Case studies by crop · Permanent crops

Fruit fly baiting (Agras T40/T50)

DJI Agriculture case study, collected by FLYDROPS.

Fruit flies (Tephritidae) lay their eggs inside the fruit and threaten citrus, stone fruit, mango and more. In South Africa, where the application is repeated every 1–2 weeks, the Agras T40/T50 cover 120 hectares a day, against 50 by motorbike and 2 by hand.

Bait spraying by drone in a citrus orchard.

At a glance

Location	South Africa (information from 360° Drone Solutions)
Crop	Citrus (example), stone fruit, mango, pome fruit, berries, melons
Drone	DJI Agras T40 and T50
Application	Protein bait, every 1–2 weeks in the fruiting season (up to 8 months)
Why it matters	Eggs found in export fruit can lead to long bans on sales

The study uses the T40/T50, an earlier generation. The current range is DJI Agras T100, T70P, T55 and T25P; find which one fits your acreage or compare the models.

The challenge

The fly reduces the quality and value of the fruit and, in exports, a finding of eggs can close a market. Traditionally the bait is sprayed by hand or from motorbikes. Both methods have poor penetration, high cost and risk to the operator, and neither guarantees regular, timely coverage. After rain, motorbikes must wait for the ground to dry.

What was done

Because the bait attracts flies by the smell of protein, it does not need to cover all the foliage. The study’s recommendations for the T40/T50 are:

total volume 2–4 L/ha,
droplet size 500 µm (the maximum), for longer life and less evaporation,
route spacing 12 m,
height 8 m,
speed 25–36 km/h,
one application per week,
temperature up to 30 °C and wind up to 15 km/h.

It also mentions modified nozzles for larger droplets, with a note that they are not covered by DJI’s warranty.

The results

Measure	Agras T40/T50	Motorbike	By hand
Daily coverage	120 ha	50 ha	2 ha
Work-rate gain with drone	—	+140%	+590%
Water volume	2–4 L/ha	20 L/ha	Inaccurate

The numbers come from the study and relate to that specific application.

Other advantages mentioned: operation on slopes of up to 50°, uniform coverage of the canopy and spraying right after rain, since the drone does not touch the ground.

What it means for Greece

In Greece the Mediterranean fruit fly (Ceratitis capitata), one of the Tephritidae, attacks citrus and stone fruit, and the bait method is well known. This study, however, is from South Africa, with a different regulatory framework. Here the rules for aerial applications apply (see below), as do the product instructions. The value for you is the logic of the application: settings, weather and frequency.

Rules and responsibilities

In Greece, applying plant protection products from the air, drones included, is prohibited as a rule and allowed only by derogation with a special permit. The study shows what happened in another country; it does not mean the same application is allowed in Greece. The product label always applies, and we do not repeat doses or products here. See the framework in the spraying drone buying guide and confirm it with the competent authority.