New Threat to Walnut Trees

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.


Parasitized Tomato Hornworm

There seems to be an abundance of Hornworms in the garden this year.  A couple of posts ago I discussed picking the pests off of the plants by hand as one way of controlling them.

This morning while picking even more Hornworms off the tomatoes, I came across one that I though you should see. It had been parasitized by a small insect  known as a braconid wasp.

These tiny wasps  fly around the garden looking for likely victims. When they find a suitable host, they sting the caterpillar and lay their eggs inside its body.  The eggs hatch and the larvae feed on the innards the worm.  As the wasp larvae near the pupation stage, they chew through the caterpillar’s skin and spin small white  cocoons made of silk which remain stuck on the surface of their host. The cocoons are sometimes mistaken for eggs by some gardeners.

This Hornworm has 3 or 4 dozen cocoons on its back. Each cocoon contains one wasp that will emerge and begin hunting more caterpillars to parasitize.

Days later the new fully-developed adult wasps will emerge from the cocoons and  fly off to find new caterpillars to parasitize.  Needless to say the caterpillar does not survive the procedure, which is good news for us gardeners.

The adult flying wasp does get hungry but does not eat caterpillars instead it feeds on nectar from flowers

If you find a caterpillar with these cocoons on its body, leave it undisturbed where you found it so that you will have dozens more helpers in the battle against the Tomato Hornworm.


Blackberry Jam

We”ll be finishing up the last of our wild blackberry jam this week… making it not eating it.

One batch of blackberry jam.

Our blackberries have been producing quite well for a number  of weeks now. We only have a few plants but as long as we keep picking them, it seems like they keep on producing.

You need to pick this many berries for one batch of jam which will give you ten half-pint jars.

In our little corner of the township we have been experiencing a mini-drought, so the berries are not as large as they usually are. Even so, we’ll have nearly 50 half-pints of blackberry jam made up to give out as Christmas presents this year.

If you or someone you know is out of work and out of money and is worrying about what they’ll give for Christmas to all of the extended family members, I suggest you think about making some jam or jelly to give away as gifts. It really doesn’t take much of an investment in cash, it just takes some time.

Perhaps you don’t have  berry plants of your own, ask around maybe somebody has a berry patch that they will let you pick from.  There are also pick-your-own farms within reasonable driving distance from anywhere in Michigan.

Blackberries are winding down in our part of the state but blueberries are still going strong and we have raspberries and grapes to look forward to as well.

Never made jam or jelly before? It’s pretty easy to do all you need is fruit, sugar, pectin and a few jars from the grocery store. Then just follow the simple directions that comes along with every box of fruit pectin.

Even if money is tight, by making jelly or jam, you’ll have much of your Christmas list taken care of early this year.

Bob and Judy

Tomato Blight

By now if you have tomatoes in your garden, I’m sure you have been seeing leaves that have started to turn yellow and develop spots.  These are symptoms of any one of three fungal diseases that infect tomato plants in our area; Early Blight, Late Blight and Septoria Leaf Spot.  They are often referred to by many gardeners as just “Tomato Blight”.

Early Blight spots usually form concentric rings as the spots get bigger.  Late Blight Spots have less distinctive borders and often look watery, while Septoria Spots appear smaller and separated.

Blight on my tomato plant, can you guess which one it might be?

Early Blight and Septoria are the most common and  show up very frequently  in tomatoes, so much so that many gardeners accept this as a normal part of tomato growing.  Late Blight is a much more serious infection.

Late Blight and Early Blight will infect the fruit as well as the leaves while Septoria will cause reduced yields and damage from sun scald due to lack of leaves available for photosynthesis and to protect the fruit from the direct rays of the sun. Late Blight can be particularly damaging as it can kill an entire garden full of tomatoes in 10 days if the weather conditions are right

The treatment is about the same for all three diseases: spraying the plants with a fungicide.  The treatment will not “cure” the disease but will help keep the symptoms from progressing further. Be aware that you need to be vigilant in applying your fungicides if you decide to spray.  Rotation of your planting from year to year helps somewhat if you have the space to do so.  Dead and dying plants should be removed and bagged up and be sent to the landfill along with your regular trash to avoid spreading the diseases.

Michigan State University has a good Fact Sheet that discuses these diseases in more detail.

These Blights will also infect Potatoes which belong to the same plant family as  tomatoes.


Tomato Hornworms Are Back

The week before last I saw the first few Tomato Hornworms in our garden. I was able to take care of them pretty quickly by picking off the first two or three.

Today they came back with a vengeance.  I found Hornworms all over our tomatoes. Here’s the first batch I “harvested” from the plants:

The first batch of today's Tomato Hornworms.

There are a few alternatives  you can use to get rid of Hornworms these include spraying chemical or biological insecticides, applying  insecticidal dusts or picking them off by hand, the method I prefer.

Whichever method you choose, do it quickly. They can grow from cute tiny caterpillars that hardly make a mark on a leaf to monsters like these  in just a few days. Once they reach this size, they can literally devour an entire plant overnight.

If you decide to use the hand pick method, here’s a tip that will help you find them.  Since Hornworms’ camouflage is so effective, they can be very difficult to detect. Go thorough your plants and pick off the ones you see right away. Then go do something else in another part of your garden for a while, even ten or twenty minutes will do.  This gives your eyes a chance to “re-set”.  When you come back to look for the worms, you can often spot the ones you missed the first time through.

It also helps to check them a couple times throughout the day. As the light changes, you may be able to spot the rest of them that are hiding.

In my first time through my plants I found this batch of worms.  After about a half an hour, I found eight more in the same spots I looked at the first time around!

You may be wondering what I was going to do with a bowl full of Tomato Hornworms. I took them over to our chickens and tossed the worms  in one at a time. This provides loads of entertainment for both the chickens and myself.  The chickens like to play several games with the worms like “Chicken Football” and ” Chicken Rugby” and my favorite “Tug of War”.

To avoid a lot of  disappointment,  check those tomato plants as soon as you can… before you head out to the beach.