Fruit fly’s Attack on Citrus Fruit

Fruit fly attacks citrus fruit
Fruit fly attacks citrus fruit

Fruit fly (Bactrocera spp) is one of important pests in citrus. The damage caused by its larvae trigger early fruit abscission. This causes loss of yield and decrease in fruit quality. The attacked fruits could be identified easily due to change in fruit skin color around the part where the fly pricks which decaying fast. Within the area, there could be found a small hole. This is due to the larvae that live inside the fruits that make the fruit decays. If it is cut, the larvae will be seen and jump around when touched.

In citrus, fruit flies attack pummelo (Citrus grandis) more and less on sweet orange (C. sinensis) and other type of citrus. Fruit flies cause 30-60% loss on pummelo which sometimes the attack also combined with fruit borer (Citripestis segittiferella) then makes them difficult to distinguish. There are four types of fruit flies found in Indonesia that are B. Carambolae, B. Papaye, B. Dorsalis dan B.Cucurbitae.

Fruit flies are sensitive to unfavorable environmental conditions. At optimal environmental conditions, it could produce high population. The optimal temperature when they produce high population is at ± 26 ° C with a relative humidity of 70%. Soil moisture is very influential on the development of the pupa. Soil moisture best for pupa stage is between 0-9%. Light has a direct influence on the development of fruit flies in which the female will lay eggs faster in bright conditions, on the other hand the pupa will not be an adult when exposed to light.

Based on the results of monitoring, fruit fly control can be done in several ways. Technology that can be applied are:
• Physical control by wrapping the fruit from the age of 1.5 months to prevent oviposition (egg laying) on ​​the fruit. Wrapping can be performed using paper or plastic bag.
• Sanitation garden, destroying damaged fruits both that are still in the plant or fall on the ground by buried or burn it, with the aim to get rid of the larvae in the soil.
• Use of attractants / male fruit fly trap with Methyl eugenol (ME) combined with insecticide to capture and simultaneously controlling male flies.
• mechanical control by put soil under the canopy and fogging regularly to inhibit the stage of pupa becomes adult and to repel adult flies.
• By releasing sterile fruit fly produced by radiation techniques. This control is still an expensive control.
• Biology control by the use of parasitoids and predators that exist in nature like Biosteres sp., Opius sp., Ants and spiders

How to make and install the trap

The relatively simple and inexpensive way to create a fruit fly trap is to use the drinking bottle/container that has cone-shaped neck. Conical tube sections are cut, reassembled in reverse, the mouth part faces the inside tube then all parts are sticked to each other by glue or tape.
Attractant or trapping substance is put on twisted cotton about the size of thumb and then tied with a small wire such that it is hang in the middle of the tube traps. Attractant material is put on the cotton just enough to avoid dripping. Hang the trap on a branch or twig on the tree canopy. Trapping conducted begins when the fruit still small (age 1.5 months) until the fruit harvest. Reapplying of the attractant should be repeated every month. Each hectare of plantation requires about 15-25 traps.

Fruit fly trap installment
Fruit fly trap installment

Translated by: BDM

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