Agriculture Reference
In-Depth Information
The most important fungal disease, especially for zucchini, is powdery mildew, caused by the
fungus Erysiphe cichoracearum . It appears first as powdery spots on leaf tops, spreading then to be-
come a whitish gray layer on the tops and bottoms of leaves, then ultimately covering stems and fruits.
Powdery mildew mainly affects older plants in cool weather in late summer, when dew forms
overnight and plants do not dry well in the cool days. If such a cool period is then followed by a return
of sunny, warm weather, the fungus thrives and spreads. Serious cases can interfere with seed ripening.
Powdery mildew is not seed-borne but can be spread by infected plant material in compost or mulch.
The fungus Rhizopus stolonifer can cause rhizopus soft rot in stored fruits.
CULTIVATION HISTORY All Cucurbita species originated in the New World. The fruits of most wild
squash species, bitter and inedible, were originally gathered for their nutrient-rich seeds and durable
rinds. Squash is still grown along with corn (maize) and beans in the milpa crop-growing system of
Mesoamerica.
Cucurbita pepo comes from the Mexican squash C. fraterna and the Texan squash C. pepo ssp. mi-
crocarpina var. texana , both of which wild forms have bitter fruits and stringy flesh. Presumably, they
were first grown for their highly nutritious (though small, compared to present-day pepe squash)
seeds; earliest evidence of domestication is between 7500 and 5500 BC in northeastern Mexico. Cucur-
bita maxima derives from the South American species C. andreana ; the original form of maxima
squash is found in Argentina and Bolivia. First evidence of cultivation comes from coastal areas of
Peru between 2500 and 1500 BC ; dissemination to the north began in the post-Columbian era.
Moschata squash has no known wild ancestors; it is presumed to have been domesticated around 5000
BC in southern Mexico and Central America. Nor has the wild ancestor of C. ficifolia been traced,
though we do know it was first cultivated in the mountainous regions of Peru (oldest evidence is circa
3000 BC ). Cucurbita argyrosperma is from Mexico and Guatemala.
PEPO SQUASH
Cucurbita pepo
The name “pepo squash” is not commonly encountered outside of seed-saving circles, but we have no
hesitation in using it here, for our audience, to avoid confusion. Plants have rough, prickly leaves,
ribbed shoots, and hard stems with prickly hairs and five to nine ribs. Leaves are often distinctly five-
lobed, sometimes cut away deeply, and mottled. Zucchini and scallop squash are classic summer
squashes. Though some forms like pumpkins, acorn squashes, and varieties like 'Sweet Dumpling' and
'Delicata' are eaten ripe, practically all other pepo squashes are eaten unripe. Pepo squash flesh is
more (spaghetti squash) or less “noodle-y” and maintains its integrity even when cooked. When grow-
ing summer squash for seed, do not harvest when normally harvested for eating, as the seeds have not
yet ripened. Fruits should remain on the plant until the skin can no longer be scratched with a finger-
nail and the stems begin to dry. At this point they can be removed from the plant and set in a cool
place to finish ripening. Fruits must then be broken into to remove the seeds. This is made easier for
zucchini after a light frost, which makes seeds easier to separate from flesh. If you live in an area
where seed ripening coincides with the first autumn frost, simply leave fruits in the garden until the
first autumn frost. The seeds themselves should not be allowed to freeze. Do not use this method if, for
example, seeds are ripe in late summer and the first frost is not expected until late autumn, as the seeds
Search WWH ::




Custom Search