A nano-insecticide could bring much-needed hope to growers in the battle against citrus greening. Researchers at Brazil’s Embrapa Meio Ambiente (SP) and the Chemistry Institute of the State University of Campinas (Unicamp) have successfully controlled the vector responsible for its spread using a controlled release system for the thiamethoxam molecule.

Thiamethoxam is the ISO common name for a mixture of isomers used as a systemic insecticide.

The new product uses polymeric nano micelles, structures smaller than a billionth of a meter, to encapsulate the active ingredient.

Studies indicate that nano-pesticides can surpass conventional pesticides in effectiveness and environmental safety. The project was supported by the São Paulo State Research Foundation (Fapesp).

Control of greening and benefits of the nano-insecticide

The effectiveness of the nano-insecticide was evaluated in the control of the psyllid (Diaphorina citri), the insect vector of greening (huanglongbing), a serious disease that affects citrus plants and has no cure. The use of nano-insecticides can reduce the number of applications needed, reduce pest resistance, and minimize environmental impact and costs.

Ljubica Tasic, a professor at Unicamp, pointed out that the product showed low toxicity to aquatic organisms. 

“This demonstrates how nanotechnology can promote more sustainable agricultural practices, guaranteeing agricultural production and quality of life for future generations,” said Tasic.

Thiamethoxam and the challenges of greening

Greening is one of the most devastating citrus diseases, due to the rapid spread of the bacteria by the insect Diaphorina citri and the lack of genetic resistance in citrus plants. Thiamethoxam, used to control the disease, belongs to the class of neonicotinoids, insecticides that are highly soluble in water and susceptible to leaching and photolysis.

Advantages of nanoencapsulation

Nanoencapsulated pesticide formulations allow for controlled release and protect against premature degradation, making the use of insecticides more efficient and sustainable.

Further studies on the impacts on humans and the environment are essential for the safe implementation of this technology in agriculture.