Peanut Root Rot (PRR) is a devastating disease that significantly limits peanut production worldwide. Although PRR has been frequently reported in Henan Province of China, the predominant Fusarium species and their sensitivity to different fungicides remain unclear. Between 2021 and 2023, we surveyed 81 peanut fields across 17 cities in Henan Province, China, to assess PRR prevalence and Fusarium species distribution. A total of 1131 Fusarium isolates were identified based on the morphological characters and phylogenetic analyses and classified into 11 recognized Fusarium species: F. solani (56.06%), F. oxysporum (20.87%), F. neocosmosporiellum (13.62%), F. proliferatum (4.69%), F. acuminatum (1.33%), F. commune (1.15%), F. graminearum (1.06%), F. pseudograminearum (0.35%), F. ipomoeae (0.35%), F. lacertarum (0.26%), and F. armeniacum (0.26%). Pathogenicity assessments showed that all 11 Fusarium species were capable of causing PRR, with F. solani exhibiting the highest isolation frequency and widespread distribution in all areas. Furthermore, the four Fusarium species (F. solani, F. oxysporum, F. neocosmosporiellum, and F. proliferatum) were highly sensitive to the six fungicides, including prochloraz (EC₅₀ values of 0.02 ± 0.00~0.06 ± 0.01 mg/L), pydiflumetofen (EC₅₀ values of 0.31 ± 0.07~0.67 ± 0.06 mg/L), tetramycin (EC₅₀ values of 0.11 ± 0.02~0.58 ± 0.08 mg/L), tebuconazole (EC₅₀ values of 0.26 ± 0.07~0.65 ± 0.10 mg/L), prothioconazole (EC₅₀ values of 1.14 ± 0.16~3.15 ± 0.81 mg/L), and difenoconazole (EC₅₀ values of 0.62 ± 0.12~3.58 ± 0.76 mg/L). This comprehensive study is the first systematic documentation on the prevalence, virulence, and fungicide sensitivity of PRR pathogens in Henan Province. The findings of the current study will provide a theoretical basis for the effective management of peanut root rot in Henan, China.

Myzus persicae is a worldwide insect pest with high resistance to many traditional insecticides. Cycloxaprid, a novel cis-configuration neonicotinoid insecticide, is effective in controlling neonicotinoid-resistant insect pests. Lethal and sublethal effects of cycloxaprid on M. persicae were conducted in this study. Results showed that cycloxaprid had higher toxicity to the laboratory and field resistant M. persicae than imidacloprid. Because of the resistance, imidacloprid showed lower control efficacy (84.79%) against M. persicae in the field. In addition, in order to quantify the sublethal impacts of cycloxaprid, we conducted a life table analysis on M. persicae. When resistant M. persicae was treated with LC₂₅ of cycloxaprid or imidacloprid, the longevity and fecundity of F₁ adults were significantly decreased. Meanwhile, the intrinsic rate of increase (r_m), finite rate of increase (λ) and net reproduction rate (R_i) of F1 generation M. persicae were reduced in cycloxaprid and imidacloprid treatments. Therefore, cycloxaprid shows high potential as a candidate insecticide for managing imidacloprid-resistant M. persicae. Importantly, our laboratory data indicate that exposure to its low sublethal concentration (LC₂₅) inhibits population growth parameters, suggesting a low risk of inducing pest resurgence under such conditions.

A biopesticide from marine-derived amino-oligosaccharides (AO) are extensively utilized in China, yet there is a lack of scientific literature on their potential ecological risks when transmitted through the food chain to Neoseiulus barkeri, a natural predator of Frankliniella occidentalis. In this study, we conducted a comprehensive investigation into the food chain effects of AO on both F. occidentalis and N. barkeri. Our findings indicate that AO-treated cucumber leaves facilitated the population growth of F. occidentalis but indirectly suppressed the fecundity of N. barkeri which fed on the first instar nymphs of F. occidentalis. Besides, F. occidentalis that ingested AO-treated cucumber leaves exhibited elevated levels of total protein and defense enzymes, including catalase (CAT) and peroxidase (POD), whereas the detoxification enzymes activity, such as carboxylesterase (CarE) and cytochrome P450 monooxygenase (P450), was diminished. Conversely, N. barkeri exhibited decreased levels of the defense enzymes superoxide dismutase (SOD) and POD, coupled with an elevated CarE activity, because of AO food chain transmission. In conclusion, the food chain effects of AO on non-target organisms F. occidentalis and N. barkeri may involve the modulation of defense and detoxification enzyme activities, leading to varying fitness costs. These findings provide critical insights for agricultural pest management strategies, highlighting the necessity of evaluating the effects of AO on non-target organisms within ecosystems, especially beneficial insects, during its application.