Agriculture Reference
In-Depth Information
The carrot fly (
Psila rosae
) is a widespread pest in carrot culture. There are typically two genera-
tions per growing season, the first appearing after the last spring frost, which in extreme cases can kill
young carrot plants. The second generation appears in late summer and can be more dangerous for
seed growers because it affects carrots throughout the winter. Carrot flies lay eggs on the surface of the
soil, where larvae form, which then eat their way into the carrots and fill the channels they've dug with
their excrement, causing a rusty brown discoloration. Prevention: use an isolation tent and/or row cov-
er, select a windy plot to grow in, good crop rotation. Hot, dry weather inhibits the growth of young
larvae. The classic companion planting of carrots with onions appears to be of no help with carrot fly;
we highly recommend undersowing subterranean clover (
Trifolium subterraneum
), which can be ex-
tremely effective in preventing infestation, does not go to seed, and winter-kills.
Selection of the carrot variety 'St. Valery': these roots will be planted out the following year for seed production. Not pic-
tured but just as important as the shape: selecting for taste. Often only the best 1-5% of carrots of a given variety grown by
professional breeders are used for seed production. Home gardeners need not be quite so strict in their selection process.
These root types should not be propagated: leggy carrots, green-shouldered carrots, small carrots …
CULTIVATION HISTORY
The wild ancestors of the cultivated carrot were originally found spread
throughout Europe and Asia Minor. The modern carrot, traceable to two or three subspecies (one of
which is native to Europe), can be divided into an Asian type and a Western type. The Asian type was
presumably domesticated in central Asia from local wild varieties; individuals were selected for the
colors violet-red (attributable to anthocyanins, a flavonoid category) and yellow. The Western type was
domesticated in Asia Minor, is biennial, and has unbranched white, yellow, or orange roots. The typic-
al orange (from beta-carotene) carrot sold in supermarkets comes from 17th-century Dutch breeding.