infection may reduce growth potential by decreasing leaf photosynthetic area. Premature defoliation of highly susceptible trees is common. Spores

of host trees. Hibernating adults emerge and are attracted to new susceptible host trees by their

more than 20 percent. Trees defoliated early in the growing season are more susceptible to other

maple and sugar maple are readily attacked, and other maples are probably susceptible. Mountain-ash has been

and kill small trees; newly transplanted trees and those weakened or stressed are most susceptible. 5 8 9 10

and other southern hardwoods such as sweetgum, white oak, and nuttall oak are very susceptible to Scytinostroma

and tree death. Secondary organisms enter trees through cankers, causing stain and decay. Highly susceptible clones cannot be coppiced

such symptoms. Carefully monitor poplars from the Tacamahaca section because they may be especially susceptible. Willow is also susceptible

and kill small trees; newly transplanted trees and those weakened or stressed are most susceptible. 5 8 9 10

by other diseases (e.g. soybean cyst nematodes or Fusarium root rot) or agronomic practices are more susceptible to Septoria

Biology 5 Control 6 Gallery Importance Sycamore seedlings and other southern hardwood species are susceptible to Cylindrocladium

and kill small trees; newly transplanted trees and those weakened or stressed are most susceptible. 5 8 9 10

and kill small trees; newly transplanted trees and those weakened or stressed are most susceptible. 5 8 9 10

and kill small trees; newly transplanted trees and those weakened or stressed are most susceptible. 5 8 9 10

and kill small trees; newly transplanted trees and those weakened or stressed are most susceptible. 5 8 9 10

in the bottomlands of Arkansas, Louisiana, and Mississippi seems particularly susceptible, and young

Solomon and others 1987). Upland oaks, especially black and scarlet oaks, are particularly susceptible (Buchanan 1960). Elm, poplar

producing trees. Girdled branches can create cleanup problems on residential properties. Young transplanted trees are particularly susceptible to borers

are recorded hosts (Beutenmuller 1901, Engelhardt 1946). Many other species of poplars are probably susceptible. Willows seem preferred in

persimmons grafted onto the native persimmon rootstocks are sometimes attacked. Improved varieties are probably susceptible. Range Throughout the

a pest infestation. Often, but not always, plants that are nutrient or water stressed are more susceptible to pest

deep ploughing or spading to bury diseased plant debris; by rotation of susceptible with nonsusceptible crops to

are often hollowed or severed. Opengrown trees and those weakened by disease are most susceptible. Young, vigorous trees are

trees throughout North America. Severe defoliation in consecutive years can weaken trees, making them susceptible to attacks

bugs. Apply any time the bugs are present. Plant resistant clones. Do not plant susceptible clones next to

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

foliar regrowth (fig. 26). Acremonium wilt is favored by hot weather (> 30º C). Wilted sycamores are susceptible to infection

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

The spores are spread by the wind to branch stubs on susceptible trees where infection occurs

fungus grows, it can penetrate the root system or collar of nearby susceptible trees. The wood

before decay becomes extensive. Harvest stands damaged by fire or weather early because such stands are susceptible to infection

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

One generation is produced annually. All species of elms appear to be susceptible to European

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

of high value trees has been effective in keeping bark beetles from attacking susceptible trees. Space trees further

trees throughout North America. Severe defoliation in consecutive years can weaken trees, making them susceptible to attacks

reported on most coniferous species, and all species of southern pines are susceptible to attack

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

of evergreen ornamentals in the South. Arbovitae and juniper are particularly susceptible. If infestations are heavy

to adjacent trees. Trees weakened by mechanical wounding or stressed by other pests are more susceptible to attack

severely diseased than those growing at wider spacings. Only young shoots and leaves are susceptible. Later in the

Red and live oaks (in Texas) are more severely affected than white oaks. Susceptible trees may be killed

ground line. Upper shoots of small trees nipped off. Biology - Young trees are especially susceptible to damage

are often hollowed or severed. Opengrown trees and those weakened by disease are most susceptible. Young, vigorous trees are

in susceptibility to attack. Clones of Populus x jackii are especially susceptible. Control - Plant aphid-resistant

reported on most coniferous species, and all species of southern pines are susceptible to attack

oaks throughout the East. Trees weakened by drought, defoliation, or other factors are most susceptible. Larvae destroy the

hickory, and butternut. Defoliation may weaken the tree and make it susceptible to damage

Journal of Forest Pathology. 14: 202-218. Leaves infected by M. populi. Leaves from susceptible clone (left) and

