Author Archives: John Valo

Brown marmorated stink bug (Halyomorpha halys)

Photo by Alfredo Colon

Brown marmorated stink bug (Halyomorpha halys) is an exotic, invasive, true bug. It is native to China, Japan, Korea, and Taiwan. It was accidentally imported into the United States, probably in shipping crates or on machinery. It was first collected in Allentown, Pennsylvania in September 1998, but by then there had already been several sightings. Since its introduction in the U.S., the brown marmorated stink bug has spread rapidly. It now occurs in the east from Maine to Minnesota, south to Florida and eastern Texas, and in the west from northern Washington to southern California. Between these areas there are many scattered sightings and a few expanding populations around the larger metropolitan areas.

Brown marmorated stink bug is a voracious eater. It damages fruits and vegetables, causing pitting or scarring on the outer surfaces. It also damages ornamental crops, causing small, ⅛″ (4 mm) in diameter stippled areas around feeding sites. It is considered an agricultural pest. It feeds on and causes damage to a wide variety of crops, including apples, apricots, Asian pears, cherries, corn (field and sweet), grapes, lima beans, nectarines and peaches, peppers, tomatoes and soybeans. The wounds it creates can be an entryway for diseases to attack the plant.

Brown marmorated stink bug is also a nuisance to humans. In early fall, it begins looking for a place to spend the winter. It frequently finds its way into people’s houses. Often, an individual is found near a window or door, which is its original entry point. Large congregations may be found hiding under furniture like bookcases, beds, or sofas, or under or behind baseboards.

Adults are variable in size, ½″ to ⅝″ (12 to 17 mm) in length. The body appears broad-shouldered and somewhat shield shaped. The color is also variable, usually brownish gray but sometimes brownish yellow, grayish brownish-yellow, orangish brown, or chestnut brown. The entire body is densely covered with tiny dark pits.

Emerald ash borer quarantined in Minnesota

emerald ash borer
Photo by Babette Kis

On November 1, 2023, the Minnesota Department of Agriculture declared a quarantine to prevent the further spread of emerald ash borer. It prohibits the importation of firewood and other regulated articles into the state, and the movement of those articles from quarantined areas to uninfected areas.

Emerald ash borer, also known by the acronym EAB, is an exotic, invasive, small to medium-sized, metallic wood-boring beetle. It is native to northeastern Asia, including China, Mongolia, North and South Korea, Japan, Taiwan, and far eastern Russia.

Emerald ash borer was first detected in North America in 2002 in Detroit Michigan. It was probably imported in the wood of a shipping crate in the late 1990s. It has spread rapidly since its introduction. It now occurs from Maine to northern Georgia, west to Minnesota and northeastern Texas. It was discovered for the first time in Minnesota on May 14, 2009, in South Saint Anthony Park in St. Paul. It is now common in southeastern Minnesota, and it is continuing to spread in the state.

Emerald ash borer larvae feed exclusively on black ash, green ash, and white ash. They feed on the inner bark (cambium), creating serpentine tunnels (galleries) that interrupt the flow of food. They eventually girdle and kill the branch or tree. They have killed millions of trees in the eastern United States, including over five million trees in a 3,000 square mile area of Michigan.

Adults are active in Minnesota from May 1 through September 30. They are found in deciduous forests and woodlands, in parks, and in urban and residential areas, anywhere ash trees are found.

On October 8, 2003, the USDA Forest Service imposed a quarantine on emerald ash borer. It prohibited the interstate movement of all firewood and other regulated items out of infected areas. The USDA removed the quarantine effective January 14, 2021. An emerald ash borer female can fly up to 100 miles in her lifetime. The quarantine had not been effective in preventing the spread of the beetle into adjacent areas.

The Minnesota Department of Natural Resources estimates that there are nearly a billion ash trees in the state. Infected forests dominated by black ash will become grasslands, brushlands, or marshes. City budgets will be strained by the costs of removing dead trees from their streets.

The Minnesota quarantine will remain in effect until cancelled.

Ailanthus webworm moth (Atteva aurea)

Ailanthus webworm moth
Photo by Babette Kis

Ailanthus webworm moth (Atteva aurea) is a small, native, ermine moth with a colorful appearance and an unusual history. It was formerly native to the tropical Americas, including southern Florida, Central America, and the Caribbean, where its larval hosts were paradise tree (Simarouba glauca) and Simarouba amara. In 1784, the Chinese tree of heaven was introduced into Philadelphia. The tree was fast growing and spread quickly. When it reached Florida in the 1850s, ailanthus webworm moth found it to be an acceptable host. The moths then began moving north to wherever their new host was found.

