Tips about some fungus among us

April 11, 2019

Morel mushroom hunting season is coming up and people are being advised not to harvest mushrooms from areas affected by flood waters. Flood waters contain contaminants like E. coli, other bacteria, chemicals and more.

Some mushroom hunting areas are still under water or beneath sediment deposited by flood waters. However, in areas that flood waters covered but mushroom hunting is or will be possible, it is best to err on the side of safety and not harvest and eat mushrooms from flood affected areas this year.

You may have seen the information that says garden produce that comes into contact with soil can be harvested after 120 days from gardens affected by flood waters. This recommendation does not apply to morel mushrooms.

Morel mushrooms porous and fragile structure would make it difficult, if not impossible, to adequately clean them; or to cook them to high enough temperature to kill bacteria.

While on the subject of fungus, I’ll talk about a few others that are plant pathogens. The time period for applying fungicides to control some diseases is fast approaching and it’s time to get prepared.

While most fungi are harmless or serve important roles such as helping to break down organic matter, some are pathogens and cause plant diseases.

With new plant growth soon to begin, fungicide applications may be needed on susceptible fruit trees, pines and spruce; but only if these plants had a disease issue last season.

Most foliar fungicides work by preventing infection. To effectively reduce a disease, they need to be applied before the pathogen infects the leaves.

Many fungal spores also require moisture on a leaf surface for infection to take place. Because of the frequent rains we had last summer, there was an increase in fungal infections on susceptible plants.

If you had a fruit or evergreen tree infected by a foliar disease last year, and you choose to use fungicide control, the time to apply it to prevent or reduce infections this year is just as new leaves begin to grow.

Susceptible cultivars of fruit trees, especially apples and crabapples susceptible to cedar apple rust and apple scab, may need to be sprayed. If your fruit trees showed no signs or very limited signs of disease last season, it does not need to be sprayed.

If the fruit tree spray used contains both a fungicide and an insecticide, remember not to apply the product while the tree is blooming to protect pollinators.

Pine and spruce trees also have issues with fungal diseases, most commonly Sirrococcus shoot bight and Rhizosphaera needle cast. With increased moisture last season, we are seeing an increase in these needle blights.

If a pine or spruce has browning of needles towards the lower half of the tree, needles with reddish spots or bands or black specks, this could be one of the needle blights.

If an evergreen is known to have a fungal disease, fungicides labeled for us on evergreens need to be applied just after the new needles begin to emerge in spring to prevent new infections. A second application needs to be made in 7 to 10 days or according to label directions.

Kelly Feehan is a community environment educator for Nebraska Extension-Platte County.