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

in crevices of rough bark on branches and trunks of susceptible trees. They prefer trees

throughout the East. Trees weakened by drought, insect defoliation, or other factors are most susceptible. Larvae mine the

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

sawfly for two or more years can weaken trees and make them more susceptible to other

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

and destroy. 5. Maintain high tree vigor with cultural practices. 6. Open-grown trees most susceptible; maintain good stocking. 7

under the bark. Stems that are weakened or dying from other causes are particularly susceptible. Look For - Dead

the gallery. A generation requires 2 years. Control Open-grown trees are most susceptible, thus maintain a

Goeden and Norris 1964, Hopkins 1912, McDaniel 1936). Pecan and butternut are less susceptible. Range Quebec south throughout

Crombie 1911). Except for evergreens, most woody plants of suitable size appear susceptible (Howard and Chittenden

of all sizes. Trees that are wounded, diseased, or in poor vigor are most susceptible to attack

a variety of pests (pathogenic fungi, insects, nematodes, and weeds). Rotating susceptible and nonsusceptible

25). Trees cut back so severely that the trunk becomes saturated with sap are susceptible to infestations

sassafras trees from 6.3 to 51.0 mm in diameter are susceptible to attack

on the bole area just below the lower branches. Small trees are particularly susceptible to attack

in the summer and fall to observe adult females ovipositing on susceptible tree trunks. Dead female

cage studies show that typical larvae wander considerably during development and repeatedly burrow into susceptible shoots for 1

in this guide. However, growers must be aware that many commercially available clones are extremely susceptible to certain

Boving 1929). Sycamore, mahogany, ceanothus, and fruit and nut trees seem particularly susceptible (Davis and others1968

disease of soybean in the Midwest. Usage of less susceptible cultivars helped curbing the

25). Trees cut back so severely that the trunk becomes saturated with sap are susceptible to infestations

is typically an early- to mid-season disease on soybean. Management Approaches Avoid using susceptible varieties. Seeds produced in

required. Injury and Damage Stressed, dying, and recently dead trees are most susceptible to attack

and others 1931, USDA FS 1985). Because young transplanted trees are stressed and particularly susceptible, additional measures may be

28. Asheville, NC: USDA Forest Service, Southern Research Station. 44 p. Because healthy trees are less susceptible to attack

All parts of a tree over 3 cm in diameter are susceptible to attack

entire stands, reducing radial and terminal growth and weakening trees, making them susceptible to other

by the poplar borer (Saperda calcarata Say) and hypoxylon canker are particularly susceptible (USDA FS 1985). Evidence

of weeks in the summer and lay eggs into into susceptible seedheads as they become

R.P.; Sterling, T.M.; Lownds, N.K. 1998. Effect of picloram on resistant and susceptible yellow starthistle (Centaurea solstitialis

many young larvae (Underhill 1935), and both larvae and pupae are highly susceptible to desiccation

trees and those weakened by disease, drought, machanical damage, or soil conditions are most susceptible to attack

many borers may be in a tree. Trees with old damage are more susceptible and repeated

balsam poplar and the hybrid poplars are also attacked. Many other poplars probably susceptible. Observed occasionally in

trees and those weakened by disease, drought, machanical damage, or soil conditions are most susceptible to attack

Moznette and others 1931). Since young transplanted trees are under stress and particularly susceptible, additional measures may be

5 months; thus, three generations seem possible (Blackman 1922). Injury and damage Bark on susceptible trees and fresh

resprout each spring from their large rootstocks (Figure 5). Any sunny or partially shaded wetland is susceptible to purple

the tree. Trees stressed or weakened from drought, fire, storm, disease, or other cause are most susceptible to attack

and bitternut hickories (Beal and others 1952, Solomon 1974). Other hickories are probably susceptible, and evidence

ash ( Fraxinus spp.) species; however, green ash , white ash , and black ash are more susceptible than Asian varieties. Pathways

and crown dieback. Open-grown trees, such as those in seed orchards, are particularly susceptible. This borer was not

resistant to damping-off. Increased nitrogen most likely promotes formation of succulent, susceptible tissues. Soil fertility is

with a small body size and long body hairs, makes this stage very susceptible to airborne

the mite and of being infected by RRD. Many cultivars are very susceptible to RRD

in color from off-white to orange. Both conifers and hardwoods are susceptible to a

of Illinois. In field trials it significantly reduces aphid populations compared to susceptible controls. Rag1 soybean lines

flowers. These key pests often have special times (windows of opportunity) that they are susceptible to controls