The chestnut blight is abundantly present on the east slopes of the mountains along the French-Italian border; although it has not yet been found in France, its distribution in adjoining Italy makes it highly probable that advance spot infections are already present in France. The blight has spread into Tessin Province in southeastern Switzerland where it is destroying many of the orchards and forest trees. A large chestnut extract plant in this Province uses wood in making tannin for leather manufacturers. However, this plant, as well as some of the extract plants in northern Italy, is unable to utilize the chestnut wood as fast as the blight is killing chestnut trees.
In Yugoslavia, chestnut blight is spreading rapidly in the orchards and native growth along the Italian border. Authorities are actively cutting out all advance spot infections, to delay or possibly stop its spread across their country. In Yugoslavia, chestnut stands frequently are widely separated, a natural advantage in delaying the spread of the blight.
Chestnut blight has been controlled in western North America, where chestnut orchards and plantings are not numerous. Scattered infections have been found during the last 30 years in California, Oregon, Washington, and British Columbia; infected trees have been removed. Strict State Quarantine regulations have been enforced, to prevent chestnut blight from spreading to the West Coast.
The chestnut blight fungus is attacking three of the important oaks of Europe. The typical fanlike mycelial growth can be observed in the bark of infected oaks. In 1953 in Yugoslavia I observed vigorous young durmast oak (Quercus petraea) being killed by the blight. In Italy I found the disease killing pubescent oaks (Q. pubescens) and causing minor injury to the holly oak (Q. ilex). Before we can estimate the probable damage to these European oaks, we need more information on the effects of this disease on oaks of various ages and under various environmental conditions. In the United States the post oak (Quercus stellata) is the only oak species that has been seriously damaged by the blight.
Thus, the blight is threatening not only the native chestnut forest growth and orchards of Europe, but also the oaks. A steady extension of the blight throughout Italy can be expected. Advance infections in Yugoslavia are being cut out but how long the disease can be held back depends on future efforts along this line. Delay work in Yugoslavia also delays the time of loss of the chestnut and damage to the oak growth of Greece and Turkey. The inspection and eradication work being carried out in Spain may result in the elimination of this threat to the chestnuts and oaks in Spain, Portugal and southwest France. However, there is the possibility of the blight occurring anywhere in Europe. People working with chestnut should be on the alert to find and eradicate the first infections.
The film entitled "It Bringeth Forth Much Fruit", shown here today, was prepared at my suggestion by the U. S. Foreign Agricultural Services at Rome. It is being used to aid local authorities in Italy in attempts to delay the spread of the chestnut blight.
The Italian authorities, with assistance from the United States Foreign Agricultural Service, have purchased blight-resistant chestnuts in this country for planting in Italy. These resistant chestnuts are doing very well in Italy so far. However, the development of a new orchard industry with the Chinese chestnut and its hybrids in Italy will be a slow process. It is expected that shipments of chestnuts from Italy to this country, which is now going on at a rate of 15 to 18 million pounds per year, will gradually decrease.
DR. GRAVATT: I will talk on while they are fixing this next film.
Much of the trouble in Italy is that so many of the chestnut orchards are overgrazed, sadly overgrazed, and as these chestnut orchards are killed by the blight, the land is going back into this overgrazed condition, which leads to serious erosions. Italy needs all the water that can be saved. The mountains are eroded down to the rock in many areas and when you get to the rock, you can never bring the soil back. It's a serious problem to meet because of the tremendous over-population. Every little twig of wood is used. As these chestnut orchards are killed it's going to be a very difficult problem to plant them again because the land is overgrazed. Protecting the plantings against sheep and the goats is quite a problem.
(The film, "The Filbert Valleys," was shown.)