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Tuta absoluta (Meyrick) is a destructive pest of tomato crops. The cryptic nature of larvae often leads to low control efficacy. Sterile insect technique (SIT) has the potential to be an alternative management option for T. absoluta. In this study, the optimal dose for T. absoluta sterility was determined by estimating the effect of gamma radiation on parental generation (F0) and their descendants (first and second generation, F1 and F2). Adult emergence was not affected when T. absoluta pupae were exposed to gamma radiation at doses of 100~400 Gy. However, increasing doses of radiation increased deformed individuals and shortened their longevity. Furthermore, as the dose increased, F0 females showed decreased fecundity and fertility, and they were completely sterile when exposed to 300 Gy. The survival and sex ratio of females declined significantly in F1 of irradiated males with increasing doses. Moreover, we found that 300 Gy of gamma radiation did not affect the mating competitiveness of F0 males. Interestingly, this treatment caused a considerable reduction in the number of descendants and caused inherited sterility in F1 by lowering their fecundity and fertility. Therefore, the optimal radiation dose was 300 Gy, and the release of sterile adults may suppress T. absoluta population growth in the field. Our findings provide basis for controlling T. absoluta through SIT programs. [ABSTRACT FROM AUTHOR]

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is considered one of the most economically important invasive pests that causes severe damage to tomato crops. The biopesticide spinosad is widely used for controlling T. absoluta. This study aimed to investigate the spinosad-induced intergenerational sublethal effects on T. absoluta. Results showed that spinosad exhibited high toxicity against 3rd instar T. absoluta with the LC50 of 0.04 mg L-1 after 72 h exposure. The LC10 and LC30 of spinosad significantly decreased the durations of various developmental stages and some reproductive parameters of parental (F0) T. absoluta compared to control. The developmental durations, survival rate, reproduction and life table parameters (intrinsic rate of increase, r; finite rate of increase, r; net reproductive rate, R0; and oviposition days, Od) were significantly decreased in the progeny generations (F1 and F2) following F0 exposure to the LC10 and LC30 of spinosad as compared to the control group. Additionally, the mRNA expression levels of development and reproduction related genes such as Vg, VgR, and JHBP were down-regulated in parental and progeny generations at both spinosad treatments as compared to control treatment. The resistance related cytochrome P450 genes CYP321C40 and CYP6AW1, followed by CYP4M116, CYP9A307v2, CYP15C1, CYP339A1, and CYP6AB327 were up-regulated at spinosad-treated groups in the parental and progeny generations of T. absoluta as compared to control. Overall, these results showed that although spinosad exhibited high toxicity and induces intergenerational sublethal effects on the parental and progeny generations, the indiscriminate and long-term application might causes resistance development in of T. absoluta. [ABSTRACT FROM AUTHOR]

Orius predators are important natural enemies of thrips, whiteflies and mites and are reared as commercial biological agents. Due to the importance of food sources in natural-enemy mass-rearing programs, researchers have been screening efficient food sources for the rearing of such enemies. In this study, we compared the demographic fitness of Orius strigicollis reared on 3 foods (i) frozen 48h-old eggs (FE) of Spodoptera frugiperda, (ii) frozen 24h-old 2nd instar larvae (FL) of S. frugiperda, and (iii) 2nd instar larvae of Frankliniella occidentalis (western flower thrips, WFT) using the age-stage, two-sex life table. According to the life table analysis results, O. strigicollis were successfully maintained on FL for consecutive generations, and the reproductive performance of individuals from the 1st (G1) and 6th (G6) generations was evaluated. Among the 3 tested foods, FE was the lowest suitable food, leading to slower development and lower O. strigicollis fecundity than with other foods. In overall, O. strigicollis showed similar fitness when reared on WFT and on FL (no difference in fecundity), although the intrinsic rate of increase (r) and finite rate of increase (λ) was lower on FL. The fecundity and longevity of G6 O. strigicollis reared on FL were not significantly different from those of G1. The results indicate that frozen S. frugiperda larvae could be a promising factitious food for the long-term rearing of O. strigicollis and more broadly that frozen larvae of Lepidoptera may be potential new factitious food sources for Orius spp. rearing. [ABSTRACT FROM AUTHOR]