Page 210 - Encyclopedia Of World History

560 berkshire encyclopedia of world history

Scientists came quickly to understand that control of famine in the early fourteenth century may explain the
insect populations is essential if one hopes to minimize high mortality of the Black Death. Plague, if the cause of
crop damage from an insect-borne pathogen. It was no the Black Death, should not have killed between a third
longer enough for the plant pathologist to understand and half of Europe’s people between 1347 and 1351, for
diseases. He now had to understand the feeding and plague is a disease of rodents and other small mammals.
mating habits of insects and their distribution in areas of Yet ergotism and famine may have left Europe’s peasants
disease. The need to combat insects accelerated the and urban poor too weak to ward off plague.The result
study and development of insecticides as a branch of was the worst pandemic of the Middle Ages.
applied chemistry in the twentieth century.The study of
insect-borne viruses and the development and use of Diseases of the Staple Crops
insecticides would later be crucial in fighting corn dis- Indigenous to the Americas
eases in the United States. Late Blight of Potato
The fungus that causes late blight of potato is at the cen-
Rye Ergotism ter of a tragedy, the Irish Potato Famine.The tragedy has
The importance of wheat and rice to the sustenance of its roots not in Europe but in the Andes Mountains,
Europeans and Asians has deflected attention from rye where the natives of Peru domesticated the potato. The
and its diseases. The Germanic tribes that settled the Spanish conquered Peru in the sixteenth century. In
lands that are today France and Germany began growing search of gold, they found a more valuable commodity,
rye in the second century CE.Wheat always commanded the potato. From Peru the potato reached Spain by ship
a higher price than rye, making rye bread the staple of the around 1570, then spread west through continental
poor until the even cheaper potato spread through Europe and north across the English Channel, reaching
Europe between the sixteenth and nineteenth centuries. Ireland before 1800. On the continent, the potato vied
The diseases of rye thus afflicted the poor rather than with rye bread as the staple of the poor. In Ireland poli-
the rich. Particularly serious was ergotism, a fungal dis- tics and economic exploitation made it the only staple.
ease that fills rye grains with a toxin that in sufficient For many years the Irish sought independence from
quantities causes convulsions and death in humans. England, a goal England’s Lord Protector Oliver Crom-
Unlike most plant diseases, ergot of rye threatens humans well crushed. In the 1650s his army ravaged Ireland and
by poisoning them rather than by causing famine. The Cromwell divided the land among his supporters.These
agony of death from ergot toxicity led medieval Euro- men charged rents so high that the Irish peasant could set
peans to attribute the disease to God’s wrath, hence the aside only a small plot of land for his family.The rest of
name “Holy Fire.” Medieval chronicles cite the first out- the land went to raise the grain and livestock peasants
break of Holy Fire in the eighth century. In 857 CE, thou- needed to pay rent.
sands died in the Rhine Valley, with smaller outbreaks By 1800 the Irish, squeezed by their lack of land and
throughout France and Germany. high rent, had no choice but to embrace the potato for
One may recall that fungi spread in wet environments. sustenance because it yielded more food per unit of land
Evidence from dendrology and medieval chronicles sug- than any grain. Reliance on a single crop is always risky,
gests that after 1000 CE, Europe’s climate turned wet and as Columella had emphasized in the first century. The
cool, hastening the spread and severity of ergotism in potato posed risks far greater than the Irish could have
northern and western Europe. An outbreak in 1039 was imagined.The Spanish had brought little more than a few
the first in a series of virulent outbreaks between the handfuls of potatoes with them. These potatoes were of
eleventh and eighteenth centuries. Ergotism along with the same stock and thus genetically uniform. Because the