Vegetable Vampires

Deadly rivals of man and beast for the life-sustaining juices of the earth's green plants are a vigorous group of non-green plants--the fungi. For ages men watched helplessly while these vegetable vampires literally sucked the green blood of plants, wasted their crops. But about 100 years ago, men armed themselves with scientific weapons and began a desperate war--still raging--against the fungal underworld. Last fortnight, in The Advance of the Fungi (Holt; $4), British Chemist E. C. Large offered a vivid story of the last century's battles, a brilliant reconnaissance of the enemy's present positions.

Fungi (with the algae which do have chlorophyll) are the earth's oldest and most primitive plants, lacking root, stems and leaves. Fungi also lack the power of green plants to make food out of sunlight, carbon dioxide and water, and must therefore live off organic matter. So there are two types of fungi: 1) parasites, which feed on living plants and animals; 2) saprophytes, which feed on dead organisms. Pleasant are some fungi, such as the mushrooms (commercially grown on horse manure) which decorate steaks. Valuable are others, like the bacteria which decompose dead organisms, fix nitrogen in the soil, promote fermentation.* Harmful to man are fungi which attack crops.

The potato came to Europe from the New World in the 16th Century. Its parasitic fungus followed about 1840, attacked almost every potato plant in Europe. Worst outbreak was in Ireland, whose wretched peasantry was already starving because of another parasite, the English landlord. Between 1845 and 1860, in the greatest disaster since the Napoleonic Wars, 1,000,000 Irish died directly because of potato fungus, and 1,500,000 emigrated. English industrialists used the Irish famine as a pretext to repeal the Corn Laws (which limited food imports). This, says Chemist Large, was "perhaps the most significant single event in the history of the British Empire." Reason: it inaugurated Free Trade and the Empire's Golden Age. Groused the Duke of Wellington: "Rotten potatoes have done it all."

Few botanists then believed that the potato blight was caused by fungi, which were thought to grow only on dead things, never on living plants. But when the fungus was at last proved guilty, botanists opened their eyes wide. They found fungi to be:

> Cryptogamic--i.e., devious in sexual behavior. As late as 1875 many scientists argued that some fungi were of spontaneous generation. So tiny and evasive were the winter spores of the potato fungus that they were not identified until 1910. Further, reproduction among fungi was usually sexless, with a sexual union occurring perhaps only once in several generations.

> Polymorphous--i.e., varying radically in form from season to season (like insects which are now egg, now worm, now butterfly). Plants once classed as unrelated proved to be variant forms of one species. And as a fungus changed form, it often changed the host it preyed upon.

With this baffling enemy sized up, intelligent defense could begin. The rust, a fungus which destroyed 300,000,000 bushels of wheat in North America in 1916, was proved to pass part of its life cycle on barberry bushes. So, within twelve years, some 18,500,000 of these bushes were destroyed in the U. S. alone. Wild currants were eradicated because they nourished a blister-fungus of U. S. white pine.

A main line of attack was with chemicals. Problem: to find fungicides that would not hurt the crops. During the past decade the Boyce Thompson Institute for Plant Research (Yonkers, N. Y.) has experimented with almost all the standard elements, but farmers still rely chiefly on compounds of sulphur, mercury and copper. Since 1921 crops have been dusted with poison from airplanes. This is the most perilous branch of commercial aviation.

Another line of attack against plant fungi is to develop naturally immune strains by breeding. At the turn of the century long-fibred U. S. cotton was rescued from fungus by crossbreeding with a resistant Egyptian variety; in the 1920s Louisiana sugar cane was saved by supplanting the old "noble" strains with resistant breeds. In 1937 the U. S. Bureau of Plant Industry estimated that more than one-fourth of U. S. farmlands were planted to disease-resistant crops.

*Fortnight ago a fungus was insured by Lloyds of London for $1,000,000. Policyholder is the Falstaff Brewing Corp. of St. Louis, which thus treasures its unique, 50-year-old brewer's yeast.

This file is automatically generated by a robot program, so reader's discretion is required.