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Posts Tagged ‘cedar apple rust’

Spindle galls on cherry

Galls on plants are funny things.

They come in all sizes, funky shapes, and crazy colors. There are thousands of different types of galls and they can be caused by insects, fungi, bacteria, mites, midges, or wasps. Galls can form on the leaves, buds, flowers, stems, twigs, branches, and even on roots.

Oak bullet galls

Oak bullet galls

Normally, galls are formed by the plant in response to some type of “alien invasion”; often from insect or mite feeding or egg laying. As bizarre as these abnormal growths appear, they do not usually interfere with the normal function of the plant.

A few years ago I wrote about two types of galls that are common on goldenrods; the bunch gall caused by the larva of a small gnat and the stem gall caused by the larva of the goldenrod gall fly. The goldenrod was still blooming and seemed otherwise unaffected despite the presence of these galls.

Oak trees seem to harbor several different types of galls, many of which are caused by tiny gall wasps.

Oak bullet gall with exit hole

Oak bullet gall with exit hole

This spring when I was walking around in our yard, I noticed a bunch of hard, round galls on some low branches of a young white oak tree. These galls are called oak bullet galls (or oak marble galls) and are caused by a gall wasp. The gall forms as a deformity of a leaf bud when the wasp lays an egg within the leaf bud tissue. The developing larva stimulates the growth of the gall which starts out as a round green mass and matures to a hard brown marble-sized gall later in the summer. The tiny adult wasp emerges in September through a small exit hole in the gall.

Oak apple gall developed from this oak leaf tissue

Oak apple gall developed
from this oak leaf tissue

 

Oak bullet galls are often confused with another common oak gall called the oak apple gall. Oak apple galls are quite a bit larger than the oak bullet galls. They too are caused by the feeding of a gall wasp larva. In this case, the gall actually develops from leaf tissue.

Like most galls, oak bullet galls and oak apple galls do not usually hurt the tree.

 

Wool sower galls are quite beautiful!

Wool sower galls are quite striking!

 

The wool sower gall is another strange gall that is only found on oak trees and specifically only found on white oaks. These puffy, round galls are caused by the larvae of another small wasp. They are really cool looking! Wool sower galls are sometimes called the oak seed gall because if you tease them apart, you will find tiny structures that resemble seeds in the center. The wasp larvae develop in these little compartments.

Spindle galls on a cherry leaf

Spindle galls on a cherry leaf

Another really funky looking gall is the spindle gall. Every year I see these weird growths on the leaves of some of the wild cherry trees in our woods. Talk about something out of a sci-fi movie! These colorful, finger-like galls are caused by microscopic mites called eriophyid mites. The galls form in early spring when the leaves begin to expand and the tiny mites begin feeding on the leaf tissue.

Spindle galls on a maple leaf

Spindle galls on a maple leaf

The upper surfaces of the leaves become covered with these crazy looking pink, red, or green spindle-shaped projections. It looks like some terrible rash! Believe it or not, the growth of these spindle galls has little effect on the health of the trees. Spindle galls are common on maples as well as cherries.

Galls caused by one of the spruce gall adelgids

Galls caused by one of the
spruce gall adelgids

Adelgids are devastating pests of many conifer species. Woolly adelgids have decimated huge populations of Eastern hemlocks and Fraser fir in the eastern part of the United States.

Several adelgid species, including the eastern spruce gall adelgid and the Cooley spruce gall adelgid, produce galls in various species of spruce. Unlike the woolly adelgids, these adelgids generally do not kill the trees unless there are repeated infestations which can eventually weaken the trees. Normally the damage is limited to the tips of a few branches, but in the landscape, these brown tips can be unsightly.

A mature cedar-apple rust gall erupts into mass of bright orange tendrils after wet weather in the spring.

A mature cedar-apple rust gall with bright orange tendrils

Cedar-apple rust is a fungal disease that produces weird galls on eastern red cedar trees. I’ve written about this double-host disease before. During wet weather in the spring, these galls sprout gelatinous tendrils full of fungal spores which are carried to the alternate host, apple or crabapple trees. Here they cause damaging rust disease on the leaves and fruit. The galls on the cedars cause little damage to those trees but the apple and crabapple trees can be heavily damaged if they are not protected with fungicides.

