HORT410 - Vegetable Crops
Watermelon - Notes
Common name: watermelon.
Latin name: Citrullus lanatus (Thunberg) Matsumara & Nakai (also called C. vulgaris).
Family name: Cucurbitaceae [Cucurbitaceae Images].
Diploid (2n = 22) [but note that some cultivars are tetraploid, and seedless watermelons are triploid].
Pollinated by bees.
Harvested organ: large fruits.
Fruits have a hard rind and a soft, sweet-fleshed interior when ripe.
Origin: native to Africa; introduced into N. America during the 16th century.
Watermelon history (TAMU).
Warm season, frost suceptible.
Number of fruits per vine varies from 2 to 15.
Weight of each watermelon ranges from 3 lb to 50 lb.
Flesh color variable: red, pink, yellow, or white.
Monoecious and andromonoecious types of flowering habits; monoecious most common.
F1 hybrid watermelons becoming increasingly popular; the production scheme is similar to maize [plants of the maternal and paternal parents are grown in alternate rows; male flowers in maternal rows are removed by hand in the early morning when insects are not present; female flowers in these rows receive only pollen from the paternal parent].
Most cultivars are diploid, but triploids and tetraploids are becoming increasingly important.
Triploid watermelons produced from the cross of tetraploid and diploid forms; the triploid hybrids are almost seedless.
Watermelons reach maturity approximately 45 days after blooming; highly dependent upon cultivar.
Typically harvested when the tendril nearest the melon is wilting and the ground spot has turned from white to yellow.
Immature watermelons have turgid tendrils; a completely wilted tendril can be indicative of over-maturity.
Fruit is rich in sugar (soluble solids); a sugar content of 17% is considered excellent quality.
Other indicators of ripe fruit include ridges on the rind surface, and a hollow or dull sound when "thumped".
Fruit should be cut cleanly from the vine to avoid stem damage and prevent stem-end rot.
Fruit is chilling sensitive and should not be stored below 7 C; optimum storage temperatures are 7 to 10 C.
Major diseases of watermelons in the Midwest:
Major insect pests of watermelons in the Midwest:
Cucumber beetles are of lesser concern to watermelon growers than cucumber and muskmelon growers because watermelon is not
susceptible to bacterial wilt.
Protection of watermelons from cucumber beetles is necessary when plants are small and high beetle populations are feeding on stems, or when beetles are feeding on the fruit.
Careful when applying pesticides that are toxic to honey bees during flowering; can decrease pollination and fruit set.
(see: ID-56: Midwest Vegetable Production Guide for Commercial Growers 2003 - Cucumber, Muskmelon, and Watermelon (PURDUE) [pdf] for watermelon crop recommendations (varieties, spacing, fertilizing, irrigation, harvesting, disease, weed and insect control) for the Midwest)
Sources of information:
Foster, R., Brust, G., Barrett, B. Watermelons, muskmelons, and cucumbers. In "Vegetable Insect Management With Emphasis on the Midwest", (ed. R. Foster, B. Flood), Meister Publishing Co., Willoughby, Ohio, pp. 157 - 168 (1995).
Nonnecke, I.L. "Vegetable Production", Van Nostrand Reinhold, NY (1989).
Phillips, R., Rix, M. "The Random House Book of Vegetables", Random House, NY (1993).
Hall, C.V. Watermelon. In "The Software Toolworks Multimedia Encyclopedia", Version 1.5, Grolier, Inc. (1992).
Feher, T. Watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai. In "Genetic Improvement of Vegetable Crops", (ed. G. Kalloo, B.O. Bergh), Pergamon Press, Oxford, U.K., pp. 295-311 (1993).
Midwest Vegetable Production Guide for Commercial Growers, ID-56, eds. R. Foster, D. Egel, E. Maynard, R. Weinzierl, H. Taber, L.W. Jett, B. Hutchinson, Purdue University Cooperative Extension Service, 2003.
Musmade, A.M., Desai, U.T. Cucumber and melon. In "Handbook of Vegetable Science and Technology: Production, Composition, Storage, and Processing", (ed. D.K. Salunkhe, S.S. Kadam), Marcel Dekker, Inc., NY, pp. 245-272 (1998).