FACT SHEET 1-Water Melon growing.pdf - Nabuur

watermelons are ripe. A combination of the following indicators could be used to determine if the
watermelon is ripe for harvesting:
• Light green, curly tendrils on the stem near the point of attachment of the melon usually turn brown
and dry;
• The surface color of the fruit turns dull;
• The skin becomes resistant to penetration by the thumbnail and is rough to the touch; and
• The bottom of the melon (where it lies on the soil) turns from light green to a yellowish color, i.e. as
watermelon ripens, the ground spot changes from pale green or white to cream or yellow.
The ripeness of a watermelon can also be determined by "thumping" the melon with a knuckle. The sound
of a watermelon, when thumped with a finger, is a muffled, dull tone if it is ripe. An immature fruit will
thump with a clear, metallic ringing tone. Many watermelons do not emit the proverbial "dull thud" when
ripe. For these, the dull thud may indicate an over-ripe, mushy melon
Watermelons often weigh between three and 25kgs upon maturity.
Insects and Diseases
Watermelons are susceptible to various pests and diseases that attack the roots, foliage, and fruit resulting
in reduced yields. These include: Fusarium wilt, anthracnose, damping off, gummy stem blight, bacterial
fruit blotch, yellow vine, bacterial rind necrosis, cercospora leaf spot, angular leaf spot, alternaria leaf
spot, Phytophthora blight, powdery mildew, downey mildew and viral diseases. Some cultivars are
resistant to some diseases.
Powdery mildew is one of the severest watermelon diseases. It is caused by 2 fungal pathogens, Erysiphe
cichoracearum and Sphaerotheca fulginea. These fungi occur mainly on leaves, which are most
susceptible 2 to 3 weeks after unfolding. Powdery mildew appears as a dusty white or gray coating/
fungal growth over both upper and lower leaf surfaces or other plant parts, and can be difficult to control.
Exposed vines and fruit are more prone to sunscald, and the vines may shrivel. Powdery mildew also
affects cucumber, squash, pumpkin and other varieties of the family Cucurbitaceae.
Disease control is essential in order to have high-yields and high quality watermelons. For disease
management:
• Select a site with good air circulation and low humidity
• Separate new plantings from old plantings
• Use a crop rotation of at least one year
• Control cucurbit weeds and other weeds.
The most common pests are cucumber beetles. If they attack watermelon plants, apply a suggested
insecticide for control. Watermelon mosaic virus (WMV) and yellow mosaic virus (ZYMV) are other
pests that infect cucurbits: melons, cucumbers, luffas, squash and pumpkins, and are usually transmitted
by insects.
Nutrition
A traditional food plant in Africa, watermelon has potential to improve nutrition and boost food security.
Watermelon contains about six percent sugar by weight, the rest being mostly water (it is 92% water by
weight). As with many other fruits, it is a source of vitamin C but is not a significant source of other
vitamins and minerals unless one eats several kilograms per day. Watermelons also contain a significant
amount of amino acid citrulline.
4
www.slint.org
“Empowering people to secure sustainable incomes, food security and improved quality of life in harmony with nature”