The potential of botanical extracts such as Celosia argenea L. (Caryophyllales: Amaranthaceae), Ricinus communis L. (Malpighiales: Euphorbiaceae), M

Tirathaba rufivena Walker (Lepidoptera: Pyralidae) is an important pest of areca palm, Areca catechu L. (Arecaceae), in China. The effects of azadirachtin on the development and mortality of T. rufivena were determined. All larval instars were susceptible to azadirachtin, but the stomach and contact toxicities diminished as the larvae matured. The LC₂₅ and LC₅₀ dosages had no effect on larval hatch when applied directly to the eggs on different days after deposition, but the LC₉₀ treatment retarded hatch from eggs treated 1 to 3 d after deposition. The tested concentrations significantly affected the survival of neonate larvae from treated eggs, especially larvae that emerged from eggs treated 3 d after deposition. Azadirachtin also prolonged larval development and duration of the pupal stage. The percentage of adult emergence decreased, and longevity of the emerged adults was shortened, following treatment. Also, egg production and viability from females treated as larvae with azadirachtin were significantly affected. Tirathaba rufivena Walker (Lepidoptera: Pyralidae) es una plaga importante de la palma areca, Areca catechu L. (Arecaceae), en China. Se determinaron los efectos de la azadiractina sobre el desarrollo y la mortalidad de T. rufivena. Todos los instares de las larvas fueron susceptibles a la azadiractina, pero la toxicidad estómacal y del contacto disminuyeron a medida que las larvas maduraron. Las dosis de CL₂₅ y CL₅₀ no tuvieron efecto en la eclosión de las larvas cuando se aplicaron directamente a los huevos en diferentes días después de la deposición, pero el tratamiento con CL₉₀ retardó la eclosión de los huevos tratados 1 a 3 días después de la deposición. Las concentraciones probadas afectaron significativamente la sobrevivencia de larvas neonatas que nacieron de huevos tratados, especialmente larvas que emergieron de huevos tratados 3 días después de la deposición. Azadirachtin también prolongó el desarrollo larval y la duración del estadio de pupa. El porcentaje de emergencia de adultos disminuyó, y la longevidad de los adultos emergidos fue mas corta, después del tratamiento. Además, la producción de huevos y la viabilidad de las hembras tratadas cuando eran larvas con azadiractina fueron significativamente afectadas.

Tirathaba rufivena Walker (Lepidoptera: Pyralidae) is a major insect pest of Arecaceae such as Areca catechu L. (areca), Cocos nucifera L. (coconut), and Elaeis guineensis Jacq. (African oil palm). The larvae feed mainly on the palm flowers, fruits, and leaves, leading to the dropping of flowers and fruits, and they have caused economic damage and crop losses. In order to provide a foundation for the forecasting and scientific management of this pest, the effect of temperature on the development time, survival, and reproduction of T. rufivena reared on A. catechu was studied at 7 constant temperatures (16, 20, 24, 28, 32, 36, and 40 °C). The lower development threshold temperature and the effective accumulated temperature for the completion of the life cycle were 13.4 °C and 1,428.6 degree-days, respectively. The highest survival rate (30.0%) occurred at 28 °C. Eggs failed to survive at 16 and 40 °C. The population trend index (I = 19.04) and net reproductive rate (R₀ = 10.40) were highest at 28 °C. The net reproductive rate (R₀ = 4.13), intrinsic rate of increase (r_m = 0.0334), and finite capacity of increase (λ = 1.0340) were lowest at 20 °C. The mean generation time (T₀ = 18.70) was shortest at 36 °C. The population doubling time (PDT = 7.77) was shortest at 28 °C. Based on these results, we concluded that temperatures from 28 to 32 °C were most suitable for the development of T. rufivena reared on A. catechu. Tirathaba rufivena Walker (Lepidoptera: Pyralidae) es una plaga importante de insectos sobre palmas (Arecaceae) como Areca catechu L. (areca), Cocos nucifera L. (coco) y Elaeis guineensis Jacq. (palma de aceite africana). Las larvas se alimentan principalmente de las flores de palma, frutos y hojas de la palma, lo que lleva a la caída de flores y frutas, y han causado daños económicos y pérdidas de cosechas. A fin de proveer una base para el pronóstico y el manejo científico de esta plaga, se estudió el efecto de la temperatura sobre el tiempo de desarrollo, sobrevivencia y reproducción de T. rufivena criada sobre Areca catechu a 7 temperaturas constantes (16, 20, 24, 28, 32, 36 y 40 °C). El umbral mas bajo de la temperatura de desarrollo y la temperatura acumulada efectiva para completar el ciclo de vida fue 13,4 °C y 1.428,57 grados-día, respectivamente. La tasa de sobrevivencia más alta (30,0%) ocurrió a los 28 °C. Los huevos no sobrevivieron a los 16 y 40 °C. El índice de tendencia poblacional (I = 19,04) y la tasa neta de reproducción (R₀ = 10,40) fueron los más altos a 28 °C. La tasa neta de reproducción (R₀ = 4,13), la tasa intrínseca de aumento (r_m = 0,0334) y la capacidad finita de aumento (λ = 1,0340) fueron las más bajas a los 20 °C. El promedio del tiempo de generación (T₀ = 18,70) fue más corto a los 36 °C. El tiempo de duplicación de la población (PDT = 7.77) fue más corto a los 28 °C. En base a estos resultados, concluimos que las temperaturas de 28 a 32 ° C fueron las más adecuadas para el desarrollo de T. rufivena.

