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Posts Tagged ‘Plant Diseases’

Happy first day of summer! Our local weather forecast calls for temperatures in the md 90s with high humidity, so I’ll be staying in the shadier parts of the forest. What follows are a few things that can be found there. This eastern tiger swallowtail butterfly (Papilio glaucus) looked as if something had been taking bites out of its trailing wing edges. It was resting in the shade on a false Solomon’s seal plant and didn’t bat a wing while I was taking pictures. Do birds chase butterflies and take bites out of their wings? I thought these common split gill (Schizophyllum commune) mushrooms were bracket fungi because, even though they are one of the most common mushrooms, I hadn’t ever seen them. They are found on every continent except Antarctica and don’t grow there only because there is no wood for them to live on. Though they look like a bracket fungus they are mushrooms with torn and serrated gill-like folds that are split lengthwise. These mushrooms dry out and re-hydrate many times throughout the season and this splits the gill-like folds, giving them their common name. These ones looked like fuzzy scallop shells. I did see bracket fungi though. These turkey tails (Trametes versicolor) were surrounded by moss. I had to wonder if the moss was winning the battle. This eastern painted turtle (Chrysemys picta picta) was in the middle of the path I was on, quite far from water. He (she?) looked like he couldn’t decide whether to go into or come out of his shell.  After a few pictures I left him just the way I found him, thinking he would reach a decision quicker if I wasn’t there watching him. He was about the size of a soccer ball. I saw plenty of little brown mushrooms.  Even mushroom experts have trouble identifying these mushrooms and recommend that mushroom hunters stay away from any that are small to medium size and are brown, grayish brown or brownish yellow.  The deadly skullcap (Galerina autumnalis) is a little brown mushroom, and it wouldn’t be a good day if it were accidentally eaten. Many cherry trees have nipple or pouch gall on their leaves this year. These are small finger like nubs on the leaf surface caused by tiny eriophyid mites laying eggs on the leaf.  The mites secrete a chemical substance that causes the leaf to expand over their eggs. When the eggs hatch the baby mites feed inside the finger shaped gall. The galls caused by these mites don’t hurt the trees and are seen as a natural curiosity. Over time the galls turn from green to red and when the leaves drop in the fall the galls drop with them. Thorns on a native black locust (Robinia pseudoacacia) tree. These are nowhere near as dangerous looking as the thorns on a honey locust tree, but I still wouldn’t want to accidentally run into them.  Farmers have used black locust for fence posts for hundreds of years because it is dense, hard, and rot resistant. It is said to last over 100 years in the soil. Black locust is in the pea family and is considered toxic. This tree was growing at the edge of the forest. Several together would make an impenetrable thicket. Native Deer Tongue Grass (Panicum clandestinum or Dichanthelium clandestinum) seems to be thriving this year.  I like the way the leaves look as if they have been pierced by the stem. When they do this it is called clasping the stem. Many plants-the common fleabane for example-do this. This grass prefers moist soil and plenty of sun. Deer Tongue Grass is just starting to flower. Native Porcupine sedge (Carex hystericina ) is another plant that likes moist soil and full sun and I usually find it growing near ponds and streams. It is also called bottlebrush sedge. The green prickly looking flowers are called spikelets. Both male and female flowers are on each plant. Waterfowl, game birds and songbirds feed on sedges seeds. The Sedge Wren builds its nest and hunts for insects in wetlands that are dominated by sedges. The color of these new maple leaves was beautiful enough to deserve a photo, I thought. It is amazing how many plants have new leaves that start out red or maroon before turning green. Since chlorophyll is what makes leave green, this tells me that the emerging foliage doesn’t have much of it. The pussytoes (Antennaria) in my yard have all gone to seed. The yellow hawkweed (Hieracium caespitosum) is also going to seed. Each plant can produce as many as 500 seeds in a single flower head. This plant is native to Europe and is considered a noxious weed.Way down at the bottom of the spathe, or pulpit, at the base of the spadix called Jack, the fruits of Jack in the pulpit (Arisaema triphyllum ) have been forming. Soon these immature green berries will begin to swell and will turn bright red. The seeds in the berries are more often than not infertile. Those in the photo are at a stage that most people never see because the wilted spadix is usually covering the immature fruit. I peeled parts of it away to get this picture. Doing so won’t harm the plant. These tiny green flowers of the wild grape (Vitis species) don’t look like much but they are very fragrant. I smelled these long before I saw them and followed their fragrance to the vine. The flowers are so small that I can’t imagine what insect pollinates them.

In the woods we return to reason and faith~ Ralph Waldo Emerson  

I hope you enjoyed seeing what the woods here in New Hampshire have to offer. Thanks for stopping in.

