Between the cultivation of grain and its consumption lies the real work of farmers, as the growth of the plants must be constantly monitored, the soil quality checked and insect pests eliminated. These are time-consuming and cost-intensive processes. In order to modernize such processes, the Fraunhofer Institute for Reliability and Microintegration IZM is involved in the ZIM network 'AgriPhotonics' together with the TU Berlin. Here, 29 German and Israeli partners from industry and research have joined forces to establish digital processes in agriculture using the potential of agricultural technology and photonics.

Usually, agricultural storage facilities are fumigated with the help of chemical substances after a pest infestation. However, poisons such as hydrogen phosphide, which are lethal to insects, can only be used a few times, as more frequent use leads to residues forming on the stocks, which pose a health risk to humans and, above all, to environmental pollution.

In order to reduce the use of chemical preservatives, researchers at Fraunhofer IZM have set themselves the task of combining laser technology and automated image recognition to reliably ensure the protection of agricultural products. The project was coordinated by the Julius Kühn Institute in Berlin.

Laser system to render harmful insects harmless.

© Fraunhofer IZM

In the predecessor project 'Insect Laser', a solution was developed with funding from the Federal Office for Agriculture and Food and partners at Fraunhofer IZM to protect agricultural supplies from contamination by grain weevils and dry moths. These pests, which are just 4 mm in size, can cause considerable economic damage and transmit diseases.

In the current project, the researchers recognize the moment of infestation before the pests can spread in the stocks. Using an image processing method developed by BTU Cottbus, the small pests are detected on the surfaces of the supplies or on walls. An AI system then analyzes and classifies the insects and compares them with reference images. Such algorithms for image recognition are already established in countless applications. However, the very different dimensions were particularly challenging in this project, as the pests, which are only a few millimetres in size, have to be reliably detected in very large warehouses. The Fraunhofer IZM had to take this into account when designing and creating the laser system.
Once the position of a pest is known, a fine laser beam is directed by radio via a scanner to the relevant coordinates, rendering the grain weevil or dried fruit moth harmless. Due to the low temperature and intensity of the laser, the supplies underneath are not affected. By using a laser system, the direct primary infestation is prevented so that insects that are harmful to stocks do not spread in the first place.

The researchers at Fraunhofer IZM in Berlin have investigated how different wavelengths and intensities of the light beam influence the movement behavior of stored product pests. They found that infrared light has the least effect on the movement behavior of the animals, which is characteristic for identification. Secondly, they played a key role in the development of the laser system: Initially, they produced a laboratory setup. After successful tests, they transferred this setup into a compact insect laser system consisting of several units for use in experimental cells. They also developed the software and hardware interfaces between the camera, laser and scanner.