Farming 101Instructional MaterialPests and DiseasesvaMudhumeni

Production of Water melons in Lowveld

By Floyd Fambisai

Lowveld areas experiences very high temperatures in summer of over 40°c  with warm winter season, rainfall is  less than 300 mm per annum the areas  covers Chiredzi, Save, Beitbridge, Gwanda, Hwange Kariba and other pockets of Zimbabwe.  

Land preparation

The area should have ridges made spacing at 2 m apart depending on varieties to achieve plant population of 4000-8000 plants per ha.

Time of Planting

Water melons could be planted all year round in the Lowveld but end of July to early August plantings which are for October, November and December market fetch the highest prices.

Varieties

Crimson sweet, Congo, Tiger, Charlson grey. Yield of 5 to 72 ton/ha could be achieved under good management.

Fertilization

Water melons have less nutrient requirement as it has of its deep rooting system. Application of compound L (4:17:11) or Compound C (5:15:12) as basal fertilizer, top dressing of Ammonium Nitrate (34.5 % N) also they reacts positively to previous applied manure.

Irrigation

Furrow irrigation is the best option in the Lowveld as it will not expose the fruits to moisture resulting in cracking of fruits during high temperatures.

Weed Control

Shallow early mechanical cultivation and hand-hoeing are needed to control weeds before plants have developed vines as disturbing vines induce stress, can spread disease and cause flower drop.

Pests and diseases

Fruit fly causes rotting of the fruit by laying eggs during flowering usually seen early fruit drop and rooting caused by larvae to control use Malathion 25 WP

Aphids Found underside of the leaves signs

Fusarium wilt Affects vines of the plant, may cause wilting of the plant use Benomyl 50 WP

Powdery mildew and Downey mildew fungal infection which affects the to control use wettable Sulphur and Copper Oxychloride85 WP

Damping off The failure of infected seeds to germinate.

Physiological disorders these are non-pathogen agents that affect fruit aesthetic quality and reduce the yield, causes are environmental, genetic or nutritional factors.

Misshapen melons

Common in varieties with long elongated fruit caused by moisture stress aslo when the fruit lie on uneven ground or were damaged by pest or mechanically when small. Misshapen or pear-shaped fruit can also be caused by poor pollination that leads to restricted growth at the stem end because of the absence of developing seeds which can be reduced by introducing beehives in the field.

Bursting

This usually results from an uneven growth rate, which is particularly associated with heavy rainfall or irrigation when the fruit is maturing soon after hot conditions more prevalent in Lowveld.

White heart

There will be white streaks or bands of undesirable flesh in the heart the fruit ussually caused by excessive moisture and too much nitrogen during fruit maturation.

Hollow heart

Disorder that varies among varieties so genetic related though could be a response to unideal growth conditions

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