Proteoteras willingana

Proteoteras aesculana

Synanthedon acerni

Prodiplosis morrisi

Neopulvinaria innumerabilis

Parthenolecanium corni

Eriosoma lanigerum (on-malus)

Monarthropalpus flavus

Zeuxidiplosis giardi

Chrysomyxa arctostaphyli

Proteoteras willingana 

Hosts: Boxelder, maple. Boxelder is the major, possibly only, host (Peterson 1958). However, other maples have been mentioned as hosts (MacAloney and Ewan 1964)

Two kinds of injury are important. The first, observed mostly in Canada, is the destruction of dormant buds from mid-August to early fall and from late April to early May (Anonymous 1971). The second, larval burrowing in succulent growing shoots, causes stem breakage stunting, and mortality. Fine, dark brown or black frass often protrudes from entrances a few centimeters below the apex or from the shoot tip. Feeding activity stimulates infested twigs to enlarge abnormally, forming spindle-shaped, gall-like swellings. Larval entrance holes can be found usually toward the lower ends of the galls. Burrows become quite extensive, resulting in tunnels 25 mm or longer. Splitting the swollen shoots reveals tunneling larvae. It attacks trees of any age, from first-year seedlings in nurseries to mature trees in urban and rural plantings. This borer occurs in almost all boxelder plantations in Manitoba, Saskatchewan, and Alberta. Up to 50% of the new growth may become infested with up to 30 twigs infested on a stem. New shoots are often killed or break, and terminal growth is prevented. Heavy outbreaks stunt established trees by killing much of the current tip growth on twigs and branches. Secondary branching results, and when this growth is also destroyed, the affected trees may fork repeatedly, becoming bushy and undesirable as shade trees (MacAloney and Ewan 1964).

Range: Throughout the eastern United States west through the Great Plains. Also found in southern Canada. Most troublesome in the Great Plains of the United States and the Prairie Provinces of Canada, where boxelder is grown extensively for shade and farm shelterbelts (Peterson 1958)

Proteoteras aesculana

Hosts: Maple, boxelder. Silver maple, boxelder, sugar maple, and bigleaf maple have been listed specifically. Other maple species are probably hosts (Craighead 1950, Powell 1962).

Larvae hollow out dormant buds and seeds in fall and continue to feed on dormant buds in spring (MacAloney and Ewan 1964). During the growing season, larvae bore in the current year's shoots, often killing them and preventing terminal growth. Frass, which is ejected from the galleries, is mixed with webbing to form shelters around the entrances. When terminals are killed, opposite lateral shoots begin elongating and often produce forks or other deformities. Larval entrance holes are typically present near the base of current season's growth. When an infesation is sufficiently severe, trees become bushy and disfigured (MacAloney and Ewan 1964). Large trees have been so heavily injured in early summer in West Virginia that they appeared to have been damaged by heavy frost. In the Pacific Northwest, 7 to 50% of bigleaf maple seeds have been destroyed by this borer. Boxelders planted in nurseries and shelterbelts and as ornamentals are often heavily infested in the northern Great Plains, as is sugar maple in the northern Great Lakes area (MacAloney and Ewan 1964).

Range: Transcontinental in distribution across the northern United States and south to Mississippi (Furniss and Carolin 1977, Powell 1962). Discontinuously distributed across Canada, from Nova Scotia to southern Alberta (Prentice 1965).

Synanthedon acerni

Hosts: Silver maple is preferred; red maple and sugar maple are readily attacked, and other maples are probably susceptible. Mountain-ash has been listed as a host (Beutenmuller 1901), but this record needs to be confirmed

Round exit holes 3 to 4 mm in diameter in bark typically adjacent to wounds are good evidence of infestation. Brown frass, mostly consisting of small excrement pellets, may be visible at wounds, in bark crevices, or in other rough areas of the bark (Beal and others 1952, MacAloney and Ewan 1964). Borers are found most frequently at the boundary of live callus tissue and dead areas in scars and wounds on the trunks and large branches of ornamentals. Once infested, even minor wounds are kept from healing properly, and heavy infestations can enlarge wounds. Repeated attacks can cause disfigured, gnarled areas on the bark that sometimes ruin the appearance of ornamentals (Felt 1905). Infestations are sometimes recognizable by empty pupal skins sticking out of the bark. Open or loose bark at branch crotches and around pruning wounds may indicate attack. Feeding on the inner bark and sapwood, the larvae, once established, attack year after year, leading to a gradual decline of the tree (Engelhardt 1946). Trees may be girdled or killed by the burrows or weakened so that they are more susceptible to decay and wind damage (Holland 1968). The injuries cause deformities and unsightly scar tissue, sometimes resulting in serious defects in forest stands (Beal and others 1952).

Range: Occurs in Canada, New England, mid-Atlantic region, Midwest, the Mississippi River Valley south through Mississippi (Engelhardt 1946), and west to Nebraska (Holland 1968). 