Ailanthus webworm now occurs throughout the United States east of the Great Plains, and in southern Quebec and Ontario Canada. It is common in the eastern United States, uncommon but increasing in Minnesota. Tree of heaven, which is often planted as an ornamental in urban areas, remains the primary larval host, but larvae have also been found on avocado, Emory’s crucifixion-thorn, and sumac. Adults are found visiting flowers from May to October in Minnesota. They can’t survive northern winters, but they recolonize the northern range of tree of heaven every year. Although its range has recently expanded greatly, ailanthus webworm moth is not considered invasive by any state or province.

Adults are 7⁄16″ to ⅝″ in length and have a 11⁄16″ to 13⁄16″ wingspan. The forewings are reddish-orange with four broad black bands filled with white or pale yellow spots of varying size. The bright pattern is thought to be a warning to predators of their unpalatability. The black areas have bluish-purple reflections. The hindwings are mostly translucent with black on the margins and black veins.

Powdered Sunshine Lichen (Vulpicida pinastri)

Powdered Sunshine Lichen
Photo by Alfredo Colon

Powdered Sunshine Lichen (Vulpicida pinastri) is an easily recognized, widespread, and very common lichen. It occurs in northern forested areas around the globe, including Europe, Asia, and North America. It grows on the bark of conifers and birch. It is usually found no more than chest high, probably protected under snow from desiccation by winter winds.

The vegetative body is leaf-like and divided into lobes. When growing on flat surfaces, the lobes are short, and it forms a flat rosette. When growing on thin branches, the lobes are longer and more erect. The upper side is greenish-yellow or yellowish-green in sunny locations, grayish-green in shaded locations. The margins are densely covered with bright yellow reproductive granules, giving them a powdered look. This is the feature that gives the lichen its common name.

Bulbous Honey Fungus (Armillaria gallica)

Bulbous Honey Fungus
Photo by Honey Fae (Farah)

In the early 1990s a huge underground mycelium of Bulbous Honey Fungus (Armillaria gallica) was found covering 37 acres in the Upper Peninsula of Michigan. Molecular genetics showed the underground part of the fungus (mycelium) to be about 1,500 years old. It came to be known as the “Humongous Fungus”, became a popular tourist attraction, and spawned a annual fungus festival. At the time of its discovery it was thought to be the largest organism on earth, a title formerly held by Pando, the quaking aspen grove in Utah. Since that time, three other organisms have held that title. The current (2022) holder is the marine plant Posidonia australis in Shark Bay, Australia.

Bulbous Honey Fungus is a common, late season, gilled mushroom occurring in Europe, Asia, and North America. It appears in late summer and fall growing on the ground attached to underground roots, on stumps and logs, and on the base of living trees.

The mature cap is broadly convex to almost flat, pinkish-brown or brownish-yellow, and covered with slender fibers. The stalk is thick and expanded at the bottom, appearing club-shaped. The flesh is edible when cooked and has a mild to bitter taste.

Dusky slug (Arion subfuscus/fuscus)

Dusky slug
Photo by Greg Watson

Dusky slug (Arion subfuscus/fuscus) is common, exotic, terrestrial slug. It is native to northern Europe and was introduced into North America in the vicinity of Boston in 1842. By 1940 it was widespread across North America. It is found in moist or wet areas in deciduous and coniferous woodlands, in meadows on rocks, and in old fields and waste places. It is often encountered in areas of human activity, including in roadsides, gardens, campgrounds, wood piles, and window wells. In natural areas it is sometimes more abundant than native snail and slug species. It can a pest of agricultural crops, forest replantings, and gardens.

Two species of dusky slug are often treated as a single species complex, a group of species so similar that the boundaries are unclear. Aside from their geographic distribution, the two species can only be distinguished by the size and color of the genitalia of dissected individuals, or by analysis of their alloenzymes. Both species have been introduced into North America.

Adults are long and slender when extended, short and bell-shaped when contracted. The body is covered with rows of pale bumps, giving it a finely granular appearance. It is variable in color, but populations generally fit into one of four color groups: blackish-brown, yellowish-brown, orange, and reddish-brown. The orange or yellowish-orange color is mostly – or completely – due to a covering of mucus. When handled, the mucus will stain the handler’s fingers. There is usually a brown stripe on each side.

