Photos of the Week

 

white pine blister rust

Aecia of white pine blister rust is found on infected white pines in late may to early June in Minnesota. These spores infect currents and gooseberries.

 

When mature and released from the hysterothecia, the long thin ascospores have a sticky sheath that helps them adhere to needles.

The ascospores of Lophodermium as seen under the microscope. The spores are long and tread-like with a sticky sheath that helps adhere them to needles after they are ejected out of the hysterothecium.

Asexual stage of Ophiostoma

Synnemata are produced by the fungus causing Dutch elm disease on dead elms. Sticky spores are produced on the top of the packed columns of conidiophores (black stalks) and elm bark beetles pick up the spores and bring them to new elms when they maturation feed on elm twigs and stems.

ded_campus_before

The University of Minnesota St Paul Campus before Dutch elm disease started to take its toll. Big elms lines all the campus streets. This picture shows where the buses stop outside of the student center.

newman canker

What fungus do you think caused this canker on ash?

 

maple anthracnose

This homeowner asks "Will my maple tree die?" NO! - not if the tree just has maple anthracnose

Anthracnose on oak after early spring infection. Symptoms can look like a wilt disease.

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?

 

Pleurotus Basidiomycota

A fruiting body of Pleurotus (the pink species). This is an example of a fungus in the Basidiomycota. The gills contain basidia and basidiospores.

basidia and basidiospores

Sectioning a gill shows basidia with 4 basidiospores on each basidium.

 

red pines

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.