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The tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is an invasive and destructive pest worldwide that feeds on solanaceous plants. T. absoluta has become resistant to most insecticides in current use. Broflanilide is a novel meta-diamide insecticide, which can bind to a new site on the γ-aminobutyric acid receptor and efficiently control insect pests of the order Lepidoptera. In this study, the acute lethal effects of flubendiamide, tetraniliprole, cyantraniliprole, chlorantraniliprole and broflanilide and the sublethal effects of broflanilide on the 2nd instar larvae of T. absoluta were assessed by leaf dip method. Among the five insecticides tested, broflanilide was the most toxic to T. absoluta with a LC50 of 0.232 mg/L. The sublethal effects of broflanilide on T. absoluta were observed at LC10 (0.053 mg/L) and LC25 (0.107 mg/L) concentrations. After exposure to low lethal concentrations of broflanilide, the larval duration was significantly prolonged, whereas the pupation rate, emergence rate and fecundity of females were all significantly decreased in F0 generation. In F1 generation, broflanilide treatments resulted in a significant decrease in female fecundity. Moreover, life-table parameters of F1 generation including the mean fecundity (F), the net reproductive rate (R0), and the intrinsic rate of population increase (r) were significantly reduced, and the mean generation time (T) was increased when compared to the control. The lethal and sublethal effects of broflanilide on T. absoluta suggested that broflanilide has good potential for management of T. absoluta. [ABSTRACT FROM AUTHOR]

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries. Since its first detection in China in late 2017, this pest has been now present in nearly 20 provinces/prefectures in China and is threating tomato and other Solanaceous crops such as potato, eggplant, and tobacco. Here, we provide a timely review on the current distribution, damage, management, and research in China. A standard survey form was designed and 30 answered surveys from 25 provinces have been received. The data showed that the damage has been witnessed in most of the regions despite that the severities vary among the regions. The management is chemicalcontrol biased, and more efforts are needed to increase the adoption of non-chemical alternatives in the Integrated Pest Management packages. An Integrated Pest Management (IPM) package called "CAMEFA" was developed and demonstrated in Yunnan and Xinjiang, the two earliest regions for the invasion. Yet, the adoption by local growers is still limited. Besides T. absoluta, we suggest a multi-pest approach by combining IPM tactics coping with other major insect pests sharing the crop. Lastly, international projects are deemed to serve as key lever for promoting IPM of T. absoluta and other invasive insect pests. [ABSTRACT FROM AUTHOR]

Symbiotic microbes have evolved to become an important source of phenotypic plasticity in host insects. In aphids, facultative endosymbionts have been found capable of influencing host phenotypes, such as against natural enemies and host fitness. However, the related evidence has been mainly gathered from a few model organisms, such as the pea aphid. Here, we explored the roles of a common facultative symbiont of the genus Rickettsia in the grain aphid Sitobion avenae. We first observed that Rickettsia-infected aphids (either natural or artificial status) benefit of a higher population increase rate (nearly 1.23-fold) than the Rickettsia-free aphids from the same genetic background. While Rickettsia presence did not confer resistance against the aphid parasitoid Aphidius gifuensis, emerged wasps from Rickettsia-infected aphids had a significantly reduced weight and their sex ratio was biased toward more female wasps. These results suggest that the presence of the symbiont ameliorates the fitness of its aphid host, but impacts the growth of parasitoid offspring and the parasitoid sex-ratio in a way that could be detrimental for the aphid. This demonstrates that the presence of a facultative symbiont may lead to both positive and negative trade-offs, which may ultimately not affect the fitness of the host population as they are compensatory. [ABSTRACT FROM AUTHOR]

Aphids have intimate associations with facultative symbionts that can help their hosts against natural enemies or heat shocks. However, these partnerships with symbionts could also induce costs for the hosts. This study focused on such associations to unearth induced costs and coevolution. Our data indicated that two strains of Regiella insecticola had negative effects on aphid fecundity, developmental time of the 3rd instar nymphs, and the age at first reproduction. Subsequently, the role of the R. insecticola was examined in the aphid's resistance to a parasitoid, Aphidius gifuensis (Ashmaed), a major agent used in biological control of the grain aphid Sitobion avenae. Results revealed that a significant reduction in emergence rate of the wasp, but not the percentage of parasitism. These results provided more evidences on a hypothesis that aphid individuals hosting facultative symbionts have a fecundity cost associated with parasitoid resistances. Additional tests were conducted to determine fitness costs of harboring the symbiont on the remaining unparasitized aphid individuals, showing no difference in aphid fecundity and survival between aphids with and without the symbiont. However, when compared to the absence of the wasp, the reproduction rate of aphids showed a strong increase under the stress of the parasitism in three aphid lines, particularly in the aphids harboring R. insecticola. This may suggest a potential evolutionary direction. Overall, the study enhanced our knowledge of the role of symbionts in host and parasite coevolution and insect pest control. [ABSTRACT FROM AUTHOR]

Over the past 14 years, the chemical hybridization agent SQ-1 (CHA-SQ-1) has been widely used for inducing male sterility in wheat heterosis in China. However, any indirect effects of CHA-SQ-1 on high trophic level of food chains (e.g., wheat pests) have not been tested. Therefore, we addressed the question, under laboratory conditions, by firstly rearing the first generation of two Sitobion avenae clones on wheats sprayed with either CHA-SQ-1 or distilled water. Then, the population parameters of the corresponding offspring of the two clones, living on wheat leaves without CHA-SQ-1, were examined across two generations. The results showed that CHA-SQ-1 significantly decreased the intrinsic rate of increase (r), net reproductive rate (R0), and finite rate of increase (λ) but not the mean generation time (T) in the aphid Kunming clone. However, in the Tianjin clone, CHA-SQ-1 clearly reduced the mean generation time (T) but not the other population parameters. These results demonstrated that CHA-SQ-1 could decelerate the growth of S. avenae populations. Additionally, the interaction was significant between aphid genotype and treatment (CHA-SQ-1) on these population parameters. The study will increase the understanding of CHA-SQ-1 on the ecological safety evaluation and pest control. [ABSTRACT FROM AUTHOR]

The importance of secondary endosymbionts on the resistance to parasitoids is increasingly recognized. Compared with Hamiltonella defensa, our understanding of the role of Regiella insecticola in protecting hosts against parasitic wasps is not well documented. In this study, we conducted experiments to determine whether R. insecticola in Sitobion avenae (the English grain aphid) could confer resistance to a parasitoid, Aphelinus asychis Walker, a major natural enemy in aphid field populations. With the genetic background controlled using clones, our results showed that infected aphids were more likely to be parasitized by A. asychis. However, compared with the uninfected controls, the weight of emerged wasps within 24 hours was significantly lower from infected aphids, suggesting that R. insecticola negatively affected the growth of the developing parasitoid larvae, although no difference in emergence rate between the treatments and the control was detected. These results will help to increase understanding of the dynamics of host-parasite-symbiont interactions. [ABSTRACT FROM AUTHOR]