Agriculture Reference
In-Depth Information
Dried allium seedheads
Bacterial soft rot (pathogen:
Erwinia carotovora
) is a bacterial disease that can affect onions in stor-
age. Onions can be infected in the garden, especially in wet years or when the soil is generally wet, but
symptoms do not appear until they are put into storage. The disease can be recognized by the espe-
cially sulfurous odor it causes. Remove infected plants immediately. The leek moth (
Acrolepiopsis as-
sectella
) sometimes attacks onions. Thrips and stem nematodes are also known to infest onions. Pre-
vention: insect netting.
CULTIVATION HISTORY
The common onion is known only in its cultivated form, making it one of the
few crops where domestication led immediately to the establishment of a new species. The oldest evid-
ence of the cultivation of onions are illustrations from around 2665
BC
in Egypt. The oldest evidence
from the Mediterranean comes from Crete (2000-1400
BC
), which had trade relationships with Meso-
potamia and Egypt. Romans spread the onion to the north. Onions are found in central European texts
starting in the early Middle Ages. Doctor and botanist Leonhard Fuchs described red, yellow, and
white varieties in 1543. A lot of breeding work has been done on the onion in the last 50 years; com-
mercial varieties are predominantly hybrids.
SHALLOT
Allium cepa
var.
aggregatum
Shallots are more difficult to find on the market than onions; for one thing, they are much harder to
peel, leading many people to decide not to bother with them. Top chefs, however, swear by their aro-
matic qualities. They also have their advantages in the garden, as they ripen before onions. Young
leaves can be used as green onions. Shallots are smaller than onions, but they are spicier and sweeter,
yet at the same time milder. And if you reflect on how often halved onions have gone bad in your refri-
gerator, their smaller size starts to seem all the more sensible.
