(Castanea pumila) also spelled "Chinkapins" and sometimes called dwarf or bush chestnuts are shrubs and small trees commonly found through the eastern, southern, and south-eastern United States. The plants usually bear one nut per bur and have burs (involucres) that open into two halves, such as a clam shell.
The Allegheny chinquapin, also called the American, common, or tree chinquapin, may well be our most mistreated and misrepresented native North American nut tree. It has been widely hailed as a sweet and edible nut; wood source for fuel, charcoal, fence post, and railroad ties; coffee and chocolate substitutes; for wildlife (birds an mammals); dwarfing rootstock for other Castanea spp.; and a blight-resistant taxon for hybridizing with other chestnut species; in addition, the root has been used as an astringent, a tonic, and to treat fevers.
Castanea pumila var. pumila is a large, spreading, smooth-barked, multi-stemmed shrub that is 2 to 4 m tall. Occasionally, there is but a single stem and the plant may reach 5 to 8 m. Large trees are sometimes found especially where humans have intervened and removed competing trees.
The Allegheny chinquapin is found in dry sandy woods and thickets from southern New Jersey and Pennsylvania, west to Indiana and Missouri , and south to Florida and Texas. It is usually ready for harvest in early September. Harvest must be prompt to gather nuts before wildlife (birds and small mammals) remove the entire crop.
Chinquapins are quite susceptible to Phytophthora cinnamont root rot so it is best to grow in well drained soil.
From present indications this tree will be well worthy of cultivation as an ornamental shade tree or bush. Even if we leave out of the account its rapid growth, productiveness, and delicious little nuts, which will be very acceptable for home use, if not possessing any great commercial value.
Australian Nutgrower 20:36-38 (2006)
A History of Phytophthora cinnamomi in the United States
Sandra L. Anagnostakis
The Connecticut Agricultural Experiment Station, New Haven, CT 06504
Sandra.Anagnostakis@ct.gov
Whenever a new imported pest or pathogen starts to cause problems, it is useful to remember that this is not the first time this has happened. Chestnut trees were here when the first European settlers arrived, and were generally taken for granted. When they started dying in the southern United States many reasons were presented, from drought to insect predation. The money was in the North, so little was done to find out what the problem was. Human beings have been moving pests and pathogens around the world as long as they have been traveling, and the identification of Phytophthoras as serious pathogens has happened fairly recently. The Connecticut Agricultural Experiment Station has an extraordinary collection of unpublished papers, letters, and photographs that give us accounts of early work on chestnut, and these, with later published papers, give us an account of the disaster of Ink Disease. This disease is still important because several groups are planning to introduce hybrid chestnut trees into the forests of eastern North America.
We now know that Phytophthora cinnamomi causes Ink Disease in chestnut, and that it is an imported pathogen that probably came into the southern United States before 1824. It is very interesting that this pathogen shares two disparate hosts (Castanea and Eucalyptus) with another notorious pathogen, the fungus responsible for Chestnut Blight Disease.
Ink disease was reported on chestnuts, walnuts and cork oaks in Portugal in 1838, and in 1904 Prunet said that: "The Black Foot Disease of Chestnuts.[is].of all the diseases the most to be feared." When did we recognize it, and how did it get to the United States?
When Chestnut Blight Disease started killing the chestnuts in the northern and coastal United States, people paid attention. Money was appropriated and surveys were undertaken to track the presence of the pathogen. The darkened area on the map (figure 1) is the native range of American chestnut (Castanea dentata) in the United States. In 1911, Caroline Rumbold quoted an 1856 paper by Hilgard, who had said that chestnuts in NE Mississippi were dead and dying. In 1912, George P. Clinton, from The Connecticut Agricultural Experiment Station said: "It is well known that in times past the chestnut trees in this country have suffered severely in certain districts, particularly in the south, in some cases being practically exterminated, so that their range is now considerably lessened from what it was originally. Strangely enough, no one has surely accounted for any of these devastations."
Clinton was convinced that Chestnut Blight Disease was not caused by an imported pathogen, but was a secondary infection that came in because the trees were weakened by drought and general environmental causes. Clinton said that blight had either always been here, or had been here for a long time without exterminating chestnuts, and he started collecting references to previous reports of problems with chestnuts. His files include a quote from Asa Gray (1859) that the chestnuts were dying all over the mountains in the Southern U.S. In 1912, Hopkins reported on his surveys in the south, and quoted Mr. Jones of Riceboro, Georgia: "in 1823 a great fall of rain occurred and late 1824 was also very rainy, in 1825 many chinquapin trees died and continue to do so up to 1845, if the disease is not stopped, trees will be exterminated" [chinquapins are another native species of Castanea in the United States]. This was followed by a press release in 1912 from the Secretary of Agriculture which says "In some sections of the South where more than fifty years ago the chestnut trees were abundant, very few are present today ... in the Appalachians there is a widespread death of both chestnut and chinquapin." P. L. Buttrick (1913) was concerned that for many years the chestnut trees throughout portions of North Carolina had been dying. He thought that some of the problem was due to recurring fires (figure 2) throughout the area and to heavy logging throughout state (figure 3) but found no other clear cause.
