Lichens on Trees

A few days ago a gardener proclaimed to me that an expert had told her that Lichens are found only on trees that are no longer growing. I don’t know what expert might have told her that but I’m sure she misinterpreted whatever may have been said.

Lichen growing on young crab apple tree.

The study of Lichens is a huge branch of Biology in and of itself. People who take an interest in that field of study often become quite rabid about the subject. I’ve been on expeditions where the Biologist talked as if the world existed for the sake of providing a place for Lichens to grow.

Lichens are actually a combination of two organisms, a fungus and an algae. They work together as one in order to survive in places where they couldn’t otherwise. The algae provides energy through photosynthesis while the fungus provides shelter and a place for the algae to live.

They can be found covering a wide variety of objects in addition to trees including rocks, roofs, bare soil and just about any other exposed surface.

On trees Lichens are harmless. They are actually quite attractive on trees adding an extra visual element to the landscape. Many gardeners will go to extreme lengths to get Lichens established on certain features in their garden. Lichens growing on the roof, on gravestones or other unwanted places is a whole different subject that we won’t cover here.

As for the gardener who thought that Lichens can be found only on non-growing trees, all she has to do is look in her own yard to see that Lichens are quite happy on actively growing trees.


Apple Codling Moth

Growing good apples is a little tricky because of all of the pests that feed on them and cause damage to the fruit.

We discussed the Curculio a couple of posts ago, this time we need to talk about another major pest on apples, the Codling Moth.  This is the proverbial “worm in the apple” that you see in those old-timey cartoons. It is not a worm as such but rather is the larva of a moth.

The Codling Moth is not a very attractive moth as seen in this photo taken by MSU Horticulturists.

Normally there are two generations of this pest in our area although in some years we see a third generation as well depending upon that season’s weather.

According to scientists who measure certain weather and other conditions, the Codling Moth larvae are hatching from their eggs right now.  After the larvae hatch, they will begin to burrow into the fruit.  Once they get inside the fruit they cannot be killed because  insecticides cannot reach them.

Codling Moth damage on apple. (MSU photo)

Timing is very critical for controlling Codling Moth effectively since the larvae begin to burrow into the fruit just hours after hatching. Large commercial orchards use sophisticated traps to monitor adult moths. With that information they can determine when egg laying happens  and apply their sprays accordingly.  For the rest of us we have to pretty much rely on our 10 day to two week spray schedule to do the trick.

Michigan State University Extension in Van Buren County has a very detailed web page regarding this pest.

Another generation of Codling Moth can be expected in August.



I decided to expand our vegetable garden this year by converting some of the wild area behind the existing garden into usable garden space.

While tilling and planting I found these subterranean dwelling insects known as “wireworms”.

You can see by the photo how they got their name, they sort of look like a piece of copper wire and have a hard, shiny exterior skin.

Wireworms found in the garden.

They are actually the larval form of the “click beetle”. These are beetles that make a “click” when they flip themselves up onto their  feet if they some how ended up on their back.

There are several species of wireworms out there and are commonly found in newly tilled sod, like my area, or in gardens that have not been weeded very thoroughly.

There  are also species that prefer garden crops, the potato is especially vulnerable to wireworm attack. Damage in potatoes shows up as reduced yield caused by the larvae  chewing on the roots and as holes burrowed into the potato tuber itself.

Years ago there were many insecticides that would eliminate wire worms in the garden, those have all been taken off the market due to environmental concerns.  Your best bet to reduce wire worms in the future  is to keep your garden free of weeds throughout the gardening season. There are also some biological products on the market that show some promising results in keeping wire worms in check.

Keeping wireworms away is another good reason to keep that garden weeded!


Insect Attack on Fruit Trees

Back in May I wrote about the need for early sprays for your fruit trees and how critical those early sprays are. If you didn’t take my advice, you may have noticed some of the fruit on your trees have marks on them caused by insects.

These developing fruits are the first casualties of the battle against the bugs.  They have been attacked by the Plum Curculio. Notice the vaguely  crescent- shaped blemish on the skin of the fruit here on the photo.

Typical symptoms of Plum Curculio damage.

The adult beetle looks for fruit into which it hopes to lays its eggs.  She burrows out a small cavity into the surface of the fruit then turns around and lays an egg into the cavity.  She then chews that tell-tale crescent around the newly hatched egg.

This pest infests most fruit trees grown in our area including (in order of preference) nectarine, plum, cherry, peach, apricot, apple, pear, and quince.

Most of the time the damaged fruit falls off of the trees but sometimes the fruit continues to hang on in the case of  peaches and cherries.

In two weeks time after feeding on the fruit, the larvae mature and emerge from the fruit to enter into the soil where they pupate for a couple of weeks. Then about 5 days from maturity, the beetles are back to infest more fruit. They continue this life-cycle all season long until October.

So even though it is too late to save the fruit that was attacked in this first wave, you should still keep a 7-10 day spray schedule going to control this and other pests.

Our next enemy that will be attacking the orchard is the Apple Maggot, they are poised to attack very soon.  We’ll discuss that next time.


Still Time for Planting

Did you spend a lot of productive time in your garden over the Memorial Day weekend, or did you go out to the lake?  I hope you got a chance to do both, that’s what we did.

Memorial Day  is the target date for getting gardens planted here in southeastern Michigan.  I’m guessing that a vast majority of gardeners got their gardens planted over the holiday  weekend.

Don’t worry too much if you didn’t get a chance to plant yours, there is still time to get your plants into the garden and end up with a harvest in the fall.  I still have much more to plant since I am expanding our garden somewhat this year.

Sunflowers such as these can still be sown directly into the garden.

A list of vegetables that I might seed directly into the ground would include green beans (and other beans as well), beets, cabbage, carrots,  sweet corn, cucumbers, melons, squash, pumpkins, and watermelon.

Plants that can be set out as transplants from the greenhouse or garden center include tomatoes, peppers, brussels sprouts, eggplant, onions, and sweet potatoes.  Plants listed in the direct seed list are also available as started plants, the exceptions being carrots, beans and sweet corn.

There are also flower seeds that can still be sown directly into your garden including cosmos, blanket flower, four o’clock, gailardia, sunflower, zinnia and many others. There are many, many varieties of  flowers  available as started plants too.

Later on in the season we can sow seeds of certain plants for a fall crop of cool weather vegetables. We’ll discuss that as we approach that date.