Brazilian researchers developed natural repellent against psyllid categories: agrochemicals, Environment, Greening, Productivity, Research, sanitary control, Sustainability, technology

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Substance made from guava leaf can be an effective weapon to help in the control of citrus greening

A natural repellent removed from the guava leaf may be the solution to control citrus greening, considered one of the worst diseases of citriculture in Brazil and in the world. The product is being developed in a partnership between the Federal University of São Carlos (UFSCar) and the Fund for Citrus Protection (Fundecitrus), and it should start to be tested in the groves soon.


The disease is caused by a bacterium that is transmitted by an insect vector, the psyllid. Because it is too small and difficult to identify, it easily enters the groves. If the plant is infected, it has to be eliminated. And because of that, the group of researchers began to investigate natural pesticides capable of repelling the psyllid and attract them to another area, without harming the environment and human health.

They discovered a molecule in the guava leaf that has this attribute. “Our research looked for natural volatile compounds, which are the odors. Our strategy is to use these compounds to repel the insect from the grove to another area, where we can apply pesticides in a more rational way, and also to avoid contaminating the environment,” explained Fundecitrus researcher Mr. Rodrigo Facchini Magnani.

The research in laboratory has already been completed. The next step includes studying the effectiveness of this repellent in the field. “To check if it really works as a repellent and then incorporate it into citrus greening management,” said Mr. Magnani.

The latest Fundecitrus data showed that 16.73% of the groves in the state of São Paulo were affected by the disease last year, with around 32 million infected trees.