Ceratocystis fagacearum (fungus)

Most species of oak including red oak, white oak, live oak, Shumard oak, Spanish oak, water oak, black jack oak.

Found Throughout the United States: Midwest, from Texas to Minnesota, Wisconsin and Michigan, Pennsylvania, West Virginia and possibly more.

Infected adjacent oak trees (within 50 feet), root grafts, insects, oak firewood storage or infected oak mulch.

Symptoms vary depending on geographic location and host tree. For example, in the red oak group, affected trees initially show a bronzing or wilting of leaves on an individual branch or in a portion of the tree’s crown. Leaves exhibit a “half-leaf” symptom, where the outer half of the leaf scorches and turns red or brown, while the inner half of the leaf (nearest the petiole) remains green. The fungus will sometimes cause a brown streaking of the sapwood. Within a few weeks, the wilted leaves begin to drop. Wilting spreads throughout the tree canopy during the summer. Most oaks in this group are killed in one season. The white oak group has a greater resistance and may often recover. Live oak appear to be intermediate in resistance.

At the time of wilting, C. fagacearum is present throughout the symptomatic part of the tree and in the roots. Ceratocystis fagacearum may remain alive until the next year in the trunk, and up to four years in the roots, initially growing both toward the inner sapwood and outward to the cambial region and inner bark. Pathogens can spread to adjacent trees by root grafts. Long distance spread can occur from beetle feeding.

DUTCH ELM DISEASE.

Ophistoma ulmi  (Ceratocystis ulmi)   (fungus)

Spread by Vectors that are native and European Elm Bark Beetles.

All native Ulmus (Elm) species: European and Asiatic elms and Zelkova moderately resistant; cultivars of U. carpinofolia resistant are at risk almost anywhere elms grow in north America.

Contributors are elm bark beetles; drought, malnutrition, construction impact; elm firewood or slash, infected elms within 700 feet; climbing spurs.

Watch for yellowing and wilting of terminal leaves in late spring; browning and premature dropping. Twigs tend to turn inward (“shepherd’s crook”). Twig crotches notched by beetle entry. Late spring infection with terminal foliar tufts and sparse leafing; meager chlorotic foliage next spring. Spreads rapidly,  one branch at a time. This kills tree by end of summer; larger trees may survive several years. Mid-summer infection shows on a few branches, becoming severe the next year. Late summer infection stable until next spring, or tree may be free from symptoms next year. Sapwood of infected branches streaked tan or brown. Beetle galleries under bark of larger branches and stems of dying trees. Root graft infection likely where driplines meet, followed by rapid wilting uniformly distributed around crown. Positive identification only by culturing the fungus pathogen in the laboratory.
Overwintering occurs in infected trees, logs, or stumps. Fungus carried by elm bark beetles laying eggs in dying elms; hatch in late fall; larvae tunnel under bark. Larvae develop into pupae the next spring, emerging as adults. Spores in larval galleries sticky, collecting on emerging beetles. Sometimes 3 generations annually. Transmission also through root grafts.

Anoplophora chinensis
The citrus long-horned beetle poses an unprecedented threat to the environment in North America because it attacks healthy trees and has no natural enemies. Not only are greenbelts, urban landscapes and backyard trees at jeopardy, but also orchards, forests, and endangered salmon, and wildlife habitat.

Each female  beetle can make up to 200 eggs after mating, and each egg is separately deposited in tree bark.

After the larvae hatches, it chews into the tree, forming a tunnel that is then used as a place for beetle pupation (the process of growing from larvae to adult). From egg-laying to pupation and adult emergence can take twelve to eighteen months.

Infestations by the beetle can kill many different types of hardwood trees as well as citrus trees, pecan, apple, Australian pine, hibiscus, sycamore, willow, pear, mulberry, pigeon pea, Chinaberry, poplar, litchi, kumquat, Japanese red cedar, oak, and Ficus.

This beetle poses an unprecedented threat to the environment in North America because it attacks healthy trees and has no natural enemies. Not only are greenbelts, urban landscapes and backyard trees at jeopardy, but also orchards, forests, and endangered salmon, and wildlife habitat

Clearwing moths or Sesiidae are a family of the Lepidoptera in most species of which the wings partially have hardly any of the normal lepidopteran scales, leaving them transparent.

The bodies are generally striped with yellow, red or white, sometimes very brightly, and they have simple antennae. The general appearance is sufficiently similar to a wasp or hornet to make it likely that the moths gain a reduction in predation by Batesian mimicry.
This enables them to be active in daylight. They are commonly collected using pheromone lures. Worldwide there are 151 genera, 1370 species, and 50 subspecies. Most of these occur in the tropics, but there are many species in the Holarctic region.

