The mango, (Mangifera indica Linnaeus) is a popular fruit that is rich in vitamins and essential minerals. It is commonly consumed as a fresh fruit, but can also be processed into powder or pulp.
One of the major challenges facing mango farmers is pest infestation which cuts down the yields leading to huge losses.
There are over 400 species of insect pests that infest mangoes worldwide. The most devastating are fruit flies (Bactroceraspp, Ceratitis spp.) and seed weevils.
Other common pests include mealybugs, thrips, mirids, scales, mites, whiteflies, beetles and aphids. These are mostly controlled using conventional pesticides, which have a negative impact on human health and beneficial insects. To increase the effectiveness of these chemicals, farmers resort to routine applications, which cause safety and health concerns, and high pesticide residues in the fruits, leading to rejection in export markets.
As buyers prefer to buy mangoes that are not laced with chemicals, farmers need to acquire knowledge on how they can produce their mangoes without applying chemicals.
Use of synthetic chemical pesticides interferes with the natural biological processes, which balance and keep pests below damaging levels. Farmers should aim to prevent the occurrence of pests by proper management of mango trees and the farms on which they grow.
Below are ways in which you can minimize pest occurrence in your mango farm:
- Use of plant extracts
As has been explained in previous articles on use of plant extracts to control pests, plants such as neem, basil, ginger, garlic and chili can be used to make microbial toxins that kill pests. How to make extracts using garlic and neem.
Using garlic
Materials:
2 garlic bulbs
Few drops of soap
4 cups of water
Grinder or knife
Strainer
Bottle container
How to prepare the extract:
Chop garlic cloves into fine pieces or crush by grinding.
Allow the crushed garlic to stand for 24 hours.
Add water and stir in soap.
Store in a bottle container.
Strain the water mixture to extract the liquid.
Dilute with water to a reasonable concentration.
Shake well before spraying.
Spray thoroughly on the infested plant, preferably early in the morning.
Note: Garlic oil spray affects many organisms. It is non-selective so it can kill beneficial insects as well. It is not recommended for aphid control since it kills the natural enemies of aphids. It should be limited to home and garden applications where natural controls are rarely present.
Neem extract
Pound 500 grams (g) of neem seed kernels in a mortar.
Mix crushed neem seed with 10 litres of water. It is necessary to use a lot of water because the active ingredients do not dissolve easily. Stir the mixture well.
Leave to stand for at least 5 hours in a shady area.
Spray the neem water directly onto vegetables using a sprayer or straw brush. Neem water can be stored and will remain effective for 3 to 6 days if it is kept in the dark.
2. Commercial biopesticides
Some companies such as Osho industries and Real IPM have collaborated with scientists to produce and sell biopesticides made from organic material. These biopesticides are free of synthetic chemicals as they are made from plant extracts or from microbes. (bacteria, viruses, or fungi) found in air, soil or water. These biopesticides can either kill one or several targets, but they have no effect on human beings and beneficial organisms in the farm.
One of the biopesticide that you can use in your farm to control mango pests (fruit fly, thrips, and mealybugs) is the Metarhizium anisopliae. Real IPM (Kenya) has been working in collaboration with the International Centre of Insect Physiology and Ecology (Icipe) and has come up with products made from metarhizium such as: Metarhizium 69, Metarhizium 78 and Metarhizium 62.
Metarhizium is a naturally occurring entomo-pathogenic fungi (a fungi that works like a parasite that kills the pest). When applying it, follow instructions on usage of water as too much water affects its effectiveness. Metarhizium spores germinate and colonise the pest, killing it in 2 to 4 days. Metarhizium is compatible with various fungicides and insecticides. Additionally, it is not harmful to natural enemies. These biopesticides can be obtained from Real IPM. Contacts are provided below.
Insert a photo of the biopesticide
3. Cultural practices (orchard sanitation)
If left unattended, pests can multiply in your mango farm and affect all the mangoes leaving you with nothing to harvest. Once you cite any affected mangoes (mangoes with dimples and oozing a clear sap) handpick them while they are still hanging. Waiting for them to fall on the ground has an increased risk as the maggots may have left the fruits to pupate. After picking the fruits, you can feed them to pigs or poultry, or dispose them off in black plastic bags, under the sun to allow the maggots to die. Alternatively, you can burn or bury the collected fruits. Ensure to bury them about two feet deep to prevent the adult flies from emerging onto the surface.
4. Physical control
Physical controls include bagging of fruits to prevent pest damage and use of light, pheromone, or bait-loaded traps, that lure pests and kill them.
Bagging fruits
Bagging prevents fruit flies from laying eggs on the fruits. Take papers such as newspapers and fold them in a way that they look like a balloon. You can use glue or any sticky material to make the shape. Blow into the bag to inflate it. Insert each mango fruit per bag and tie at the top firmly. Adjust the paper to ensure that the fruit is not in contact. When using plastic bags, open the bottom or cut a few small holes to allow moisture to dry up. Moisture trapped in the plastic bags damages and/or promotes fungal and bacterial growth that can cause diseases. Plastic also overheats the fruit. Bags made of dried plant leaves are good alternatives to plastic. For tall trees use a climbing ladder and bag all the fruits. Your bagged mangoes will be protected from pests and physical damage, and therefore have a quality appearance, for the market.
Insert a photo of bagged mangoes
Use of bait-loaded traps
One way of monitoring pests in your mango farm is by placing traps that attract fruit flies on strategic places on the mango trees. Icipe has developed one such trap, the fruit fly trap, also known as a bucket trap.
This trap is cheap and easy to make. It is made of a cylindrical plastic container with 4 holes evenly spaced on its sides, a lid, a wire hanger and a bait basket (if it is to be used with a dry attractant). Similar traps can be made locally using ‘Kimbo’ or ‘Blue Band’ containers or similar plastic containers or plastic bottles.
Place a photo of a handmade fruit-fly trap
They can be used with food baits such as yeast, a piece of fruit (banana, mango) or vinegar. Food baits attract both males and female fruit flies, they are not species specific, and also attract other insects, including natural enemies.
A simple fruit fly trap is made as follows:
- Take a plastic bottle
- As bait, use 1/2 cup vinegar, mix with water
- Add 4-6 drops liquid dish soap (it heavies down the wings and the fruit flies drown), do not stir
- Then take a pen or pencil and poke 4 to 5 holes in the plastic, just big enough for a fruit fly to fit into, about 7mm. Once a fruit fly crawls in, it cannot get out. You would think they would just fly back out through the holes, but they will not! If you see fruit flies crawling around on the surface of your plastic container but not going inside, make the holes larger.
- Hang the bottle in an area where you have seen most fruit flies. Depending on the amount of fruit flies you have, you can expect to start seeing the bottle fill up within just a few hours.
The trap is filled with bait and hanged on the tree about 2 to 4 m above the ground within the canopy layer, in a semi-shaded spot, preferably in the upwind part of the canopy. The trap should be hanged in such a manner that branches and leaves are nearby, but not touching the trap. Traps should be hanged 10 to 50m apart, depending on the bait used. Collect catches weekly and sieve them.
You can also purchase the fruit fly trap from Real IPM (0746354037), Farmtrack Consulting Ltd (0711495522) and Kenya Biologics (0704652032). I