Guava trees produce sweet smelling fruits with an edible rind, with a creamy white, yellow or pink flesh. When ripe, guavas release a sharp, musky odour that draws fruit flies. Fruit flies are among the world’s most serious pests of different horticultural crops due to their direct impact on economy. They are among the most destructive pests. They cause enormous threat to the production of fruits and vegetables throughout the tropical and sub-tropical areas and causes both quantitative and qualitative losses. Fruit flies lay their eggs inside the fruit and the maggots feed on the flesh. As a result fruits rot and infestation often spread quickly.
Most of the damage is caused by the larvae that nourishes inside the fruit during its growth and development. It attack fruits at different stages of maturity but the harm is more noticeable at harvesting stage. The adult female fruit fly place eggs in the flesh of fruits and vegetables. After emerging the larvae feed on the pulp which looks normal from outside. Fruits finally drops down and is not suitable for sale, therefore reduces orchard productivity. During winter the larvae pupate in soil 5-10 cm deep and flies start developing during April onwards, with extreme population during May to July which overlaps with fruit maturity.
Prevention and Control:
Fallen and infested rotten fruits should be removed, as they are capable of spreading further infestation. These should be picked up and destroyed by dumping in a 40-60 cm deep pit and must be covered with soil to eradicate all sources of possible breeding sites. Fruits should be harvested early when they are mature green. Harvesting guavas before they ripen fully is a good practise for preventing infestation. As fruit flies only attack matured fruits, so early harvesting prevents infestation. As this stage of fruit maturity, crops are not susceptible to attack.
Overripe fruits should be also picked as these are ideal breeding sites for fruit flies. Ploughing the topsoil 5-10 cm deep is good for its control. Due to deep ploughing pupae are exposed to predators, parasites, and direct sunlight. Crop and field sanitation is also essential for the control of this pest. Guavas should be avoided to extreme and sudden changes in temperature, moisture, fertilizer or soil pH, as unexpected changes may stress plants and draw fruit flies and other pests.
Pheromone traps such as methyl eugenol capture male flies. Set up methyl eugenol trap in the orchard at the rate of 5 per acre. Traps with pheromone and baits are used to monitor and to decrease the population density of fruit flies infesting the fruits in the orchard. Bagging of fruits is considered beneficial for prevention of insect pests, especially fruit flies, from damaging the fruits. The bag provides physical protection from mechanical injuries and act as barrier against pests.
Fruit fly infestations often spread quickly, but if preventive measures are taken, then the loss can be overcome and its population can be greatly decreased. Almost every guava producers in Pakistan are facing problem of fruit flies attack and their yields are greatly affected. Jazz Bakhabar Kissan service is helping farmers to overcome the losses due to fruit fly attack. Creating awareness among the farmers is very important as mostly farmers are uneducated and they are unaware about the efficient methods to overcome losses. Through the Jazz Bakhabar Kissan Call Centre farmers are able to avail free guidance from the agriculturists and share their problems related to crops and get information about latest technologies and always keep themselves updated.