The larvae of the Sesiidae typically bore in wood or burrow in plant roots. Many species are serious pests of fruit-tree or timber cultivation, or crop plants (e.g. Melittia spp. on squash) (Edwards et al., 1999).
These moths should not be confused with the Hemaris genus of the family Sphingidae, which are also known as clearwing moths in the U.S., but normally as bee hawk-moths in Britain. Hemaris moths have generally fatter, furrier bodies than sesiid clearwings, looking similar to bumble bees, and lack the striped colouration.

Cedar Leaf Blight, Cedar Twig Blight, Berckman’s Blight Coryneum berckmanii (fungus), C. thujina

Effects Oriental arborvitae, Italian and Monterey cypress.

Found in the Western Coastal U.S.

With Rain or foggy, cool weather or infested pruning tools.

The Blight on Small branches become reddish-brown, many dropping; larger limbs girdled. Twigs with black pustules of fruiting structures (acervuli). Foliage becoming gray. Dead twigs become entangled at base of tree.

The Cankers on twigs and branches girdled, with cankers first appearing on lateral twigs; slightly sunken, dark, resinous, rough, with black spore pustules. Yellowing and browning of foliage with gummy ooze at cankers.
Infection is first evident in upper part of tree during moist spring. Following initial infection, acervuli produce spores which drop to lower branches or are spread in windblown rain and fog or by birds and insects. Repeated infection leads to death of tree.

Cedar Leaf Blight, Cedar Twig Blight, Berckman’s Blight Coryneum berckmanii (fungus), C. thujina

Effects Oriental arborvitae, Italian and Monterey cypress.

Found in the Western Coastal U.S.

With Rain or foggy, cool weather or infested pruning tools.

The Blight on Small branches become reddish-brown, many dropping; larger limbs girdled. Twigs with black pustules of fruiting structures (acervuli). Foliage becoming gray. Dead twigs become entangled at base of tree.

The Cankers on twigs and branches girdled, with cankers first appearing on lateral twigs; slightly sunken, dark, resinous, rough, with black spore pustules. Yellowing and browning of foliage with gummy ooze at cankers.

Infection is first evident in upper part of tree during moist spring. Following initial infection, acervuli produce spores which drop to lower branches or are spread in windblown rain and fog or by birds and insects. Repeated infection leads to death of tree.

Plectrodera scalator

Cottonwood borers attack trees mostly at the base or below the ground line, sometimes completely girdling the tree.

Eggs are Laid in August and September. The Nymph Stage Looks like the adults but have no wings and are very active. The Adults are 1 – 1 1/2 in., shiny black, with markings of dense white pubescence forming a design; antennae extends three segments beyond apexes of elytra in males, and just beyond them in females. They are black with lines of cream-colored hair forming irregular black patches. Larvae are seldom seen.

Cottonwood borers are found on Cottonwood, poplar, aspen, willows and ranges throughout the eastern Unites States, but highest populations and greatest damage occur in the south.

Extensive mining of bark and cambium occurs, sometimes girdling the stems or roots of young trees. They tunnels through sapwood and into heartwood, filled with frass. Light brown, fibrous frass is sometimes ejected from bark openings at /or slightly above the ground line, accumulating in piles at the base of the tree.

The root collar and roots of infested trees may be riddled by larval tunnels.

The adults appear in mid-summer. After feeding briefly, they descend to the bases of host trees where the female deposits her eggs in small pits gnawed in the bark. Eggs hatch in 16 to 18 days. The larvae bore downward in the inner bark, entering a large root by autumn. Pupation occurs in the gallery from April to June and lasts about 3 weeks. The new adults chew exit holes through the sides of the pupal chambers and emerge through the soil. Some larvae complete development in 1 year, while others require 2 years.

Venturia inequalis, V. asperata (fungus)
Plants affected are Apple, crabapple, pear, firethorn and many other species of Malus throughout North America and Europe.

Cool, wet weather favors heavy leaf infection.

Symptoms first appear in the spring as spots (lesions) on the lower leaf surface, which is the side first exposed to fungal spores as buds open. At first, the lesions are usually small, velvety, olive green in color, and have unclear margins. On some crabapples, infections may be reddish in color. As they age, the infections become darker and more distinct in outline. Lesions may appear more numerous closer to the mid-vein of the leaf. If heavily infected, the leaf becomes distorted and drops early in the summer. Trees of highly susceptible varieties may be severely defoliated by mid-to-late summer.

