Case studies by crop · Permanent crops

Peach orchard: aphids (Agras T20)

DJI Agriculture case study, collected by FLYDROPS.

In a peach orchard in Shanxi province, China, an outbreak of aphids threatened the crop. An Agras T20 sprayed with slow flight and a large water volume, and within 72 hours mortality on the leaves exceeded 95%.

Aphids on trunk and branches before the application.

At a glance

Location	Taigu District, Shanxi Province, China
Crop	Peach trees 10–15 years old, 2 m high, 3 m crown diameter
Drone	DJI Agras T20, Fruit Tree mode
Date	3 June 2020
Pest	Aphids, up to 800–1,000 per leaf
Evaluation	District plant protection station, 72 hours later

The study uses the T20, 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

Aphids had overrun leaves, trunks and branches, with up to 800–1,000 on the back of a single leaf. The leaves curled, withered and turned black. The cause was inadequate management and unfavourable weather. In an orchard, the hard part is getting the spray onto the back of the leaves.

The drone above the tree crowns.

What was done

The test was part of DJI Agriculture’s “Standard Operation Code for Plant Protection Machinery in Orchards” project with the Center for Chemicals Application of China Agricultural University, supervised by Professor Wu Zhiming (Shanxi Agricultural University). The parameters were chosen for the severity of the infestation:

speed 2 m/s: low, so enough product reaches the back of the leaves,
route spacing 4 m: peach trees have a thin crown up to 4 m wide,
volume 75 L/ha: increased because of the very large aphid population,
height 2 m: enough for the spray to penetrate the crown, given the T20’s weight and the wind.

The results

Where measured	Aphid mortality after 72 hours
Front of leaves (severe infestation)	Above 99%
Back of leaves	Above 95%
Trunks	Above 99%

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

No overlaps or misses were found in the field and the application was uniform. Note that conditions were ideal (no wind, 30 °C, 80% humidity). In stronger wind the study advises a lower height, and stopping once the wind exceeds a gentle breeze.

What it means for Greece

The peach is an important crop in Greece, particularly in Imathia and Pella, and aphids are a common problem in stone fruit. What is useful here is not the product (which concerns the Chinese market and is not listed) but the logic of the settings: slower, lower and with more volume when the foliage is dense.

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.