HEPIA
School of Engineering and Agronomy of Geneva

Study on the application of UVA - UVB - UVC radiation
against various pests and pathogens

Results
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Regarding mite infestations on the apical part of the plants, the treatment using a wavelength of 310 nm with a dose of XXX mJ/cm2 showed the lowest proportion of mite attacks, with 80% of the plants remaining healthy.
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In contrast, the Armicarb® treatment recorded the lowest proportion of uninfected plants, with only 40% of them remaining free from attacks.

Concerning the trial on Cannabis, the UV treatment that produced the highest proportion of healthy plants (without powdery mildew) is that using a wavelength of 310 nm with a dose of XXX mJ/cm2, showing a rate of 90% healthy plants (p = 0.009). This proportion was not statistically different from that obtained with the Armicarb® treatment

The objective of this work is to test three UV lamp prototypes with wavelengths of 222 nm, 275 nm and 310 nm, made available by the company Future of Grow (FOG) based in Aigle, Switzerland. The aim is to determine the effectiveness of these luminaires in controlling various pests and pathogens, specifically powdery mildew and mites, on strawberry and Cannabis crops.

This work has provided an idea of which UV treatment is the most effective, which will allow the creation of user guides that specify the amount of energy, suspension height and duration of application for each type of luminaire for commercial purposes.

During the study conducted on strawberry plants, the lamp model emitting at a wavelength of 275 nm and using a dose of XXX mJ/cm2 demonstrated its predominant appeal. Thanks to this treatment, the plants showed a significant reduction in the average loss of chlorophyll throughout their cultivation, compared to untreated plants or those treated with the product Armicarb®.

In detail, the treated plants lost an average of 104.215 mg/m2 less chlorophyll than the untreated plants, and a loss of 27.011 mg/m2 compared to those having received the Armicarb® treatment (p = 0.00002).

Furthermore, the different methods of UV exposure did not have a significant effect on the dry mass of the strawberry plants (p = 0.167), nor on the sugar content of the fruits (p = 0.784). Regarding the trial on Cannabis, the UV treatment that produced the highest proportion of healthy plants (without powdery mildew) is that using a wavelength of 310 nm with a dose of XXX mJ/cm2, showing a rate of 90% healthy plants (p = 0.009).

This proportion was not statistically different from that obtained with the Armicarb® treatment. Regarding mite infestations on the apical part of the plants, the treatment using a wavelength of 310 nm with a dose of XXX mJ/cm2 showed the lowest proportion of mite attacks, with 80% of the plants remaining healthy (p = 0.022).
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In contrast, the Armicarb® treatment recorded the lowest proportion of uninfected plants, with only 40% of them remaining free from attacks.

No significant variation was observed with regard to the increase in stem diameter (p = 0.598) or the evolution of chlorophyll (p = 0.059) among the various UV treatments and the positive and negative control groups in the final experiment conducted on cannabis plants, using the tested doses.
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UV radiation revealed aspects of agronomic interest, whether in terms of the fight against powdery mildew, the control of mites, the increase in chlorophyll concentration on strawberries, and the absence of stress at these specific doses.

However, it is essential to conduct additional tests in order to determine the optimality of these UV prototypes and their true advantage.