Leafy mistletoe can often have just green stems or reduced leaves growing in arid regions. This is Phorodendron densum with small leaves growing on Arizona Cypress.
Galls on trees are made up of disorganized cells and can be very dense. They can be made into very interesting and beautiful objects for display.
Heterobasidion irregulare fruiting bodies at base of tree. This pathogen has recently been found in southeastern Minnesota and is expected to spread as it has done in Wisconsin. WI DNR reports 28 counties in Wisconsin with Heterobasidion Root Disease. Be on the lookout for this pathogen in Minnesota.
Petri dishes and bags of bioluminescent fungi glowing in the lab. Armillaria, a root rot pathogen, has mycelium that glows in the dark.
A pine board with white pocket rot. These interesting white rot fungi have the ability to selectively degrade lignin leaving cellulose behind. Some fungi, such as Porodaedalea (Phellinus) pini, produce small spindle-shaped white pockets while some other white pocket rot fungi produce much larger zones of delignification.
Blue stain fungi impart dark discoloration to wood from their pigmented hyphae. Blue stain can lower the quality of wood used for wood products but in some cases, such as this turned pine bowl, it can add value.
Zone lines or pseudosclerotial plates are made up of fungal melanin that acts to separate incompatible white rot fungi from each other. Often called spalted wood, it is used by woodworkers and artists to make interesting objects.
As you eat the Pleurotus, remember meiosis has occurred in the basidia and those gills are filled with hundreds of thousands of extraordinary basidiospores.
Pleurotus ostreatus fruiting to the size of dinner plates! And these will end up on student's dinner plates
Second successful production of Pleurotus this semester - isolated, grown in pure culture, inoculated into spawn, inoculated into bags and fruited.
Aecia on the bottom surface of a hawthorn leaf caused by Cedar-Hawthorn Rust, Gymnosporangium globosum.
Juniper broom rust with telia coming out of the branches. The telia produce basidiospores that infect serviceberry (Amelanchier)
Fusiform rust with pycnia oozing pycniospores. This sweet liquid attracts insects that move the pycniospores from one pycnium (+) to another of an opposite mating type (-).
Aecia of white pine blister rust on an infected white pine. The aecial stage is only seen in a 1-2 week period around the beginning of June. This blister-like aecia give the disease its name "blister rust".
Lophodermium has long, thread-like ascospores with a sticky sheath that helps adhere them to needles after they are ejected out of the hysterothecium.
Lophodermium on old pines needles showing black hysterothecia. These black fruiting bodies open producing ascospores from the compressed apothecium that is under the black stromatic material.
The Synnemata of Ophiostoma novo-ulmi with spores masses of asexual spores can be beautiful but this fungus packs a powerful punch and is responsible for killing hundreds of millions of elm trees in the United States.
A red oak infected with oak wilt the previous year will produce oak wilt mats under the bark the following year. In spring, the pressure pads break open the bark and the aromatic fungus attracts Nitidulid beetles. The photo shows the pressure pads of the fungal mat when the bark was pulled off. These mats would be full with conidia and if both mating types are present, perithecia will also form.
What fungus do you think caused this type of canker on this ash tree?
Spring infection of oak with oak anthracnose when leaves are just forming can mimic the symptoms of oak wilt. However, there are ways to differentiate oak wilt from oak anthracnose. Can you determine this?
This homeowner asks "Will my maple tree die?" Maple anthracnose can cause problems when we have a wet spring. Do trees die from anthracnose?
The mushroom-like fruiting body of a pink Pleurotus. This fungus would be classified in the Basidiomycota and produces basidia and basidiospores on its gills.
An example of a fungus in the Ascomycota. This cup-like fruiting body produces asci and ascospores. It is called the witches cauldron and is a rare and endangered fungus found growing in spruce bogs.
These maple leaves have a problem. Can you determine if this is caused by an abiotic or biotic agent?
Keeping forest and urban landscape trees healthy requires a good knowledge of tree diseases. This class will provide you with important information you can use in the future. Watch this page for new photos each week.