decay of wounds |
• No adequate controls; remove loose
bark; follow proper pruning techniques |
| • Fungal or bacterial canker (any of
several) |
• Same as for secondary decay |
| Brown dead areas on leaf margins |
• Leaf scorch |
• Water tree deeply during dry periods;
scorch is usually caused by hot, dry weather, but root rots or
other root damage can also be involved |
| Interveinal yellowing of leaves;
no wilting |
• Iron deficiency |
• Apply chelated iron solution to foliage
or soil, depending on formulation and tree species |
| • Waterlogged soil |
• Improve drainage |
| Young leaves curled and distorted; clusters of
insects on undersides of leaves |
• Aphids |
• Use registered insecticide or hard
stream of soapy water; thorough coverage of underside of leaves
is necessary |
| Silk tents in branch crotches in spring |
• Tent caterpillar |
• Physically remove tents or use
registered insecticide when caterpillars are small |
| Leaves with tiny white spots, often dirty with
webbing |
• Spider mites |
• Use registered miticide or spray
foliage regularly with water |
| Bark encrusted with tiny, slightly raised
bumps; apples may have red spots with white centers |
• San Jose scale |
• Use a dormant oil spray |
| Internodes shortened, giving foliage a bunched
appearance; yellowish mottling of leaves; shoot dieback |
• Zinc deficiency |
• Apply foliar application of zinc in
fall before leaf drop; summer zinc applications on fruit trees
may cause defoliation |
