Agriculture Reference
In-Depth Information
following tomatoes or near tomatoes in the same year; apply stinging nettle and horsetail slurry. Treat-
ment: remove and destroy (burn or hot compost) afflicted foliage (tubers can be eaten). Tubers from
infected plants can be used as seed potatoes only when the foliage was removed early enough; other-
wise, the tubers themselves are also infected, and the disease will likely spread in storage and in the
following crop. Early potato varieties are at lower risk of potato blight than late varieties.
Various viruses pose an additional threat and cause a reduction in yield from year to year. Symptoms
vary. A mild infection may go undetected. In more serious cases, leaves may turn yellow and curl up
and/or be stunted. Tubers do not grow to be very large. We recommend pulling the greens of plants
that appear to have a virus; do not further propagate such plants. Prevention: find a so-called field-res-
istant variety that yields well despite infection. Such varieties can be hard to find. If you come across a
variety that is grown year after year in a garden or field and yields never go down and plants never ap-
pear sick, this is likely a field-resistant variety.
The Colorado potato beetle (
Leptinotarsa decemlineata
) can cause significant crop damage in some
years. The beetle crawls out of its winter quarters around the time dandelions start to bloom. It feeds
on the foliage of potato plants and leaves eggs behind on leaf undersides. Two weeks later, red larvae
with black spots on their sides emerge. In severe cases, the beetles can defoliate an entire crop. Treat-
ment: early and regular collection and removal of beetles, eggs, and larvae. In rare cases, apply a Bt
(
Bacillus thuringiensis
) solution. This should truly be the exception and not the rule, as regular use of
this organic pesticide can quickly lead to a buildup of resistance in the potato beetle. Another unwel-
come pest is the wireworm (the larvae of various beetles of the family Elateridae). They often appear
after grasslands are plowed and gnaw on roots, thereby killing plants, and chew holes and tunnels into
tubers. Prevention: not using fresh manure in amending soil, encouraging natural enemies like hedge-
hogs and birds. Treatment: cut potatoes into slices and bury as a decoy; dig up after a few days, and
collect and destroy wireworms. Slugs may also appear after plowing up grasslands and cause even lar-
ger holes in tubers than wireworms. Nematodes (
Globodera rostochiensis
and
G. pallida
), or round-
worms, also affect potatoes. Pinpoint-sized cysts are found on roots in early to mid summer; these con-
tain roundworm eggs. Symptoms: stunted growth, wilted leaves. Prevention: not growing any crops in
this garden for three to four years, especially nightshades, chenopods, and sorrel.
CULTIVATION HISTORY
Eight thousand years ago, the potato was already an important crop plant for
the indigenous peoples of South America, and in the Peruvian and Bolivian Andes, it remains, along
with corn (maize) and beans, a staple food to this day. Potatoes thrive at altitudes that are too cool for
corn. Andean farmers plant many potato varieties together, but certain dishes are each prepared with
only one variety.
The potato appears to have been brought independently and separately to Ireland, England, and
Spain. It took around 200 years for it to really take off in the Old World. The first Europeans to have
potatoes were royal families and their gardeners: Clusius, the gardener at the Imperial Botanical Gar-
dens in Vienna, provided the first botanical description of the “Papas Peruvianum”; the first European
to grow potatoes on a field scale was the Prussian Great Elector Friedrich Wilhelm in 1651.
