Water melon ( Citrullus lanctus) is a common fruit in Kenya grown for its nutritive and market value.
Varieties grown in Kenya include
Watermelon is a warm season fruit, it therefore requires a lot of sun and good drainage to develop optimally.
Watermelon thrives best in temperature ranges of 17°C – 20°C
Soil pH for watermelon should range between 6.0- 7.0.Soils that are highly acidic do not favour watermelon growth; this can be corrected by use of basic fertilizers such as gypsum or lime. The soils should also be well- drained and rich in organic matter.
Recommended spacing for watermelon growing is 90-120 cm between seeds and a range of 150 – 180 cm between rows.
Given that watermelon has a deep root system crop rotation should be done with crops that have a shallow root system such as maize.
Watermelon is sown directly into the soil, however, transplanting can also be considered.
In hot regions such as Embu, Machakos and other Eastern regions water melons are bigger and sweeter. An acre of land under good irrigation and management could yied 20- 25t which translates to ksh 500,000 given that a kg goes for ksh15-20.
A watermelon nutritive value cannot be overlooked. More than 90% of watermelon is water; it quenches thirst and hydrates your body.
The fruit is rich in vitamins such A, C, B6 and antioxidants. Watermelon fruits are ready for harvesting when the tendril close to the fruit dries up and turns brown. The fruit gives a hollow sound when tapped.
Common Pest and Diseases.
Anthracnose lesions could form on foliage, rind, fruit or stem.
-Angular dark brown or black lesions on leaves.
-Elongated and sunken lesions on fruit and stem.
Anthracnose is spread through wind and rain.
Anthracnose can be controlled through rotating them with crops not from cucurbit family every 1-2 years. Seeds should also be treated and disease free.
2. Alternaria leafspot
Appear on foliage and leaf of watermelon.
Irregularly shaped dark brown lesions on leaves. Lesions could also be circular black.
Spores on plant debris are transmitted through wind and rain.
Control and management include
– crop rotation
-use of drip not overhead irrigation
– Field hygiene ;bury crop debris deep into the soil.
-Apply appropriate protective fungicides.
3. Blossom end-rot; caused by a nutritional disorder.
– First appearance on immature fruits as small, light, brown spots close to the blossom end of the fruit.
– With fruit growth the spots also enlarge turning into dark leathery lesions sunken on fruit.
Watermelon varieties with long fruit are more susceptible to blossom endrot.
Main cause of the disease is lack of calcium on the developing fruit brought about by disruption of nutrients uptake through root damage, soil salinity, excessive application of Nitrogen fertilizers.( encourages vigorous vegetative growth but reduces calcium in the soil)
Can be reduced through even and regular watering.
Insect is 1.5mm in length and slender
Adult thrips are pale yellow to light brown.
Nymphs are smaller and lighter in colour
-Leaves appear silvery speckled with black faeces.
Control is achieved by avoiding planting of watermelon close to crops such as onions and garlic.
-Use of reflective mulches
– Use of appropriate fungicides.Advertisements