Great pond snail (Lymnaea stagnalis)

Great pond snail
Photo by Luciearl

Great pond snail (Lymnaea stagnalis) is a very large, air-breathing, freshwater snail. It is commonly sold as an aquarium pet. The body contains both male and female reproductive organs (hermaphroditic). During copulation either the male role or the female role can be performed, though not both. This makes it the ideal subject for recent scientific research into handedness (chirality).

Great pond snail occurs in Europe, Asia, North America, and southern Australia. It occurs throughout the United States and Canada, but it is uncommon south of the 40th parallel. It is common in Minnesota. It is found in permanent, slow or still waters, usually with dense vegetation, including creeks, streams, rivers, marshes, swamps, and reservoirs, and at the edges of lakes and large ponds.

The shell is thin and has 4½ to 6 whorls. The last whorl is the body whorl and is greatly inflated. The remaining whorls are elevated forming a sharply pointed spire. When seen with the tip at the top and the opening facing up, the opening is on the right side. There is no door-like structure covering the opening of the shell. The shell is variable in color, tan to dark brown, and it has no obvious markings. A cavity within the shell has an air bubble that is refreshed every time the snail rises to the water surface to breathe.

Horned spanworm moth (Nematocampa resistaria)

Horned spanworm moth
Photo by Babette Kis

Horned spanworm moth (Nematocampa resistaria) is a small geometer moth. It occurs across the United States and southern Canada. In the U.S. it is common east of the Great Plains and in the northwest but is rare or absent elsewhere. Adults are found from early June to late September in deciduous and mixed forests and woodlands, in meadows, and in parks.

Female forewings are whitish or cream-colored with reddish-brown lines and veins, numerous short horizontal lines, and a purplish-brown patch on the inner half of the wingtip. The hindwing is similar, but the entire tip of the wing is dark. The male is similar but smaller, is usually yellowish, and there is a dark brown blotch at the tip of the wing.

The adult sometimes rests on the upper side of a leaf, where it resembles a dead leaf; on the underside of a leaf, where it resembles a dead patch; or on leaf litter on the ground, where it blends in with the background.

Horned spanworm moth
Photo by Alfredo Colon

The caterpillar is up to ¾″ long and is instantly recognizable. The ground color varies from yellow to brown and is heavily mottled with brown. On each of the first and second abdominal segments there is a pair of curled, extendable, white-tipped tentacles (filaments).

The caterpillar often rests on an upper leaf surface with the body looped. It has been suggested that this mimics a fallen flower and its stamens. When alarmed, it inflates the filaments to twice their length.

Ruby Bolete (Hortiboletus rubellus)

Ruby Bolete
Photo by Holly Stanger

Ruby Bolete (Hortiboletus rubellus) is a small, red capped, blue staining mushroom. It occurs in Europe, the United States, southern Canada, and Mexico. It reaches the western extent of one part of its range in eastern Minnesota. It is found in summer and fall in woodlands, parks, and gardens. It grows on the ground near oaks and other hardwood trees.

The cap is small, no more than 2⅜″ in diameter, and is bright but dark pinkish-red. This is the feature that gives the mushroom its common name. It often has a thin yellow or whitish band around the margin. The pore surface on the underside of the cap is yellow. It quickly stains dark blue when bruised. The stalk is up to 2¾″ long, is mostly red, and has many tiny red dots. When cut lengthwise, the flesh of the stem reveals numerous, tiny, bright red or carrot orange dots near the base.

Ruby Bolete is edible but it has a soapy taste, and like other boletes, it is often infested with maggots.

Blue stain fungi

blue stain fungi
Photo by Honey Fae (Farah)

There are between 100 and 250 species of sap staining fungi, and they are divided into three groups. One of these groups is known as blue stain fungi. It is an informal grouping of various species of sac fungi (Ascomycota) that cause blue discoloration in the heartwood of trees without destroying the wood. The fungi are from the genera Ceratocystis, Ophiostoma, Ceratocystiopsis, and Grosmannia. They do not form a single taxonomic group because they do not descend from a common ancestor. Not all species in those genera cause blue staining.

Blue stain fungi spores are carried to a living tree on the body of a wood boring beetle. Their thread-like cells (hyphae) produce dark melanin on their walls to protect them from light, drought, and the tree’s own defenses. Blue discoloration spreads from the wound on the outside through the heartwood in a wedge-shaped pattern following the spread of the fungus. Boxelder trees produce a brilliant red stain in the wood as a response to the fungus.

Blue stain fungi damages the living tree by clogging the vascular system, leading to decline and premature death of the tree. The damage caused to the wood is merely aesthetic. The discoloration makes the wood undesirable and less profitable but does not weaken the wood.