 

Well – that’s a little bit about some of the funky growths that you may encounter in your landscape!

Normally, chemical control is not warranted or even very successful with these galls, EXCEPT in the case of the adelgids and the cedar-apple rust. Adelgids can be controlled with Bonide All Seasons Oil and the cedar-apple rust can be controlled on apples and crabapples with Bonide Copper Fungicide.

Until next time – Happy Gardening!

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Cedar apple rust on young apples

Well, it’s been quite a year so far.

We have had so much rain that it has been hard to get anything done in the garden. One day in June at our house we got 4¾” of rain from 3 separate “cloudbursts” that occurred within 6 hour period. Our driveway was a river and was washed out in several places. We were very lucky that the vegetable garden didn’t wash away that afternoon but thanks to a berm of juniper branches and the ditch that Eric dug last year, it was mostly spared!

Brown rot has already destroyed many of the peaches.

Brown rot has already destroyed
many of the peaches.

Unfortunately, the orchard isn’t looking very promising this year. Most of our weekends this spring were either rainy or too windy to spray the fruit trees and boy does it show! Last year we had a great crop of apples because I was able to spray All Seasons Oil and copper fungicide as needed.

This year disease is the main problem. The wet, humid weather has really promoted the development and spread of disease in the orchard as well as in the flower gardens and the vegetable garden. Spraying with a fungicide would have helped to some extent but conditions have been so favorable this year that I feel that disease problems were inevitable!

A stinkbug on one of the peaches. Clear, sticky gum on the surface of the peach shows where they were feeding.

A stinkbug on one of the peaches. Clear,
sticky gum on the surface of the peach
shows where they were feeding.

A few weeks ago I was dismayed to see that brown rot had already consumed some of the peaches and others were beginning to show signs of infection. On top of that, stinkbugs were crawling over the peaches causing damage to fruit that was otherwise still healthy! Everywhere they had punctured the skin of the peach, a blob of sticky goo had formed in response to the injury caused by their feeding.

Rats – there goes my peach crop for this year.

The grapes and apples are having their own disease issues with the appearance of black rot on most of the grape clusters and rust on the apples.

The older cucumber leaves were riddled with a fungal disease.

The older cucumber leaves were
riddled with a fungal disease.

In the vegetable garden, my cucumbers began developing spots on the older leaves which I think is anthracnose or possibly downy mildew. I was in panic mode then – everyone is counting on getting some pickles this year!

All of these diseases develop rapidly and spread readily in the moist, humid conditions we’ve been experiencing this season. It seems like we’ve had rain nearly everyday lately!

Many of the fungal diseases in the garden can be reduced by practicing good sanitation during the season and in the fall. I know I say this a lot but it is really important to rake up and remove all dropped leaves, fruits, and cuttings from the garden. This plant debris is full of fungal spores which can infect new growth as the season progresses or reinfect plants when they emerge the following spring. This is especially important in the vegetable garden and in the orchard.

Grape mummies must be removed from the vine to reduce infection next season.

Grape mummies must be removed
from the vine to reduce infection
next season.

This means all those little grape mummies and all the peach and plum mummies must be removed from the trees (or vines) and bagged up. All the ones that have fallen to the ground must be carefully raked up and removed along with all the fallen leaves. In the early spring, prune out any twigs and branches with cankers and thin the trees and grape vines to increase air circulation and reduce humidity around the plants. Quite a job but well worth it in the long run.

What I did with my cucumbers was to remove all the diseased leaves and then spray the plants with Bonide Copper Fungicide. This should help control the spread of the disease to the healthy leaves. That was a two weeks ago and they are still looking good thank goodness!

Diseased lower leaves on my cucumbers.

Diseased lower cucumber leaves.

Cucumbers after diseased leaves were removed.

After removal of diseased leaves.

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To help control disease (and many insect pests), clean up the vegetable garden at the end of the season. Rake up and remove any diseased plant material. If you are able, be sure to rotate your crops the following season.

