Strawberry growers come and see! Ultraviolet light can kill spider mites
Strawberry is one of the main greenhouse high value-added crops. It is an important problem that strawberry growers need to deal with how to scientifically control the difficult pests such as Tetranychus teratoides, Thistle tea yellow and Thistle west.
New research from the University of Florida in the US has shown that spider mites can be effectively eradicated by targeting strawberry fields with ultraviolet light at midnight. The new findings could provide commercial strawberry growers with a good way to quickly control the crop.
The researchers conducted a field study during the strawberry growing season in Florida in the United States between 2019 and 2020 and 2020 and 2021, using four treatments:
(i) Foliar application of ethyl polygermicide in response to natural pest pressure;
(ii) UV-C ultraviolet radiation, irradiation energy 200 J/m2, twice a week;
(iii) UV-C ultraviolet radiation, irradiation energy 350 J/m2, twice a week;
(iv) Blank control.
In the field experiment, Tetranychus disulata could be observed in the irradiation energy of 350 J/m2 (2020-2021) group. In the other groups, no effect was observed due to the lower natural infection rate. No negative effects on yield were observed in the two groups of UV-C applications.
The results showed that the mites could be effectively controlled by ultraviolet light twice a week in the evening. Sriyanka Lahiri, assistant professor of entomology at UF/IFS, said the study provides scientists and growers with data to dramatically reduce the amount of UV exposure needed to produce spider mite eggs in strawberry fields without reducing fruit yields.
"Another advantage of UV light is that it leaves no residue and can be done using automated robotic devices that are already in place," Lahiri said.
"Because few acaricides (sprays) are effective against pests such as the Tetranyroid mite in strawberries, ultraviolet light provides an effective physical control method that can be used to produce strawberries in the open field and in greenhouses," Lahiri said. "Spider mites, if not managed, are known to damage the leaves by sucking SAP from the leaves and producing silky cocoons that cover plants, causing huge fruit loss."
UF/IFS researchers also demonstrated that strawberry pathogens can be prevented using ultraviolet light.
UF/IFS plant pathologist Natalia Peres says the UV light technology has great potential for growers because it is more effective against pests and diseases present on plant surfaces. Other tools are needed to control pathogens that live in strawberry tissue.