The Yellow Farmhouse Garden

January 12, 2016

Bitter pit spots on apples in storage

Filed under: Disease,Fruit — bob @ 2:15 pm

One of our goals in gardening is to grow as much as we can for Thanksgiving and Christmas dinner, I bet you do that too. Even if we end up with only enough servings for just Thanksgiving dinner, I call it a successful harvest.

Judy needed to come up with a dessert for Thanksgiving this year so she decided on homemade-from-scratch, gluten-free apple cobbler. Of course you need apples for apple cobbler so I went to my storage bin for the apples.

They were not the pristine apples I usually have, these were covered in small, unsightly spots. I’ve seen those symptoms before in years past. They had  ”cork spot” sometimes called “bitter pit”.

To me, cork spot is a more accurate description than bitter pit. For one thing, apples don’t have a pit, they have an apple core. The other reason is because of the corky appearance and texture of the affected area. On the other hand, the spots do have a bitter taste, so “bitter pit” works too.

The corky spots develop just under the skin of the apple.

The corky spots develop just under the skin of the apple.

Some scientists separate bitter pit and cork spot into two different disorders with the difference being the timing when the spots show up. If they show up before harvest, it is cork spot. If it develops in storage they call it bitter pit. Either way it is not caused by any disease organism or insect.

Even though the disorder may not show up until Thanksgiving time, it has its beginning way back during the growing season when the apple was still on the tree. As the apple grows, there is some competition for water between the developing fruit and the growing leaves. That water competition may cause a calcium imbalance which weakens the cell wall in the fruit leaving it open for the symptoms to develop.

Pruning, of course, has a big effect on the number of leaves on a tree. So the proportion of apples to leaves can be different from year to year.

Rain or lack of it determines the amount of soil moisture available and that can change almost weekly during the growing season. So it is a complex set of events that contribute to the problem which is why you may not see it every year in your home grown apples.

Improper storage will often lead to bitter pit. In my case, I’m guessing it was because I did’t get the apples into storage quickly enough. That can cause the spots to show up before you have a chance to use the apples.

I had a few different varieties of apples in storage and some apples had spots and others didn’t — some varieties are more prone to bitter pit than others.

The corky texture of the spots made it much harder to peel the apples. Also, I ended up with smaller pieces because I had to cut away the affected area to get rid of the bitter taste.

Judy’s apple cobbler turned out great and was a big hit at the dinner, you couldn’t even tell it was gluten free!

I spared everyone from the convoluted story about the apples and their bitter pit spots.

Bob

 

 

 

 

September 4, 2013

Corn smut — huitlacoche

Filed under: Disease,Vegetables — bob @ 12:50 pm

While picking my sweet corn this year, I’ve noticed a higher than normal amount of ears with corn smut growths.

Corn smut is a fungal disease that infects all types of corn but sweet corn is most susceptible to it. The fungus invades the corn tissue and causes the corn plant to form a gall-like growth. We usually see these growths on the ears of the corn but they can also occur on the tassel and other parts of the plant.

It’s just about impossible to eliminate corn smut. The fungus can live year after year in the garden soil and will reinfect a sweet corn crop each season. Plus the spores of the fungus is easily carried by the wind from infected plants.

There is no spray or seed treatment for this problem. The usual control suggestion is to cut out the infected plants and burn them before the smut has a chance to form spores.

This year however, I’ve decided not to fight corn smut but instead embrace it.

Corn smut tastes much like mushrooms.

South of the border — I mean Mexico, not Ohio — corn smut is a delicacy. Since smut is a fungus, it is used much like mushrooms which are fungi too. Some people call it Mexican truffle, in Mexico it’s called huitlacoche. Mexican farmers, instead of destroying the infected plants, harvest the growths and sell them at a premium price.

My huitlacoche is forming spores so, it is past its prime for eating.

My corn smut is past its prime — it’s filled with dried spores — so I didn’t have chance to try it yet. I have one more crop of sweet corn coming on and I’m looking forward to my huitlacoche harvest!

Bob

August 31, 2010

New Threat to Walnut Trees

Filed under: Disease,Insects,Trees — bob @ 9:08 am

Another potential disease problem is over the horizon threatening our local trees.  This time it is the Black Walnuts that are at risk.

A fungal infection called Thousand Cankers has been killing Black Walnut trees in the western part of the United States for several years.  It has been confined to nine states in the Rocky Mountain area and westward until July of this year. Its range seemed to be associated with a different walnut called the Arizona Walnut.  Black Walnut is not native to that particular area but was brought in and planted by arborists, landscapers and others.

This summer it was confirmed that the disease had spread to at least one location in the Eastern USA,  Knoxville Tennessee.  Scientists now believe that it may have been present there for a number of years without anyone knowing about it.

At this time Thousand Canker disease is NOT present in Michigan.

The disease is caused by a fungus which is carried by a very tiny beetle called The Walnut Twig Beetle.  Despite its name the Twig Beetle  attacks larger branches or even the trunk of Black Walnut Trees by tunneling under the bark. They leave small “galleries” or tunnels in the wood caused by the beetle larvae feeding there.

When the larvae mature into adults they emerge from the branches out of small holes chewed through the bark. The fungus then infects the damaged area and causes a small lesion or “canker”.  These cankers spread very fast and merge together eventually moving from the outer bark into the cambium layer.  Each branch has a tremendous number of cankers which is how the disease got its name.

The cankers themselves are often difficult to see and identify.  A special lab test is needed for positive identification.

There is no cure or control for either the Twig Beetle or Thousand Cankers, plant pathologists are working on that though.

In the meanwhile we can help slow down the spread of this problem by not moving firewood just like we do to prevent Emerald Ash Borer from spreading.

There is no federal quarantine on moving wood products but the State of Michigan has issued its own quarantine against shipping articles made of wood from certain western states.

The USDA Forest Service has a good publication on this problem.

As I mentioned earlier, Thousand Cankers is not present in Michigan at this time. Keep in mind that there are a lot of other things that can cause a tree to show signs of  die-back  other than this disease.

Bob

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