 

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Note to Readers: I’m sorry if you have been wondering why I didn’t do my regular Saturday morning post this week, but I did and it didn’t “stick.” Did I not press “publish?” Maybe it was because it was 4:00 am and I did it in my sleep-but no-that’s the way they’re all done.  Anyhow, here it is. NHG

It was the third week of March but if I didn’t know better I would have bet it was mid-June. This day was the fifth hot, dry one in a record breaking week. I decided it might be cooler if I took my afternoon walk in the evening instead, but I was wrong. 

The sun was setting fast but it was still hot-over 80 degrees. The failing light formed pools of gold on the stream and throughout the forest. This stream feeds into a large marsh.

On the edge of the marsh speckled alder’s male catkins glowed in the last rays of sunshine. Alders like plenty of water and sunshine and they find it here. 

Alder bushes were silhouetted against the glow on the surface of the pond away from the setting sun. This small pond is near the marsh and holds its overflow. One evening I watched two beavers that live in the marsh swimming here. The red winged blackbirds always put up a fuss when I wander around this area.

I walked around to the sunny side of the pond to get a better view of the marsh, only to find that the sun was almost gone. Still, I thought I might have time for another picture or two. I know shooting into the sun isn’t a good idea, but I wanted to catch the colors before it went down completely.

 Here alder tongue gall grows on the alder’s female seed bearing cones, called Strobiles.  Many galls are caused by insects, but alder tongue gall is caused by a fungus (Taphrina alni). The fungus chemically deforms parts of the female cone-like catkins and causes long tongue shaped galls, known as languets, to grow from them.

I was surprised that the beavers hadn’t bothered the alders, but it didn’t take long to find out why. This was a clump of birch trees just 4 days earlier, and now it’s a clump of stumps. Because of the golden light and bleeding sap you wouldn’t know the bark on these stumps was white.

Soon the buds on the blackberry will break and leaves will hide its thorns. These very spiny canes help keep kids from getting too close to the edges of the pond and marsh.

I thought I might see some Red Winged Blackbirds in one of their favorite dead trees but apparently they only use it when I’m not pointing a camera at them. Once the spring peepers started singing their evening song I knew it was time for me to head home. 

Thanks for visiting.

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I can’t think of another shrub that can claim more striking fall colors than the common blueberry (Vaccinium.) Even after 18 inches of snow and several nights of below freezing temperatures this one hung on to its leaves. A shaft of bright sunlight on a cloudy day made it seem as if it was lit from within. Finding such a healthy bush told me that the soil here is most likely a highly acidic, well drained sandy loam.

 

I had been having a lot of ear trouble and then one day I noticed this maple tree with an old wound that looked very much like an ear. Was it a sign? An interesting fact about trees is that their wounds do not heal like ours do. Instead they are covered over by callus tissue that develops at the edge of the wound and gradually grows inward toward the center. You can actually see  how that process takes place in the photo above. While the wound calluses over the tree uses built in natural resistance to fight off insects and disease. This is such a large, deep wound though, that the tree might lose the battle. Wounds like this are excellent points of entry for fungal diseases like those of the turkey tail fungus, below.

 

I found this bracket (shelf) fungus called turkey tail (Trametes versicolor) growing on an old hemlock stump. This fungus is considered a mushroom and is very common.  It is also the bane of the forestry industry because it causes heart or sap rot in trees and is the kiss of death; once the fungus attacks a living tree it cannot be stopped, and the tree will die.  On the brighter side, turkey tails have been found to contain a carbohydrate (Polysaccharide-K) that is used in Europe and Japan for the treatment of many types of cancer. Turkey tail is said to biodegrade some types of pollutants and is a favorite food of fungus moth (Nemaxera betulinella) caterpillars.

 

 The pointy clusters of red berries (drupes) of the Staghorn Sumac (Rhus typhina) can be seen everywhere at this time of year. They are an important winter emergency food for many types of birds including Robins, Evening Grosbeaks, Bluebirds, Cardinals, and Scarlet Tanagers. After a thorough soaking and washing, the berries were made into a drink resembling pink lemonade by Native Americans. In the Middle East they are dried and ground into a lemon flavored spice.

 

Lichens grow on a Northern Red Oak (Quercus rubra). Lichens are actually a symbiotic relationship between a fungus and algae or a fungus and bacteria. The fungus, which doesn’t have the ability to produce chlorophyll by photosynthesis, relies on the algae or bacteria, which do produce chlorophyll, for food.  Unlike the bracket fungus, they don’t usually harm the trees that they grow on. Lichens are very sensitive to pollutants, so when they are seen in great numbers in an oak grove it means the air quality is good. Many animals feed on lichens and some birds use them for nest building.

 

The large growth on this Black Cherry (Prunus serotina) trunk is a burl. A burl is a growth defect caused by insects, a virus or fungus, or an injury. Most burls grow underground on a tree’s roots but they can also be found above ground like this one. Inside a burl the grain is twisted, interlocked, and very hard and forms figural patterns that are highly prized by woodworkers, furniture makers, and artists.  This burl, larger than a basketball, could be worth hundreds of dollars or even more depending on the grain pattern.  Museum quality bowls made from burl are rare and can fetch thousands.

