The Huanglongbing disease, or HLB, is considered the most destructive citrus disease and, so far, there is no cure for it.
For years, the producers from Tucuman have been concerned about this disease, as they know that the bacteria, which is transmitted to the fruit by an insect called Diaphorina citri, can seriously affect one of Tucuman's most important economic sectors.
Given this, researchers from Tucuman are developing a sensor to detect the disease early and, thus, prevent it from spreading to new crops.
The method proposed by researchers at the National University of Tucuman (UNT) and CONICET aims to detect the disease in its initial stage in the fields. The device is based on the detection of markers associated with the disease. It works by means of a chemical reaction that detects the substance that citrus fruits produce in the presence of HLB.
The research, which is the result of Matías Trujillo's doctoral thesis and is being directed by the doctor in Bioengineering and CONICET researcher, Rossana Madrid, is being carried out at the Laboratory of Media and Interfaces of the Faculty of Exact Sciences and Technology (FACET). Martín Zamora of the same Institute, María Paula Filippone of the Faculty of Agronomy and Zootechnics (FAZ), Carlos Grellet Bournonville of the Institute of Agroindustrial Technology of the Argentine Northwest and Lorena Sendín of the Institute of Agroindustrial Technology of the Northwest of Argentina complete the research team, according to the UNT News website.
Laboratory tests were successful and now field trials have begun. The researchers had to travel to the state of San Pablo, Brazil, which is affected by the disease, to test the device in cultures infected with the HLB and perform tests directly on the plants. In Argentina, the disease is present in small foci in the NEA and in Santiago del Estero making it difficult to carry out tests in the different stages of infection of the plants.
The tests are based on preparations that contain chemicals that cause a color response, in the presence of the disease in crops. However, these chemicals will soon be applied to a biosensor, i.e. a device that has a biological component and a physical one. It will be shaped like a test strip, similar to the ones used in pregnancy tests. A substantial advantage of this device is that it will be easy to apply and interpret.
The biosensor will be placed in each plant and yield results in a matter of minutes or hours. The results will be displayed in a range of three colors that will indicate if the sample is positive for the disease, negative or doubtful, without the need for specialized personal. "Currently producer identify the disease via the visual identification of symptoms, but this is only possible when the disease is very advanced. Molecular diagnostic techniques are also used, which are not immediate. Samples must be taken to the laboratory and it requires using complex instruments and trained personnel," Madrid stated.