Fruit flies cause direct and indirect damage to horticultural crops worldwide and cause severe fruit losses – up to 100% of the fruits – if not controlled at the right time and in the right ways. Fruit flies are very harmful in the larval stage and may lead to reduced productivity and quality of many types of agricultural crops and therefore affect fruit exports.
A – The adult insect (fly) after coming out of the cocoon.
B – Mating: Adult insects mate after 4-10 days
C – The eggs: Batches of 3-8 eggs are laid. After 3 to 12 days, the eggs hatch depending on the climatic conditions and the presence of plant hosts.
D – The adult female lays eggs inside the fruit at a depth of 2-5 mm.
E – The larva (the harmful phase) grows inside the fruits and feeds on their content until the fruits decompose and fall to the ground, then the larva comes out of the fruits and enters the soil.
F – The cocoon: It is located inside the soil at a depth of 2-5 cm. For 10-20 days according to the weather conditions.
Despite the dangers of this pest, the fight against it is still based on the use of traditional insecticides, which have a detrimental impact on the environment and human health, in addition to the fact that traditional control of chemical compounds has not yet yielded satisfactory results. The costs of spraying and the environmental damage to which the orchids are exposed and traces of pesticides on the fruits are all worth mentioning. What makes the problem worse is the use of chemical compounds of unknown sources and weak effectiveness, which lead to the emergence of agents that are resistant to these compounds, leave traces on the fruits and poison the consumer. Hence the importance of developing an effective management strategy.
It is necessary to monitor fruit flies using appropriate and attractive traps and products, to detect their numbers and therefore adopt the relevant management techniques.
Importance of Insect traps
– They help with the early detection of fruit flies, in order to deal at an early stage with sudden increases in the pest community and provide daily and quarterly information on the evolution of the pest community.
– They help to make better farming decisions and improve control results as they will be implemented in a timely manner according to the stage of the pest and its intensity.
– They help to protect the environment, improve the quality of the crop and produce clean fruits that are free of residual pesticide or have them within permissible limits.
– They quickly deal with the growing pest populations and keep them below the economic threshold which can help prepare for integrated pest management programs.
Insect traps can be used to control and collectively hunt the largest number of pest individuals. Traps that contain insect attractants at a rate of 5 – 6 traps / acre, are constantly monitored and their attractants are replaced when necessary. An insecticide can be added to them to increase efficiency and many experiments have proven the effectiveness of insecticide traps and collective hunting in reducing the rate of fruit fly infestation to feasible economical levels.
The most important food attractants used in fruit fly traps
Fruit flies are attracted to the sugar and protein content of fruits, and thus, adult-attractant compounds have been made in a way that mimics these fruits, and female-biased attractants (natural, synthetic, liquid or dry) which are commonly used are based on food, or odors of plant hosts.
The most important attractants used in monitoring and hunting fruit flies are:
– Protein Hydraulics: A non-specialized food attractant used to attract all types of flies and attract both sexes. It is used in the case of few insect communities and for collective hunting.One of the disadvantages of this compound is that it attracts useful types of insects such as parasites and predators.
– TML (Trimedlure)Its taste is attractive to male fruit flies and does not attract females. Classified as a parapheromone, a biochemical pesticide compound, it attracts various types of ceratitis including C. Capitata. It is used in collective hunting with the aim of hunting males and depriving females of mating and is considered more accurate and efficient than protein hydrolases. This attractant is important to detect the first appearance of insects and the abundance of their society.Parapheromones are generally highly volatile and have to be changed every week. Recently, the production of attractant compounds therefrom that last longer started, for field and trap uses.
– The Femilure A female attractant that is effective for a long time (90 – 120 days) so it can be used earlier in the season.Femilure is one of the most important compounds used in fruit fly control programs worlwide as it targets the harmful phase (females).
– 98% ammonium phosphate DAP: A food attractant for adult fruit flies of both sexes. Ways of use: dissolve 50 g of DAP ammonium phosphate in 1 liter of water. It demonstrates effectiveness between one and two weeks, however its dry form lasts up to three months.
