Out-of-control fungi that kill entire populations across a wide geographic area are usually viewed with utter horror: late blight on our garden tomatoes and potatoes and the white-nose syndrome that kills bats come to mind as recent examples. But Entomophaga maimaiga, a fungus that kills gypsy moth caterpillars, and – thank goodness – only those of the gypsy moth, has… (more)
When an insect develops on a single host, and kills the host in the process, it is called a parasitoid. Parasites, on the other hand, tend to nibble on their hosts without killing them. And predators kill more than one of their prey items. Because most parasitoids spend much of their lives buried within the bodies of their victims, they… (more)
On a walk through a still, snowy sugarbush, the peacefulness can be overwhelming; everything looks to be in good order. But all may not be as perfect as it seems. In any sugarbush, there is a good chance that a fungal intruder has gained entry and is wintering unseen beneath the rich, dark bark of an unlucky sugar maple. If… (more)
Wily, non-native plants that outperform native species and proceed to carpet the forest and field are all too familiar nowadays. Most of us have seen understories of European buckthorn or Eurasian honeysuckle species where normal tree regeneration doesn’t stand a chance. The wild chervil, garlic mustard, and wild parsnip introduced from Europe seem to have supernatural powers as they march… (more)
Most loggers are well aware of the perils of blue stain. If freshly cut logs are left for any length of time in the summer months, one of the many species of fungus that leave bluish streaks in the wood is sure to invade the logs, dramatically reducing their value. White pine and sugar maple are among the most vulnerable… (more)
An apple orchard in late May, just as the trees’ deep pink buds expand into pale pink blossoms, is one of the most beautiful places on earth. I won’t tell about the smells or the songs of birds to further describe this heaven, because this story is about fire blight, a bacterial disease that first strikes right at this magical… (more)
Crown gall, the common name for Agrobacterium tumefaciens, is one of the most famous plant diseases in the world. This bacterium can cause galls in more than 600 plant species, some of which are trees. Members of the rose family, including apples, pears, peaches, and cherries, are especially susceptible; willows and poplars are also vulnerable. Vineyards can be troubled by… (more)
Although apple scab is everywhere all the time, it is most apparent in the fall, as we try to avoid apples spotted with its telltale, ugly, black lesions. Those spots, it turns out, were predetermined in the spring. In order for the apple scab fungus to get a start, the leaf surface needs to be wet. Since spring is a… (more)
If, when quietly wandering around outdoors, you have ever heard and tried to track down a rhythmic, grating sound, thinking you were in search of a small rodent or perhaps a cricket, only to find that the noise comes from within a dead log, the noisemaker might well be the larva of the whitespotted sawyer. Its chewing noise is described… (more)
Also called birch bracket, this distinctive fungus only grows on birches, looks like nothing else that grows on birches, and is very common. Also in its favor from the human perspective is that it is not an aggressive tree killer, but is instead primarily in the business of decomposing dead trees. Birch polypore is present throughout the range of the… (more)