Another way to reduce disease in the garden is to plant disease resistant varieties whenever possible. There are many new cultivars and hybrids of trees, shrubs, perennials, annuals and vegetables that show resistance to many of the common fungal diseases.

Until next time – Happy Gardening!

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Peach totally engulfed by brown rot

Believe it or not, I followed my own advice this weekend!

All Seasons Oil will smother the overwintering egg cases of tent caterpillars.

All Seasons Oil will smother the egg cases of tent caterpillars.

I sprayed my fruit trees with Bonide All Seasons Oil. I have mentioned in many of our February and March newsletters and advised countless garden center customers that a late winter/early spring application of horticultural oil is one of the most important sprays to protect your fruit trees. It’s important because it smothers insect eggs (like tent caterpillar eggs) and overwintering insect pests (like codling moth larvae, mealybugs, and scale) by forming a coating of oil over them. It can also smother fungal spores and reduce the incidence of certain fungal diseases like rust or powdery mildew.

But have I ever sprayed it in our little orchard? No – at least not until this year! If it’s so important, why didn’t I do it? Well, my excuse was that whenever I had “time” to spray, the wind was blowing too hard or it was raining or I didn’t have the spray on hand or I missed the timing or …

Mealybugs cause damage to foliage and fruit.

Mealybugs cause damage to foliage and fruit.

In all honesty, it was more because it was so much trouble to mix up enough spray to cover all the fruit trees. Our little hand sprayer had to be refilled several times by the time we were finished. A few years ago, we got a backpack sprayer that held more and I used it for a while but even that had to be refilled quite a few times to cover all the trees and I never did manage to get that initial spray of horticultural oil on the them.

This year for an early birthday present, we bought ourselves a 16 gallon sprayer that can sit in the trailer we pull behind our mower. Best of all, it has a 12 volt pump that is powered right from the mower battery! Wow! I can tell that this new sprayer is going to revolutionize our fruit growing just like Uncle Bill’s old Troy-Bilt tiller revolutionized my vegetable gardening.

Brown rot ruins my peach crop.

Brown rot ruins most of my peaches before they have a chance to ripen.

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The sprayer is made to attach to an ATV but Eric built a frame out of treated lumber that holds the tank and keeps it from moving around in the cart. Perfect!

We tried it out with the All Seasons Oil this weekend and it worked like a charm! We made up 9 gallons of spray which was the perfect amount to cover all the trees. So quick and easy!

I’m determined to keep up with the spraying this year so maybe we’ll get some fruit that we won’t have to share with the bugs and diseases!

Brown rot on a plum

Brown rot on a plum

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At the top of my list is battling brown rot on our peaches. Every year, because I haven’t sprayed a fungicide, we watch as our peaches (and plums) become swallowed up by this dreaded disease. Brown rot is a common fungal disease that affects stone fruits like peaches, plums, apricots, and cherries. It can be devastating to a fruit crop and can destroy most or all of the fruit on a tree in a relatively short period of time.

Mummified peaches hang from one of my peach trees.

Mummified peaches hang from one of my peach trees.

Sanitation around the trees is one of the most important ways to try to reduce the incidence of this disease (and many other fungal diseases that affect fruit trees) because the fungal spores overwinter in plant debris and on mummified fruits that hang on the tree and fall on the ground. Even with careful cleaning and raking, treatment with fungicides is often necessary to help control brown rot especially if the disease has infected your trees in the past. To be most effective, it is very important to begin spraying for brown rot before infection occurs.

More information about brown rot

Black rot beginning to infect grapes.

Black rot beginning to infect a
bunch of grapes.

So … this weekend we’re going to fire up the sprayer again (weather permitting) to spray Bonide Liquid Copper fungicide on the trees and our grapes.

Bonide copper fungicide is a broad range fungicide approved for organic gardening that will help control a host of diseases in our orchard including brown rot on the peaches and plums, black rot on our grapes, and cedar-apple rust which affects our apples every year even though we have planted resistant varieties.