The fungus, V. inequalis, survives the winter in the previous year’s fallen diseased leaves. In the spring, the fungus in the previous year’s leaves produces millions of airborne spores during rain periods in April, May and June. These are carried by the wind to young leaves, flower parts and fruits. Spores germinate in a film of water, the fungus penetrates into the plant and depending upon weather conditions, symptoms (lesions) will show up in 9 to 17 days. The fungus also produces a different kind of spore in these newly developed lesions. These spores are carried and spread by splashing rain to other leaves and fruits, where new infections occur. The disease may continue to develop and spread throughout the summer.

Cynipid wasp
Scientific Name: Varies
Order: Hymenoptera Several species
Family Cynipidae; gall wasps
Native pests

Description:
Two kinds of galls are produced by this wasp. The most notable are produced by the asexual generation that are spherical, corky, 1/8 to 1 inch in diameter and appear on twigs and branches of live oak in late summer and early fall. When first formed, they are pink to pinkish brown and the yellow-green tissue inside is moist and soft.
A number of cynipid wasps cause unique galls on oak trees: the gouty oak and horned oak gall (woody twig galls), Callirhytis spp.; hedgehog gall, Acraspis erinacei Beutenmuller (leaf galls with orange-colored “hair”); wool sower gall, Callirhytis seminator Harris (stick, spongy galls on twigs with seed-like structures inside); woolly leaf gall, Andricus laniger Ashmead (leaf galls on post oak); and, oak apple, Amphibolips spp. (spherical, spongy-filled galls on red oak). Galls on trees are also caused by other insects such as some species of aphids, flies, phylloxera, psyllids, thrips and mites.

Life Cycle:
Succulent spring galls on oak buds, flowers, and leaves produce fully winged, short-lived males and females. The larvae in the more solid, autumnal galls metamorphose in the fall and depending on species the adults, which are all agamic females, may emerge in late fall (as in Disholcaspis spp.) or stay in the galls over the winter. Often two or more winters pass before the adults finally emerge.

Adults emerge from galls of the “asexual generation” during December. All adults are female and do not mate before laying eggs on swollen leaf buds. Eggs hatch in early spring as leaf buds begin to open. Larvae develop quickly in leaf tissue and stimulate the development of small, beige-colored galls resembling kernels of wheat. Adults of both sexes emerge from these galls or the “sexual generation” after a few weeks. After mating, females lay eggs in post oak twigs and branches. These eggs remain dormant for 3 to 5 months. Then they hatch and stimulate the formation of galls of the asexual generation.

Habitat, Food Source(s):
Damage:
Mouthparts are for chewing. This cynipid wasp species only affects post oak trees. Adults can be reared from galls pruned from trees and placed in plastic bags when larval development is completed.
Pest Status: Although adult wasps are rarely seen, the galls produced on live oak trees around developing stages are noticeable when numerous and can disfigure trees; medically harmless.

Phleosinus sp.  (beetle),

This bark beetle, as others thrives during times of drought and other stresses. The beetles normally attack only weakened juniper trees unless the climate conditions are exceptionally dry.
A healthy  trees have the ability to produce an abundance of sap to push the burrowing beetle out of its bark at the first sign of infestation, but in times of drought, the trees sap production is seriously compromised so even a healthy tree is at the mercy of the bark beetle.

The Larvae are small, white, narrow, short, segmented.
Adults are red-brown to black, shiny, ranging from 1/8-3/8 in. long; rows of teeth at rear of front wings; antennae 5-jointed clubs with oblique depressions.
Their Egg galleries are short, longitudinal with little or no branching, becoming confused with heavy infestations, arising from single entrance hole; larval chambers extend laterally.

All species of Cupressus, Cedrus, Chamaecyparis, Cryptomeria, Cupressus, Juniperus, Libocedrus, Sequoia, Sequoiadendron, Taxodium, and Thuja are hosts.

They are found in the throughout the United States and Canada.
Poor sites, drought, nutritional deficiencies, wounding, and root impaction all contibute.

Twigs yellowing, browning, wilting at tips and hanging; egg and larval galleries immediately under bark; small droplets of pitch below feeding areas on twigs and stems on some species. Host trees usually weak on poor sites or under stress. Trees killed by infestations.

Adults attack all upper parts of weak, dying or dead trees, or broken branches. Prior to constructing egg galleries, adults feed on healthy twigs, hollowing them out until they break over. Egg burrows made by adults working in pairs. Eggs uniformly spaced along sides of burrows. Larvae feed laterally from one egg gallery. Attacks in spring and summer, with 1 1/2 generations per year.