Castanea mollissima

Good nuts to grow in the U.S. because of their resistance to blight. The tree grows tall and spreading. Two plants should be planted to ensure production of nuts. Space 30'-50' circle Zones 5 - 8.

Due to import restrictions we are unable to ship Chinese Chestnut to CA...

Chestnuts grow in zones 5-8 and will usually survive in sheltered spots in 4b. self-unfruitful; two or more varieties or seedlings must be planted to assure production of nuts.

The soil should be well drained, slightly acid, and humus. Although trees planted in poor soil will produce nuts, they are much inferior to the nuts of trees planted in good soil. Give each tree a space 50 feet in diameter.

Fertilize newly planted trees very lightly after they put out growth. In subsequent years, give the trees a 10-10-10 fertilizer in early spring at the rate of 2 cups per inch of trunk diameter.

Chestnut weevils are the worst insect pests. Control by spraying* in August at 2 week intervals or when harvesting drop nuts in a bucket of water. The unaffected nuts will sink, throw the floating nuts away. If nuts are left on the ground the insect population will increase causing more damage yearly.

Chestnuts are harvested when the burs in which they are enclosed open and the nuts fall to the ground. Occasionally, however, the burs fall without releasing the nuts; in which case, you must open them by hand. Pick up the nuts every day, because they deteriorate if left in the sun. They must then be cured for three to seven days-until they feel a little soft- in order to reduce their moisture content and increase their sugar content. Placing them in a shady, airy place either in trays of in open containers does this.

Store nuts in ventilated plastic bags in the fresh-food compartment of your refrigerator. Large quantities of nuts can be mixed with barely damp peat, placed in light plastic bags and stored in a garage or basement at temperature just above freezing (this storage method is preferred if chestnut weevils are known or thought to be present). They will keep for months.

A customers wrote his experiences dealing with the chestnut weevil. I got on the internet and read up on the life cycle of the lesser chestnut weevil.
The article said the weevil lays its eggs when the burrs start to open and the eggs
hatch in about 4 days. This makes sense. The solution? I pick up the eggs EVERY
DAY and put them in the fridge. The 45-degree temperature is too cold for any eggs
to hatch. I read that some people put the nuts in 140-degree water for several
minutes. It doesn't hurt the nuts, but the temperature kills the eggs. I have six
large trees, so I am very busy this time of year giving nuts to other people. I
tell them to keep the nuts in the fridge until they use them. I eat some nuts
raw. Others I "roast" in a microwave. I cut a dozen nuts in half and nuke them for
1 1/2 minutes. I like the roasted nuts hot, so I can eat a dozen nuts before they
get cold. Cutting them in half serves three purposes. Unless the shell is pierced,
the nuts will explode. Cutting them in half makes it easy to get the nut out of the
shell. Cutting the nuts in half lets me catch the occasional wormy nut. Some nuts
remain in the burrs longer than others and the lingerers have a greater chance of
having worms. Being diligent with picking the nuts up reduces the number of mama
weevils the next year. Some weevils remain in the ground for two years after
exiting the nuts. I pick up the bad looking nuts along with the good nuts just to
make sure they do not harbor worms. I throw away the bad nuts later in a trash
bag. I also am fairly diligent about picking up burrs and putting them in trash
bags just in case they have unhatched eggs on them. FYI - I use a Wal-Mart grabber
to pick up nuts and especially burrs. I have cut a dozen nuts in half, put them in
the sealable snack bags and put them in the freezer. This winter I can open one of
the frozen bags, nuke for the same 1 1/2 minutes, and have hot roasted chestnuts any
time I want. They taste as good as fresh.
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. Science 34:917.