By 1932, people realized that a disease organism was responsible for this decline of chestnuts and chinquapins and Margaret Milburn and Flippo Gravatt reported a Phytophthora root disease on chestnuts that resembled Ink Disease caused by P. cambivora in Europe. They found that this was a serious pathogen on Allegheny chinquapin (C. pumila), and American and European chestnut (C. sativa), but was not serious on Japanese (C. crenata) or Chinese (C. mollissima) chestnut, dwarf Chinese chestnut (C. seguinii), or Chinese chinquapin (C. henryi).
Bowen S. Crandall (1936) first described a Phytophthora root and collar rot of pine in Pennsylvania, and in 1938 he reported finding this pathogen on pines in Maryland, on pines and several hardwoods in Virginia, and in Tennessee, Arkansas, Oklahoma, Louisiana, Georgia, and South Carolina on chestnuts and chinquapins (figure 4). Crandall then teamed up with the two previous Ink Disease researchers and in 1945 they published evidence that the pathogen was actually P. cinnamomi, and not P. cambivora (figure 5). They mapped the distribution of the pathogen over a wide area (figure 6). In 1950, Crandall noted that cork oak trees from Portugal had been extensively introduced into the United States to exactly the areas where P. cinnamomi became established: the southern U.S. and California.
In 2001, I gave American chestnuts to Dr. S. Brosi at the University of Kentucky for a large planting in the woods. In her thesis she said: "Infection by the introduced pathogen Phytophthora cinnamomi caused high mid-season mortality at three of the four planting sites Mortality ranged from 22-74% across the sites." This is a graphic illustration of the problem that is still very much with us. Even though the pathogen does not usually survive the winters north of southern Pennsylvania and New Jersey, we must clearly be concerned about resistance to Ink Disease in any trees that we plant in the eastern forests.
The Connecticut Agricultural Experiment Station, the American Chestnut Cooperators, and the American Chestnut Foundation have chestnut breeding projects and are planning to introduce timber chestnut trees into the forests of the eastern U.S. Selection for progeny with good resistance to Chestnut Blight Disease is progressing rapidly. Dr. J. Frampton and M. Bowles at North Carolina State University have tested chestnut progeny for resistance to Ink Disease. If they are successful in their efforts to understand the inheritance of the resistance to Phytophthora found in many Asian chestnuts, we will be able to integrate their information with that of other breeding programs. Understanding the history of Ink Disease of chestnuts and chinquapins in the United States can help us plan better for the future.
References
1. Buttrick, P. L. 1913. The recession of the chestnut from certain sections of North Carolina. 57pp + 9 pages with illustrations, unpublished report from the Office of Forest Pathology, U.S. Bureau of Plant Industry.
2. Clinton, G. P. 1912. Previous chestnut troubles p407-413 IN: Report of the Station Botanist, 1911, 1912. part 5 of the Annual Report of 1912 of The Connecticut Agricultural Experiment Station, New Haven.
3. Crandall, B. S. 1936. Root disease of some conifers and hardwoods caused by Phytophthora cambivora (P. cinnamomi). Plant Disease Reporter 20:202-204.
4. Crandall, B. S. 1950. The distribution and significance of the chestnut root rot Phytophthoras, P. cinnamomi and P. cambivora. Plant Disease Reporter 34:194-196.
5. Crandall, B. S. and Hartley, C. 1938. Phytophthora cactorum associated with seedling diseases in forest nurseries. Phytopathology 28:358-360.
6. Crandall, G. S., Gravatt, G. F., and Ryan, M. M. 1945. Root disease of Castanea species and some coniferous and broadleaf nursery stocks, caused by Phytophthora cinnamomi. Phytopathology 35:162-180.
7. Gray, A. 1859. Memoirs of the New York Academy volume 6 part 1
8. Hopkins, A. D. 1912. The relation of insects to the chestnut blight disease. 6pp. Bureau of Entomology, U.S. Department of Agriculture, unpublished report.
9. Milburn, M. and Gravatt, G. F. 1932. Preliminary note on a Phytophthora root disease of chestnut. Phytopathology 22:977-978.
10. Prunet, A. 1904. Le reconstitution des Chataigneries. Bul. Mensuel de L'Office de Reseignements Agricoles 3:536-541.
11. Rumbold, C. 1911. A new record of a chestnut tree disease in Mississippi.