Recently, I was on a tour of a watermelon farm and the farmer informed me that they were struggling to control water melon flies.
Here are simple ways to control this vicious pest.
The fly attacks the fruits by developing a water soaked appearance which results in rotting. The attack, reduces the export potential of the fruits.
Melon fly attack spreads fast due to the fact that one female fly may deposit up to 1,000 eggs.
Because of their high egg laying capacity and mobility, each female is capable of destroying large numbers of fruit in her life span.
Additionally, melon flies are strong fliers and able to travel long distances. Adults spend considerable time on low, succulent, leafy vegetation surrounding cultivated areas.
The flies hide in the foliage on any dense plant, bush or tree, sometimes a considerable distance from host plants. During hot days, they rest on the underside of leaves or in shaded areas hard to reach during chemical control.
Chemical control of the melon fruit fly is relatively ineffective. It is therefore recommended that an integrated approach is adopted to manage the spread.
Plant a trap crop around the water melon field.
A trap is a crop planted to attract insect pests from another crop.
It is also known as a sacrificial crop; this plant when added to your garden will attract pests away from the main crops.
The reasoning is simple: just as children will choose ice-cream over a plate of vegetables, likewise most garden pests have preferences for what they like to live on.
By planting rows of a trap crop (the ‘ice-cream’) near to your vegetables the pests will be attracted to the trap crop and will leave your main crops alone.
Trap cropping are significantly cheaper than chemical control methods.
Additionally, the pests have often evolved resistance to commonly used pesticides, which requires some alternative control strategies.
Melon flies rest under the leaves of crop such as maize, cassava and pawpaw.
Plant this trap crops around the filed to trap the melon flies.
If the field is bigger, plant the trap crop in row leaving enough space for your water melon.
Field sanitation. This is an important and highly effective farm practice to keep melon fly under control. Remove and destroy all the potential sources of pest infestation and weeds from the field.
Keep weeds under control at all times.
Keep the surroundings of your farm free of weeds, unless they are maintained and intended as habitat for natural enemies.
All the infested fruits should be properly disposed by placing them in a sealed plastic bag and buried deep in the ground or burnt.
Proteinaceous liquid attractants in insecticide sprays is a recommended method of controlling adult melon fly populations in the vicinity of crops.
The bait insecticide sprays are applied to broad leaf plants that attract adult melon flies.
Baits encourage the adults (especially females) to feed on the spray residue and can provide good rates of kill. This method prevents the female from laying eggs thus controlling the population of fruit fly.
[The writer is an expert on agricultural solutions and sustainable agriculture]