The International Chestnut Commission and the Chestnut Blight Problem in
Europe, 1953
G. FLIPPO GRAVATT, Senior Pathologist, U. S. Plant Industry Station,
Beltsville, Maryland
The International Chestnut Commission was organized under the auspices of the Food and Agriculture Organization of the United Nations. The aim of the Commission is to promote international cooperation in the study of all scientific, technical, and economic questions relating to chestnut growing. The main problem facing all chestnut culture in Europe is the rapid spread of the chestnut blight. France, Italy, Japan, Portugal, Spain, Switzerland, Turkey, United States and Yugoslavia are members of the organization. A representative from the F.A.O. in Rome serves as Secretary of the Commission. An international conference on chestnut problems was held in France in 1950, the first meeting of the Commission was held in Italy and Switzerland in 1951 and the second in Spain and Portugal, June 18-30, 1953. The average attendance at the meetings was 50 to 60 persons. I have attended all three conferences as the representative from the U.S. Departments of State and Agriculture.
The International Chestnut Commission meetings differ from the meetings of the Northern Nut Growers Association in many ways. Our Northern Nut Growers Association meets annually for 2-1/2 days while the meetings of the International Chestnut Commission last from 10 to 12 days but not every year. In Europe the members travel mostly in a large tourist bus, which carries the party for hundreds of miles, visiting nurseries, orchards, chestnut utilization plants and not neglecting the scenic parts of the route. All lodging and meals are carefully arranged for in advance. The group in Europe is made up quite largely of Federal and State professional workers, University professors, and representatives from the chestnut utilization industries.
Among the places which the delegates visited in Spain in 1953 was the Agricultural Experiment Station at La Coruna, where the Phytophthora ink disease of the chestnut has been studied extensively. They also visited the Experiment Station at Pontevedra, where new methods of propagating chestnuts are being studied. At Bilboa and at Villa Presente Nursery, Santander, we inspected plantings of Asiatic chestnuts; I found chestnut blight present on several trees at both locations and recommended immediate removal of the diseased trees. Fortunately, the Asiatic chestnuts are some distance from any native European chestnuts at each place and, according to the local foresters, the blight has not spread to the distant stands of native chestnut. Some years ago the Spanish authorities imported seed from Asia; chestnut blight probably was brought in on these nuts. All infected trees that are found are being destroyed, but a thorough inspection and eradication program is needed to control the disease before it spreads into the native European chestnut stands, from which the disease probably would spread into Portugal and southwestern France.
In Portugal we inspected many very fine chestnut orchards. These orchards are composed of grafted varieties, with only 3 or 4 varieties in each locality or region. Because of this there is a more standard nut product in most of Portugal than in the other European countries where mixtures of local varieties are frequently grown. A very large portion of the European chestnut orchards in Portugal are made up of seedling trees, topworked with local selections. In Portugal most of the orchards are located on the lower slopes and various crops are grown among the trees. In most other European countries the orchards are on rougher mountain land which is grazed.
In Portugal the State Road Department has established a number of roadside plantings of chestnut. These plantings are very productive. The State Road Department sells the nut crop to the highest bidder and uses the funds for additional roadside tree plantings.
In northern Portugal authorities have conducted a large-scale program to control the Phytophthora ink disease of chestnut by the following treatment: The soil is removed from the base of the tree and larger roots. The base and roots are sprayed with a sticker compound and then dusted with copper oxide and copper sulfate before the soil is replaced. Treatment is repeated every 5 to 7 years. Government officials secured the cooperation of owners of chestnut stands in treating practically all trees over large areas. Although this treatment for the Phytophthora ink disease was originally worked out by the Spanish pathologists at La Coruna, it has not been used extensively in Spain. The Phytophthora root disease is damaging chestnut orchards throughout southern Europe. In 1950 I noted that this disease was causing severe damage even in Asia Minor. In the southern part of the United States this same disease (here called Phytophthora root rot) caused heavy losses at lower elevations.
The 1953 Chestnut Commission meeting terminated on June 30 at the famous Palace Hotel at Bussaco, Portugal, where the Under Secretary of Agriculture gave the delegates an official farewell dinner. No definite plans were made for the next meeting of the Commission. It was the general opinion that a meeting in the United States would be poorly attended because of the expense of sending the delegates from Europe.
After the conclusion of the meeting, the U. S. Foreign Agriculture Services sponsored my trip to France, Italy, Switzerland, and Yugoslavia, to consult with Federal and local authorities on their chestnut blight problems. This disease was found in Genoa, Italy, in 1938; later it was determined that the disease was present at that time in other localities in Italy. The blight is spreading rapidly and is almost completely destroying the orchard and larger forest trees of European chestnut in Italy in localities where the disease has been present for some time. The blight occurs in many areas in northern Italy and as far south as Naples. The young chestnut coppice is not so seriously affected, but the losses caused by the blight will make growing coppice on a 10- to 20-year rotation basis less profitable than formerly.