![]() So traditional breeding followed by backcrossing is underway, primarily by The American Chestnut Foundation ( TACF). But Chinese chestnut is not such a great tree – it is short and spreading instead of tall and straight, with less desirable timber and fruit characteristics. Resistance can slow the fungus down and limit its reproduction. The fungus causes persistent perennial cankers rather than diffuse cankers. But there are some areas of hope for some form of recovery.īreeding for resistance. We will never have chestnut like we did in 1900, at least not in the next few hundred years. ![]() Eradication was often attempted, but is unlikely to be successful except where the infestation is very limited and the host is well isolated from more general disease occurrence . Oregon continues to quarantine all chestnuts and chinquapins from eastern states the last report of the disease in the state was 1934 . ![]() This may account for the lower diversity of vegetative compatibility types in Europe than in America, facilitating spread of hypovirulence (see below). Although the disease is well established and widespread, Europe has maintained the quarantine . Quarantines, unfortunately, were applied after the invasion of Europe and North America. Quarantine and eradication are two management approaches that are often attempted with non-native diseases. It is also present in Europe, and the pathogen is native to China, where it causes an inconsequential disease of Chinese chestnut. In North America, chestnut blight is present in the entire native range of the host and has moved to areas of planted chestnut far from the native range. They grow rapidly and in most cases continue to develop until the stem is girdled and killed then they continue to colonize the dead tree. But it doesn’t just infect shoots it infects branches and stems of any size. Perhaps it is called blight because infected branches and stems die quickly, as in a shoot blight. SymptomsĬhestnut blight is a canker disease. Even after the branch or stem is girdled and killed, the fungus continues to colonize it, producing ever more inoculum. The fungus grows in the inner bark and cambium, producing small brownish mycelial fans. It is thought that insects of various kinds make most of the infection courts. Disease CycleĬonidia and ascospores can infect wounds, even very small ones that don’t go all the way to cambium. Environmental conditions are conducive to disease throughout the range of chestnut. Within the range of environmental conditions found in the geographic range of chestnut, there do not appear to be important differential effects of the environment. ![]() Chestnut was also prized as a landscape tree. “The farmer’s hogs were fattened on chestnuts, and, to no small degree, his children were also” . The nuts were edible, not only by wildlife but also by humans. It grew fast, and would regenerate itself by root sprouts vigorously. It made up about 50% of most eastern hardwood forests. The heartwood could be used in situations where decay was a hazard. As George Hepting has written, “Not only was baby’s crib likely made of chestnut, but chances were, so was the old man’s coffin.” One of its good qualities was high durability. It was a huge, majestic tree, with a very straight stem. If you could custom design the ideal tree species, you couldn’t come up with a better one than American chestnut. Some oak species ( Quercus spp.) get minor bark infections that can produce inoculum. mollissima) is resistant a small canker can occur. ozarkensis) are also aggressively attacked and killed . American chestnut ( Castanea dentata), whose native range is shown at left, is highly susceptible to the disease.
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