| 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 |