Cedar-apple rust infects some young apples

Cedar-apple rust infects some of
our young apples

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I really think we’ll be able to keep up with the insects and disease this year! We’re even thinking of getting a two more peach trees and maybe another plum!

Now I’m just hoping that we don’t get a late frost that wipes out the blossoms!

Here’s to a “fruitful” year!

Until Next time – Happy Gardening
and Happy Spring!

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I have cedars and I have apples …

not a great combination if you want healthy apple trees!

A mature cedar-apple rust gall erupts into mass of bright orange tendrils after wet weather in the spring.

A mature cedar-apple rust gall erupts into mass of bright orange tendrils after wet weather in the spring.

The other day as I was driving to work, I noticed those dreaded bright orange growths clinging to the branches of many of the cedar trees in the area. Some trees had quite a few of these odd looking structures on them. They look like something out of a sci-fi movie with their fleshy, neon orange “tentacles” protruding out of and completely covering a hard kidney-shaped mass.

What are they?

These funny-shaped growths are the galls of cedar-apple rust, a fungal disease that requires two hosts to complete its life cycle; Eastern Red Cedar (Juniperus virginiana) and the alternate hosts, primarily apples and crabapples (Malus spp.).

This cedar apple rust gall has released its spores already and the tendrils have shriveled up.

This cedar apple rust gall has released its spores already and the tendrils have begun to shrivel up.

The brown galls which form on the cedar branches begin the cycle. When they mature after about two years, they “sprout” gelatinous orange tendrils during rainy weather in the spring. These tendrils release fungal spores which infect the leaves and twigs of susceptible apple and crabapple trees. After the spores germinate, the fungus grows causing yellow spots and rusty lesions on the apple leaves. Eventually in the late summer, these lesions produce spores on the underside of the leaves. These are the spores that will re-infect the cedar trees to start the cycle over again.

Cedar apple rust spots on the leaves of a hawthorne. Courtesy of Missouri Botanical Garden Plant Finder.

Cedar apple rust spots on the leaves of a hawthorne. Courtesy of Missouri Botanical Garden Plant Finder.

Cedar-apple rust normally doesn’t affect the health of the cedar trees beyond some dieback on the branches where the galls are growing. It’s the apples and crabapples that get the raw end of the deal. With severe infections, much of the leaf surface can become covered with the rusty spots. This can inhibit photosynthesis and also result in premature leaf drop. Eventually the tree may weaken and could even die.

We actually had a McIntosh apple tree succumb to cedar-apple rust a few years ago. When we first planted our apple trees, we knew that we would have a problem with cedar-apple rust because of all the red cedars that surround the property so we specifically chose cedar-apple rust resistant varieties: Liberty, Freedom, Jonafree, and Macfree. We got the McIntosh on a whim one year and this poor tree was always so covered with rust that it looked like it had orange fall foliage in the middle of summer. I probably could have helped it by spraying a fungicide but I never seemed to get around to it …

Cedar-Quince rust is another dual host fungal disease associated with Eastern Red Cedar.

Cedar-Quince rust is another dual host fungal disease which is associated with Eastern Red Cedar.

What can you do?

You can prune out the galls that appear on the cedars and junipers in your landscape but this really isn’t very effective because like pollen, the fungal spores can travel for long distances on the wind and your apples and crabapples could still be infected from cedars located miles away.

The best solution is to plant resistant varieties of apple and crabapples. There are loads to choose from. Andre has compiled a list of his favorite disease resistant crabapples.

Cedar-apple rust infects some young apples

Cedar-apple rust infects some
young apples

If you have existing trees that are susceptible to rust, you can apply an appropriate fungicide to reduce the incidence of the disease. It is critical that the fungicide is applied before the tree is infected which means spraying should begin as soon as you see the fleshy tendrils growing from the galls on the cedars. Once the symptoms appear on the apple trees, fungicides will not be effective. When the tendrils on the galls have shriveled up and dried, fungicide applications are no longer necessary.

Suggested fungicide is Bonide Liquid Copper. Always read and follow the label directions and if spraying fruit trees be sure the fungicide is listed for use on fruits and vegetables.

Until next time – Happy Gardening!

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