The poplar leafcurl midge, Prodiplosis morrisi Gagné, is a native North American cecidomyiid fly that lays its eggs on developing cottonwood terminals. The larvae feed on surfaces of expanding leaves, causing them to curl into elongated, largely cylindrical shapes. Leaves may stay green with only curled edges turning brown, or leaf may be killed.

Pulvinaria innumerabilis (Rathvon) 
COTTONY MAPLE SCALE 

Hosts: Silver maple, honeylocust, hackberry, linden and other hardwoods. 

Cottony maple scale is one of the largest and the most conspicuous scale insect that occurs in the region. Adult females may swell to over 1/4 inch diameter when producing a large cottony egg sack. Adults and nymphs feed on plant sap of twigs and leaves, respectively.

Cottony maple scale also excretes honeydew as it feeds. 

The cottony maple scale spends the winter as adult, mated females on twigs and branches. During winter they appear as small, indistinguished dark lumps but begin to grow rapidly when they resume feeding in spring. A very large, wax-covered egg sack is ultimately produced by late spring, somewhat of the appearance of a marshmallow, and may contain over a thousand eggs. Eggs hatch from late June through July and the newly hatched crawlers settle on the undersides of leaves, usually near the midrib. During this leaf-feeding stage the nymphs are flattened with oval form and nearly translucent.

Nymphs feed on leaves until late summer, migrating to twigs and small branches before leaves drop. They then molt for the last time, after which the females remain in place for the rest of their lives. Males are produced at this time which are mobile and mate with the females, dying afterwards. There is one generation per year. 

Parthenolecanium (= Lecanium) corni (Bouche) 
EUROPEAN FRUIT LECANIUM (Brown Soft Scale)

Hosts: European fruit lecanium has a very wide host range including many deciduous trees and shrubs. Elm and stone fruits (Prunus) are the most common hosts. 

European fruit lecanium is a soft scale that feeds on the phloem of small branches. European fruit lecanium is also capable of producing large amounts of honeydew, which can be a serious nuisance problem and favor the growth of sooty mold.

Coinfestations with other scales can occur, particularly mixed populations with European elm scale. The European elm scale can be identified by having a covering that is dome-shaped, dark brown, and fairly smooth. 

Eriosoma lanigerum (Hausmann)

Hosts: Apple, crabapple, mountain-ash, elm 

The more severe injury is caused by the insect feeding on the roots of apple, crabapple, and mountain-ash, resulting in large knots (galls) on the roots. Heavily infested trees often have short, fibrous roots, and are stunted and sometimes killed. Callous tissue around aboveground wounds are also commonly infested, which inhibits healing and can produce cankers.

A small, delicate fly. Damage is caused by larvae which feed between the upper and lower layers of leaves. Two to six larvae typically occur in a single leaf. With a little practice, they are easily found by breaking open a blistered leaf with your thumbnail. 

Zeuxidiplosis giardi
Hosts
St. Johnswort (Hypericum perforatum)

Description
Larvae are orange and can reach up to 2mm in length, completing three instars. Adults are very small (3 mm long) and have dark red bodies and gray heads, wings, and legs.

Life Cycle
Larvae emerge in early spring and feed on leaf buds, causing leaves to grow into a spherical gall that is green with reddish markings. Larvae feed at the base of the gall; pupation occurs inside. Adults are sexually mature upon emergence and live for only 5 days. There may be up to 7 generations per year, though there are usually fewer than 5. Larvae and pupae overwinter.

Impact
Larval feeding and galling lead to stunted plant growth and occasional death, though it is not as effective in the western U.S. as other agents.

Availability
Limited availability from California and Hawaii.

... Author: Rachel Winston, Mark Schwarzlander. University of Idaho Extension.

Spruce Broom Rust (Chrysomyxa arctostaphyli)

Compiled by Ned Tisserat, Colorado State University:

Host
Several species of spruce (Picea species): primarily affects Engelmann spruce (Picea engelmannii) and Colorado spruce (Picea pungens) in the [High Plains] region. Requires alternate host in the genus Arctostaphylos including kinnikinnick (bearberry) and manzanita.

Symptoms
This rust causes conspicuous, perennial witches’ brooms, which bear annual, yellow-green needles. Spermagonia appear in summer as small reddish eruptions that release a putrid odor detectable from several meters. Broom needles appear yellow-orange in mid-summer when spore (aecial) pustules are formed. These brooms may be mistaken for those caused by dwarf mistletoes; however, in spruce, only spruce broom rust causes a marked loss of chlorophyll and annual casting of all broom needles. On the lower surface of the leaves of the alternate host, telia appear as localized reddish-brown spots.

Impact of Disease
Damage caused as a result of this broom rust includes reduced growth, stem deformation, dead tops (spiketops), and tree mortality. Breakage may occur at the point of stem infections, which act as infection courts for decay fungi.

Life Cycle of the Pathogen
The fungus lives systemically and perennially in both hosts and may overwinter in either host. In spruce, buds and emerging twigs are infected in the spring by spores produced on the alternate host, and the fungus invades the young shoots and induces the formation of witches' brooms. The rust produces five types of spores of which two, spermatia and aeciospores, are produced on current year’s needles of true fir; the others are produced on the alternate host.



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