Forest Tree Diseases Flashcards
Annosum Root Disease
Root and Butt Diseases
Caused by fungus, attacks pines and conifers.
White stringy rot at root and butt. Eventually entire root system is destroyed.
Causes slow growth and susceptibility to bark beetle attack, thin crown.
Fungus produces spores the can be moved by wind.
Fungus germinates on freshly cut stumps and roots.
Common in sandy and light soils
Dutch Elm Disease
Vascular Wilt Diseases
Disease causes blockage of water conducting tissue in tree.
Discoloration and wilting of leaves common early.
Infection from European bark beetles, vectors for the disease, fungus deposited in twig crotch in spring
Littleleaf Disease
Decline Diseases
Attacks shortleaf pine and occasionally loblolly.
Fungal disease, shortened, stunted needles. Small cones, few seeds.
Caused by poor soil drainage, common in eroded or shallow, heavier, fine textured soils. Common in stands 40+ years old
Oak Decline
Decline Diseases
Black and Scarlet oak more vulnerable.
Slow growth, thin crown, loss of branches.
Honey colored mushrooms and white fungal growth under bark may be present.
Occurs in VA highlands, common in poor soils and under drought, spring defoliation by insects can make tree more susceptible. Older stands are more susceptible.
Butternut Canker
Canker and Gall diseases
Large canker on main stem, underlying cambium may appear black.
Fungus infests trees through bark wounds like leaf scars. Spores can be moved by rain or insects.
Thrives between 61 and 68 degrees. Germination in lower branches
Fusiform Rust
Canker and Gall diseases
Attacks loblolly and other pines. Orange to brown spores produced in spring.
Football shaped cankers on on loblolly stems.
Common in nurseries.
Requires Water Oaks or Laurel Oaks nearby to complete lifecycle, cannot spread from pine to pine.
More likely in trees <10 years old
Heart Rot
Wood Decay
Starts when fungus invades tree with mechanical damage.
Decay of heart wood.
Dogwood Anthracnose
Foliage Diseases
Spots and blotches on leaves with tan center and purple to red margin, can also have stem cankers.
Infection kills branches and sometimes entire tree.
Shaded areas in higher altitude or moist sites are higher risk
Phytophthora Root Rot
Dampening Off Diseases
Caused by water molds and other soil borne pathogens
Affects Juniper, Yew, and conifers used as Christmas trees.
Kills smaller roots first.
Symptoms: yellowing and wilting of new growth, branch flagging and stunting
Often begins in a nursery, can be spread when saplings are transported