All of these things were seen within a half mile of my house. Why not see what nature has to offer near yours?

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You could see a witches’ broom this Halloween, but you don’t have to look for a wart nosed hag wearing a pointy black hat to find one.

Witches’ broom is a plant deformation which appears as a very dense cluster of branches, often found on woody plants like trees and shrubs. Blueberry bushes for example, often have witches’ brooms. I know of one bush that I picked berries from for years that had a large broom growing in the center of it. The growth didn’t seem to inhibit berry growth or affect the plant in any way. In fact, it looked as healthy as the bushes that surrounded it.  

In some cases however, as in rice, the fungus that causes witches’ broom can be fatal. In other instances plants act positively bewitched; potatoes with witches’ broom can form tubers on top of, rather than below ground. This isn’t much help for the farmer when you consider that potatoes exposed to sunlight become toxic by forming solanine, which is a poisonous alkaloid.

Witches’ brooms are usually caused by either a rust fungus or a parasitic plant such as mistletoe, but there is an aphid known to cause honeysuckle witches’ broom, and on hackberry trees (Celtis occidentalis) it is caused by both a powdery mildew fungus and a tiny mite. On cherry and blackberry it is caused by bacteria carried by insects from elm or ash trees.

In the case of blueberry bushes, witches’ broom is caused by a fungus that lives on balsam fir trees. This broom fungus always needs a blueberry and a fir as hosts and is very specific; a blueberry with the fungus can’t infect another blueberry. Most brooms caused by rust fungus need two host plants. The fungus that causes witches’ broom on balsam fir needs common chickweed as a secondary host, and the fungus that infects spruce needs the lowly bearberry (Arctostaphylos uva-ursi).

Witches broom can cause very desirable dwarfism and increased branching in some plants. In fact, many well known dwarf evergreen shrubs are the result of witches’ broom.  For example, Montgomery Dwarf Blue Spruce is one of the best dwarf blue spruces, and is from a witches’ broom. Globosum, a round-headed, grafted form of Japanese black pine, is the result of a witches’ broom.  Another black pine, Hornibrookiana, will be no larger than 6 feet across and 2 feet tall even after 30 years, thanks to a witches’ broom.

So if you should see a witches’ broom on Halloween or at any other time, remember-it is not the home of hobgoblins and witches and is not a Hexenbesen (bewitched bundle of twigs) as medieval writers would have you believe.  No-more than likely it is, once again, just nature doing what it does so well.

 

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Powdery mildew is a caused by any one of over 1600 species of fungus and makes leaf surfaces appear as if they had been dusted with gray or white talcum powder. Most species of fungi that cause powdery mildew are host specific, which means the mildew on your lilacs won’t attack your squash. The fungus produces mycelium (fungal threads) that grow on the surface of the plant but don’t invade the tissues themselves. Fungi feed by sending haustoria, or root-like structures, into the epidermal (top) cells of the plant.

Powdery mildew thrives when days are warm and dry and nights are cool. Cool, shaded areas where air circulation is poor and humidity is high are perfect breeding grounds, so susceptible plants should be planted in full sun far enough apart for air to circulate freely around them. Powdery mildew does not need a wet leaf surface to grow, but overhead watering raises humidity and can splash spores from infected plants to healthy plants, so watering should always be done from below, as with a soaker hose. Applications of high nitrogen fertilizer in late summer should be avoided because mildew prefers young, tender growth.

I have phlox and lilac that get infected each year but still bloom well the following season, so I don’t get overly concerned with powdery mildew. As an experiment, this year I planted a mildew resistant variety of tall phlox called Blue Boy, which so far hasn’t shown any signs of mildew. Pruning a few stems from the center of non resistant plants with dense crowns will increase air circulation.

The fungus does far more damage to vegetables than ornamentals and can spread quickly through squash, melon, and cucumber beds.  Planting mildew resistant varieties and pruning infected leaves from plants at the first sign of infection will go a long way in controlling the fungus.

Sprays can also be used for prevention and control. Studies by scientists in Brazil show that a spray made of 1 part milk to 9 parts water reduced the severity of powdery mildew infection by 90% on squash plants. Weekly applications have been shown to work well.

Another spray is made by mixing 1 tablespoon of baking soda, 1 tablespoon of vegetable oil, and 1 tablespoon of liquid dish soap in 1 gallon of water. Spray weekly, preferably on overcast days to avoid burning leaves.

Neither of these sprays will kill existing powdery mildew, but they will prevent its spread.  The disease can complete a cycle in as little as 72 hours, so it is important to inspect plants regularly and begin spraying at the first sign of infection.

Since the fungus over-winters on plant debris and in dormant bud scales, sanitation is an important part of control. All infected plant debris should be removed from the garden in the fall and destroyed. Never put infected plant debris in a compost pile.

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