Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly invasive polyphagous pest that causes great economic losses to agricultural production. Emamectin benzoate (EMB) is one of the most popular biopesticides with high antipest, anti-parasitic and anti-nematode activities and low toxicity. The present study was conducted to determine the lethality of EMB to FAW for 24 h. Sublethal effects of EMB on FAW parental and offspring generations were also assessed. LC10, LC20 and LC50 EMB for 24 h on FAW third instar larvae were 0.0127 mg/L, 0.0589 mg/L, and 0.1062 mg/L, respectively. A low dose of sublethal concentrations of EMB could significantly influence the life cycle of FAW parental and offspring generations. Sublethal concentration (LC20) of EMB significantly prolonged the pupal period of male and increased the pupal weight of male but not of female, and significantly delayed the oviposition period and longevity of adult FAW. In the FAW offspring generation, sublethal concentrations significantly increased the mortality of offspring pupae and pre-adults, and reduced the development time of offspring larvae and pre-adult male and female. Sublethal concentrations (LC10 and LC20) of EMB significantly decreased the FAW oviposition period. However, only LC10 significantly reduced FAW F1 female fecundity. No significant difference was found in the intrinsic rates of natural increase (rm), finite rate of population increase (λ), and net reproductive rate (R0) of FAW offspring exposed to sublethal concentrations. This is the first study to determine the sublethal concentrations of EMB on the life table parameters of two FAW generations. These findings can provide important implications for the rational utilization of FAW insecticides.

Tea green leafhopper (Empoasca onukii Matsuda) is a critical pest in tea production. Wolbachia has attracted much attention as a new direction of pest biological control for its ability of manipulating the hosts’ reproductive biology. In this work, we focused on the detection of Wolbachia in tea green leafhopper and its effect on host reproduction and development. Polymerase chain reaction (PCR), real-time PCR, and fluorescence in situ hybridization (FISH) techniques were used to detect the distribution of Wolbachia in tea green leafhopper. Wolbachia infection levels were different in different organs of hosts in different insect stages. In addition, comparison between the infected populations and cured population (treated by tetracyclines) revealed that presence of Wolbachia apparently influenced the growth, life cycle, and other reproductive factors of tea green leafhopper, caused, for example, by cytoplasmic incompatibility (CI), thereby reducing number of offspring, shortening lifespan, and causing female-biased sex ratio. This research confirmed that the bacteria Wolbachia was of high incidence in tea leafhoppers and could significantly affect the hosts’ reproductive development and evolution.

Aleurocanthus spiniferus (Quaintance), namely tea spiny whitefly (TSW), belongs to the family Aleyrodidae in the order Homoptera, widespread in tea trees and fruit trees in many countries or regions. In this study, the preference of TSW for different colours was evaluated in tea gardens. Yellow was the colour most preferred by TSW, followed by pink, red, white and other colours. The controlling technologies about the number of sticky traps in a certain area of tea garden and the height of sticky traps above tea canopy were also evaluated, the results indicated that the attractive effect of 20 traps/667 m 2 of trials area and the height of 10 cm above tea canopy were significantly higher than others treatments. In addition, more TSW

At present, chayote (Sechium edule (Jacq.) Swartz) have been widely planted in Guizhou Province, southwestern China, and the cultivation area in Huishui county ranks first among all the counties or cities in Guizhou Province. Chayote leaf spot was firstly observed in Huishui County (25.99°N, 106.64°E) from April to June in 2019. The disease incidence ranged from 52% to 58%, and the severity of leaf symptoms ranged from 34 to 41% across nine chayote plantations. Such levels disease development lead to considerable enocomic losses. Leaf lesions initially occurred at the leaf margins, and the lesions expanded gradually, becoming dark brown and irregularly shaped. To identify the leaf spot-associated pathogen, the samples were cut from lesion margins, sterilized with 75% ethanol followed by 0.5% sodium hypochlorite for 30 s, rinsed with sterile water three times, and transferred onto potato dextrose agar (PDA). They were then incubated at 25°C in darkness for 5 days. The hyphal tips from the margins of growing colonies were successively transferred to fresh PDA plates for obtaining isolates. All strains grew with a similar morphology on PDA, malt extract agar (MEA), and oatmeal agar (OA) plates, and the colonies presented smooth margins and abundant mycelia on all three media. The colonies were gray to light green on PDA and gray on MEA and OA at 5 days post-inoculation. At 11 days post-inoculation on 10% V8 medium at 25oC with a cycle of 14 h/ultraviolet light and 10 h/night, sexual morph was observed, ascomata pseudothecioid, subglobose, 121 × 142 μm, ostiolate, walls of brown textura angularis, and smooth. Asci were bitunicate, cylindrical to clavate, 7 × 90 μm, 8-spored, ascospores elliptical, straight to slightly curved, 5 × 17 μm, 1-septate, constricted at the septum, sub-hyaline, and smooth. Conidiomata were pycnidial, subglobose, 166 × 258 μm, ostiolate, wall of dark brown to black textura angularis, smooth. Conidia were short, cylindrical or slightly reniform, 6.18 ± 0.67 × 3.51 ± 0.33 μm (n = 50), 0-1 septate, hyaline, smooth. Chlamydospores were subhyaline to dark brown, verruculose or incidentally tuberculate, and solitary or in chains, and 14.16 ± 1.23 × 5.92 ± 0.49 μm (n = 50). The morphological characteristics of the strains were identical to those of Stagonosporopsis caricae (Aveskamp et al. 2010; Sivanesan 1990). The genes or DNA sequences of the partial 28S large subunit rDNA, the internal transcribed spacer, RNA polymerase II second largest subunit, and beta-tubulin were amplified (Liu et al. 1999; Rehner and Samuels 1994; Sung et al. 2007; Vilgalys and Hester, 1990; White et al. 1990; Woudenberg et al. 2009). The sequences were further deposited in GenBank (ITS: MZ619042-MZ619044, LSU: MZ620651-MZ620653, RPB2: MZ673652-MZ673654, and TUB: MZ673649-MZ673651). A phylogenetic analysis confirmed these strains to be identical to S. caricae reference strains CBS 248.90, CBS 282.76, and PD 06/03082531. Pathogenicity tests were performed on potted chayote and five-year-old chayote in the field. Mycelial plugs (6 mm diameter) were applied on wounded chayote leaves. Brown spots appeared on the wounded sites of chayote leaves after inoculation with mycelial plugs. No symptoms were observed on the leaves inoculated with PDA plugs lacking mycelia. The re-isolated pathogen from diseased plants was identical to the representative strains used for inoculation. To our knowledge, this is the first report of S. caricae causing leaf spot on chayote in China, and our findings will be useful for its management and further research.