| SYMPTOMS |
CAUSES |
CONTROLS |
| 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 |
| Many small twigs broken off |
• Twig pruner, twig girdler (insects)
• Wind breakage |
• Rake up and destroy broken and
fallen twigs |
| Large area 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; practice proper pruning techniques |
| • Fungal canker (any of several) |
• Same as for secondary decay |
| General browning of conifer
needles |
• Drought |
• Water deeply |
| • Salt injury |
• Irrigate to a depth of at least
3 feet to flush salts from root zone |
| • Gas leak |
• Check soil around roots for
gray, crumbly appearance and foul smell indicative
of gas leak |
| • Waterlogged soil |
• Improve drainage |
| • Transplant shock |
• Water regularly after transplanting |
| • Girdling roots |
• Be sure main roots are not wrapped
when transplanting; may be necessary to cut rootball
in several places before transplanting |
| Sour-smelling sap oozes from cracks
in bark and/or from old pruning wounds |
• Slime flux, caused by microorganisms
growing in sap |
• Provide proper watering and
fertilization; no chemical or mechanical control |
| Shelf-shaped fungal structures produced
along main trunk and branches; cross-sections reveal
dark, discolored heart wood |
• Heart rot and wood rot (fungal
diseases) |
• Destroy brackets to prevent
spore release; remove badly infected trees; prevent
infection by proper pruning technique |
| Branch swellings, witches' brooms,
progressive decline and death of affected branches |
• Mistletoe |
• Prune out infected branches
1 foot or more from infected sites in the direction
of the trunk |
| Yellow and green mottle or mosaic pattern
on leaves; leaves may be distorted |
• Virus disease |
• Removal of plant may be necessary
if virus is easily spread |
| Foliage becomes sparse; limbs produce
smaller than normal leaves; dry, paper-thin bark cracks
and splits to reveal a black, dusty mass of fungal
spores |
• Sooty canker (fungal disease) |
• Prune out affected branches
at least 4 inches below canker; disinfect pruning
cuts with dilute bleach solution; destroy pruned wood
to prevent further infection |
| Twigs and branches die back; small
black fungal structures embedded in the dead outer
bark |
• Cytospora canker (fungal
disease) |
• Prune out infected branches;
disinfect pruning cuts with dilute bleach solution;
destroy pruned wood to prevent further infection |
| Oozing sap on trunk |
• Natural gummosis |
• Some trees naturally ooze sap |
| • Environmental stress |
• Drought or waterlogging can
cause trees to ooze excessively |
| • Mechanical injury |
• Prevent lawn mower injury |
| Leaves chewed or completely eaten |
• Various caterpillars, sawflies,
leaf beetles, grasshoppers, etc. |
• Use registered insecticide while
insects are small and before damage is extensive |
| Young leaves puckered, curled and distorted;
clusters of small insects on undersides of leaves;
clear sticky substance on leaves |
• Aphids |
• Use registered insecticide or
hard stream of soapy water; thorough coverage of underside
of leaves is necessary |
| Galls (abnormal growths) on leaves,
stems, or branches; common on oaks |
• Various insects or mites |
• There are no chemical controls
for gall insects, but the plants will not be seriously
harmed |
| Proliferation of branches at specific
points on the plant, forming a witches' broom effect |
• Insect injury
• Fungal, viral, or mycoplasma disease
• Mistletoe |
• For all of these, only control
is to prune out affected areas |
| Gray-white powdery growth on leaves;
leaves and fruit may be distorted |
• Powdery mildew (fungal disease) |
• Use registered fungicide; prune
out distorted, mildewed twigs; wettable sulfur is
an effective preventative; do not apply sulfur when
temperatures exceed 90 degrees F |
| Brown, gray, green, or yellow crusty,
leaflike growths on trunk and branches |
• Lichens |
• Lichens are a combination of
algae and fungi; they grow in moist, shady areas and
do not harm the plant |
| Early leaf drop |
• Environmental stress, such as
drought, compacted soil, or transplant shock |
• Provide proper culture |
| • Various insects or disease |
|
| Brown dry areas on margins
of leaves; some species may have irregular brown spots
on leaves |
• Scorch, caused by hot dry weather |
• Water tree deeply |
| • Salt burn |
• Leach soil by irrigating soil
to at least 3 feet |