Experts in this field are working on producing highly specialized food attractants for females and a specific number of males to avoid conflict with the sterile male technique applied in some countries.Males and females of sexually immature fruit fly adults are more attracted to food traps, which increases the efficiency of food traps. The above-described specialized parapheromone attractants are not commercially available, and some of them can be obtained from the departments and units representing the Ministry of Agriculture in Syria.Some home-made recipes can do the same job and attractants can be made in case the specialized ones were unavailable, however some recipes may work better with certain types of fruit.
It is possible to try some recipe combinations, analyse the results then compare them with specialized attractants with the help of a specialist. Recipes that include sugar, fruit juice and apple cider vinegar are usually helpful.
Examples of attractant recipes for fruit flies:
- (100 g sugar – 2 g dry yeast – 1 liter of water)
- (5 g of vanilla extract – 20 ml of household ammonia – 50 g of sugar – 1 liter of water)
- Peels of tangerines or oranges – 50 ml of household ammonia – 1 liter of water
- (1 teaspoon Borax – 1 teaspoon sugar – 2 teaspoon bran – 1 liter of water)
- (1 liter of hot water – 1/2 tablespoons of ammonia – 1/2 teaspoons of vanilla extract – 100 g of sugar – 1 teaspoon of dishwashing liquid – 1 teaspoon of vegetable oil)
When using water in the preparation of baits, compounds can be added to prevent the evaporation of the attractant-solution during summer and in hot areas provided that they do not affect the effectiveness of the baits (namely propylene glycol at a concentration of 10%).
Commonly used Fruit fly traps
Insect traps are the hunting tools of the targeted insects. They function according to the behavior of the pest and the attractants used on it. The traps vary a lot in terms of their forms and way of work. Other types of innovative traps may achieve similar results and can be used to catch fruit flies.
Three types of traps are used:
Delta traps, dome traps, or home-made traps from empty plastic bottles.
Dry traps
The flies are caught on an adhesive board or are killed using a chemical agent, an example of which is the delta trap.
Wet traps
The flies are caught and submerged in the solution of the attractant or in the water to which surfactants are added. The McPhail Trap is one of the most widely used traps.
2 way-traps (dry and wet)
These traps can be used either dry or wet, and a common sample is the Tephridae trap.
Use the trap in the most efficient way
– The traps are installed before the fruits begin to set
– The food trap is placed at a height equivalent to two-thirds of the height of the tree or the height of the treetop and is fixed on strong and durable branches (in the shade)
– The trap is placed in a well-ventilated place that does not hinder the movement of the targeted insects (not covered with plant branches) and should be well shaded, away from prying eyes.
– The trap is best placed in a field with several hosts and can be of the same type but of different varieties.
– When trees are small in size and do not have enough shade to put traps, it is advisable to place them on or nearby trees, even if they are not fruitful.
– Avoid sick and weak trees and those infected with insects that secrete the honeydew.
– When checking the traps, they should be carried with caution and captured insects should be carefully checked to avoid the escape of live insects in the trap.
– The traps should be monitored weekly before the setting phase and twice a week when the ripening phase begins.
– We recommend to register the numbers of insects and insect species in the farm records.
– The trap should be well cleaned when reused, especially the transparent part of the trap and the old bait should be thrown away. Care should be taken not to pour it on the soil in the field to avoid attracting insects and disturbing the traps.
Insect traps are environmentally friendly, non-toxic tools that achieve natural pest management and are easy to use, recyclable and may be used during multiple seasons.One of the most commonly used traps is the Dome Trap or McPhail Trap, the fruit fly trap or Tephridae trap. The McPhail Trap: The typical and simplified form of this trap consists of a solid, transparent upper part and a bright yellow base. The trap can include a mesh container in which a specialized pheromone of the targeted insect is added along with the food attractant to increase effectiveness.These traps are used to monitor fruit flies and can be put in large areas for collective hunting.
The Tephridae fruit fly trap: The trap was designed at Russell IPM using 3 small funnel entrances on the sides of the trap and is designed in a distinctive way to increase the effectiveness of insects’ entry and prevention of their exit. These traps are used with solid and liquid attractants.
It is possible to make a simple insect trap from the available water bottles and a wire to hang on the tree. 4 holes are made in the top third of the bottle with a diameter that is enough to make the fly enter (0.5 – 1) cm approximately.