Effects of UVA and UVB radiation on growth, development and physiological metabolism of Tuta absoluta

Objective To explore the effects of UVA and UVB radiation on growth, development, population life table parameters and antioxidant enzyme activities of Tuta absoluta, and clarify the stress effects induced by ultraviolet radiation on this pest.

Methods All developmental stages of T. absoluta were treated with UVA radiation, UVB radiation and CK (natural light control). The developmental duration, survival rate, population growth parameters and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were determined.

Results UVA and UVB radiation significantly altered the growth and development of T. absoluta. Under UVB treatment, the egg, pupal and adult developmental durations were 5.59 d, 11.58 d and 17.00 d, respectively; under UVA treatment, the corresponding durations were 5.40 d, 8.90 d and 15.30 d. The egg, pupal and adult durations of both UV treatments were significantly longer than those of the CK group, while the larval developmental duration was remarkably shortened. The UVB group had the lowest egg hatching rate, with R₀=0.26 and r_m=0.04; the UVA group had R₀=3.69 and r_m=0.05; the CK group had R₀=23.26 and r_m=0.10. The mean generation time of the UVB group (31.24 d) was significantly longer than that of the UVA group and slightly longer than that of the CK group (30.82 d). The activities of CAT and POD increased significantly under both UVA and UVB stress; SOD activity only rose significantly under UVA treatment, and there was no significant difference in SOD activity between the UVB group and the CK group.

Conclusion UVA and UVB radiation significantly prolonged the developmental durations of eggs, pupae and adults, shortened larval developmental duration and inhibited population growth of T. absoluta, and UVB exhibited stronger inhibitory effects than UVA. Under ultraviolet radiation stress, T. absoluta upregulates the activities of antioxidant enzymes to resist oxidative damage. CAT and POD are sensitive to both UVA and UVB bands, whereas SOD only produces a specific response to UVA exposure. The differential stress effects of the two UV bands clarified in this study can provide an experimental basis for developing physical green prevention and control technologies using targeted ultraviolet radiation against T. absoluta.