Effective Management Of Fruit fly In Mango

The summer season has already arrived. Are you waiting for your much anticipated mango harvest? Beware farmers! Don’t let fruit flies hinder your mango yield and diminish your profits. With the fruit being the economically valuable part of this crop, it is crucial that you protect it from the pests. Fruit fly (Bactrocera dorsalis), is a serious pest of mango, especially during fruit development and fruit ripening stage. They can infest a significant portion of the fruit, leading to reduced quality and market value. On average, fruit fly infestation can cause yield losses of around 25 – 30%. However, in severe cases, it can cause up to 90% loss. So, take proactive steps by early detection, prevention and management as guided in this article to make your mango season the most bountiful and profitable.  

Symptoms of Fruit fly in Mango: 

To detect fruit fly infestation in mangoes, you should look for the following signs;

• Adult female fruit flies puncture the skin of developed fruits and lay their eggs within the inner flesh. 
• Once the eggs hatch, the maggots consume the pulp of the fruit, causing it to decay and rot. 
• As the larvae feed on the fruit, it may become mushy, discolored or develop brown or black sunken spots/patches. 
• Affected mangoes may show signs of blemishes and shriveling. 
• The internal feeding of the larvae can result in the presence of sticky secretions or gummy exudations on the surface of infested fruits. 
• Small exit holes of larvae can be visible on the fruit skin. 
• Infested fruits rot from inside, leading to a foul smell and deterioration of the fruit. 
• Affected fruits may tend to ripen prematurely and drop off. 

Preventive Measures: 

Cultural:

• Avoid growing alternate host plants near mango orchards such as melons, guava, papaya and citrus. 
• Collect and dispose of any fallen or infested fruits away from the orchard.  
• Expose the pupae to sunlight and eliminate them by ploughing the topsoil of the orchard to about 10 cm depth during Nov – Dec. 
• Plant varieties that mature early, enabling the fruits to ripen during periods of low fruit fly populations.  
• Grow mango varieties with similar growth cycles. 
• Remove weeds around the trees and maintain field sanitation. 
• Remove any wild or old trees in or near the orchard to eliminate the potential breeding sites. 

Mechanical:

• Keep 6 – 8 Tapas fruit fly pheromone trap per acre to monitor and control fruit fly population. 
• For 1 acre orchard, install 4 – 6 yellow sticky traps to catch adult fruit flies which are particularly attracted to their bright yellow colour.  
• Bait traps: Food baits (sugar-based or protein-based) are effective to lure and trap fruit flies.  Use methyl eugenol traps at 4 – 6 per acre to lure and kill male fruit flies. It can be prepared by adding 10 ml of the mixture in a cotton ball (1 ml/lit methyl eugenol + 2 ml/lit Lambda-cyhalothrin) and place it per trap. Other food baits such as yeasts, sugar syrup or ripe/overripe mangoes/banana with poison can also be used to trap fruit flies.  

(NOTE: Time and placement of traps is important to ensure effective trapping. Place the traps during the fruit development stage till the harvest. Also, hang or position the traps near areas of high fruit fly activity) 

Physical Barrier:

• Bag the mango fruits with fine mesh nets or covers to create physical barrier, preventing fruit flies from infesting the fruits. 

Biological:

• Spray neem oil at 2 – 3 ml/lit of water at regular intervals. 
• Introduce natural enemies such as parasitic wasps. 

ITK Practices to control Fruit flies in Mango: 

• Crush 20 grams of holy basil leaves (Ocimum sanctum). Place the crushed leaves along with the extract inside a coconut shell. Then, fill the coconut shell with 100 ml of water. To enhance the longevity of the extract, add 0.5 grams of citric acid to it. To poison the extract, add 0.5 gram of carbofuran 3G. Hang the traps from mango tree branches at 4 traps per tree.  
• Make a trap using a 2-liter disposable water bottle by creating 2 holes on the bottle, 5 cm above its bottom. To hang, thread a string through the hole. Prepare attractant mixture for fruit flies by combining vinegar (1 cup), water (2 cups) and honey (1 tbsp). Shake the mixture and then fill the trap with it up to the level of the holes. Suspend the trap approximately 5 feet high. 

Control Measures: 

For effective management of fruit flies, you have to prioritize preventive measures before resorting to chemical management. Consider chemical control as a last resort when preventive measures alone are not sufficient to manage the infestation. 

Bait Splash:

In case of severe infestation i.e., if you find > 5 flies per trap per day, bait spray can be done on the tree trunk once a week. Prepare it by mixing 100 grams of molasses or jaggery and 2 ml/lit of Deltamethrin in 1 liter of water.  

Biological Insecticide:

Spray Tracer Insecticide at 0.4 ml/lit water. 

Chemical Management:

(NOTE: The above-mentioned insecticides can be sprayed along with neem oil. Check the product’s description to know the right time of application) 

Post-harvest Treatment:

Treat the harvested fruits with hot water at 48˚C for 1 hour. 

Conclusion:  

To protect your mangoes from fruit fly attack, regularly monitor the orchard for signs of its infestation, follow the above-mentioned preventive measures such as good cultural practices, installing traps and regular spray of neem oil combined with chemical management to get rid of the pest attack. By doing so, you can safeguard the quality of the fruits and ensure more yield and profit.