Melons: Use preventative spray to control pests and diseases

With a medium-sized fruit going for between sh5,000 and sh7,000, watermelon is a real money maker.

There are many types of watermelons on the market.

However, farmers are advised to select varieties that mature early, resist several challenges and yield well.

The market has both open-pollinated varieties (OPVs) and hybrids. Some hybrids produce fruits that are as large as 5- 10kg. The market for the fruit can be found in the St Balikudembe market, Nakasero, Kalerwe, Nakawa and regional markets across the country's big towns.

Melons are always attacked by fungal diseases, such as powdery and downy mildews. Therefore, preventive sprays should be employed often, using fungicides such as copper or mancozeb.

Spraying can be done once a week during the dry season and at least twice during the wet season.

Use 70g of mancozeb in 20 litres or 50g of copper in 20 litres.

Pests

■ Aphids and melon fruit flies are the major pests that attack melons. Aphids suck sap from the leaves, leading to curling and drying of the leaves, which eventually leads to the death of the plant. Dusban always works effectively to kill the aphids.

■ Melon fruit lies mainly manifest at the time of lowering. The adult lays eggs in the lowers, which develop into larva (maggot) at the time when the fruit has been formed.

The larva eats up the cells of the fruit and bores out of the fruit in order to pupate, since it pupates in soil.

This results in fruit abortions, rotting and bursting when the fruit is not yet ready.

Insecticides that control fruit lies at this stage also kill the bees, which we need for pollination.

The best remedy for melon fruit flies is to use fruit fly traps, which attract only the fruit lies and kill them without affecting the pollination activity of the bees.

15 pieces of melon traps should be enough for an acre of land.

Each costs averagely sh20,000.

Harvesting

Melons are ready for harvesting from 75-90 days after transplanting, depending on the variety.

Watermelons are harvested as close to full ripeness as possible. This is when the fruit surface touching the ground is light yellow or when the vine closest to the fruit is starting to wilt.

The peduncle is cut off to prevent it from ripping into the skin of the fruit, which can result in secondary diseases.

Watermelons are prone to cracking or bursting during and after harvest due to rough handling. Therefore, they should not be thrown during handling, stepped on or stacked too high.

If they are transported on a truck, leave no room for shaking during movement as this may produce cracks and once it is cracked, it starts rotting straight away.

Compiled by Joshua Kato (editor Harvest Money) and Abbey Kazibwe (director, Nsanja Agro-chemicals)