Supplementary UV radiation on eggplants indirectly deters Bemisia tabaci settlement without altering the predatory orientation of their biological control agents Nesidiocoris tenuis and Sphaerophoria rueppellii

Abstract

Ultraviolet (UV) radiation that reaches the earth surface has increased substantially in the past decades, altering insect-plant interactions by directly affecting herbivores behavior or indirectly by modifying plant chemistry and morphogenesis. We evaluated the indirect effect of supplementary UV radiation under glasshouse conditions on Bemisia tabaci settlement, eggplant (Solanum melongena L.) production and its effects on the flight activity of Nesidiocoris tenuis and Sphaerophoria rueppellii. Eggplants were daily radiated with different supplemental UV treatments, A +/B +, A −/B + or A −/B −, during 30, 60 or 90 min for 21 days. The whitefly settlement was assessed immediately after the UV treatments or after 18 extra days on plants kept under regular glasshouse conditions with no further supplemental UV radiation. The number of whitefly settled on plants was counted after 2, 6, 24 and 48 h. Supplementary UV radiation reduced whitefly settlement for all exposure times with alterations on the morphology and increased nitrogen and amino acid content of eggplants, mainly after 90 min of UV radiation exposition. When plants were allowed to recover under regular light conditions, growth traits were similar, and whiteflies showed no preference. Fruit parameters were not negatively altered by supplementary UV radiation. Natural enemy captures per sticky trap were more abundant under A −/B + and A +/B + conditions; however, indirect host preference tests indicated no differences among treatments. In conclusion, supplementary UV radiation could be used to reduce whitefly infestation in glasshouses at the early stages of plant development without detrimental effects on crop yield or beneficial orientation.

LEDs Make It Resilient: Effects on Plant Growth and Defense

“…Most natural UV light does not penetrate the glass of greenhouses, but may be supplied by UV LEDs. Even though UV-B can be harmful to plants as a result to DNA damage and ROS production, small doses of UV-B can improve plant defense [66][67][68][69]. Multiple studies show that low doses of UV-B light increase both basal JA and SA levels as well as the basal expression level of several defense-related genes [70].…”

Syrphids in Integrated Control of Aphids

“…Experiments showed that the average number of syrphid eggs per plant and the abundance of syrphid larvae was remarkably higher under the photo selective meshes than under the standard coverage. The effect of supplementary UV radiation under glasshouse conditions was also studied, not affecting on the flight activity of adult syrphids [13], but showing that the use of these meshes, and the release of syrphid predators, are compatible strategies to be used in IPM aphid control programs.…”

Do changes in Lactuca sativa metabolic performance, induced by mycorrhizal symbionts and leaf UV-B irradiation, play a role towards tolerance to a polyphagous insect pest?

“…Application of UV-B has been observed to have a positive effect on, e.g., basil (Mosadegh et al 2018 ; Nascimento et al 2020 ), rice (Faseela and Puthur 2018 ), chili pepper (Dolzhenko et al 2010 ), mung bean (Wang et al 2017 ), and wheat (Chen et al 2019 ). Besides, UV-B radiation impacts insect-plant interactions, directly by affecting herbivore behavior or indirectly by altering plant biochemistry and morphology (Bornman et al 2019 ; Prieto-Ruiz et al 2019 ). In addition, the use of light-emitting diode (LED) illumination in the horticultural field is constantly expanding.…”