Chelisoches morio (Fabricius) (Dermaptera:Chelisochidae) is an important predator of Tirathaba rufivena (Walker) (Lepidoptera:Pyralidae). For better use of the natural enemy, a biological study on C. morio was conducted, particularly its developmental duration, survival, fecundity and sex ratio. And the feeding capacity of C. morio against T. rufivena was also studied under laboratory conditions. The biological study on C. morio was revealed that female adults usually lay eggs in egg masses. The number of eggs per female averaged 140.17 eggs, and the incubation period was 7.50 days. The duration of nymphal development included four instars. The immature period was 83.95 days. The longevity of males and females was 58.60 and 93.55 days, respectively. The results from the study on the feeding capacity of C. morio using T. rufivena as food revealed that C. morio adults could consume 11.08, 7.87, 7.09, 6.82 and 5.89 first-to-fifth-instar T. rufivena larvae, respectively. C. morio showed a huge amount of predation on this pest at all larval stages, implying a significant potential for the use of C. morio in controlling T. rufivena.

In this study, the changes in the conventional nutrient and mineral compositions as well as the metabolomics characteristics of the red palm weevil (RPW) Rhynchophus ferrugineus Olivier (Curculionidae: Coleoptera) larvae at early (EL), middle (ML) and old (OL) developmental stages were investigated. Results showed that the EL and ML had the highest content of protein (53.87 g/100 g dw) and fat (67.95 g/100 g), respectively, and three kinds of RPW larvae were all found to be rich in unsaturated fatty acids (52.17–53.12%), potassium (5707.12–15,865.04 mg/kg) and phosphorus (2123.87–7728.31 mg/kg). In addition, their protein contained 17 amino acids with the largest proportion of glutamate. A total of 424 metabolites mainly including lipids and lipid-like molecules, organic acids and their derivatives, organic heterocycle compounds, alkaloids and their derivatives, etc. were identified in the RPW larvae. There was a significant enrichment in the ABC transport, citrate cycle (TCA cycle), aminoacyl-tRNA biosynthesis, and mTOR signaling pathways as the larvae grow according to the analysis results of the metabolic pathways of differential metabolites. The water extract of EL exhibited relatively higher hydroxyl, 2,2-diphenyl-1-pyrroline hydrochloride (DPPH) and 2,2’-azobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging ability with the EC₅₀ values of 1.12 mg/mL, 11.23 mg/mL, and 2.52 mg/mL, respectively. These results contribute to a better understanding of the compositional changes of the RPW larvae during its life cycle and provide a theoretical grounding for its deep processing and high-value utilization.

Background: The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier), is an important quarantine pest, which has caused serious economic losses in various palm species, such as coconut, oil palm and date palm. Finding effective biocontrol resources is important for the control of this pest and the protection of palm crops. Methods: A pathogenic strain HJ-01 was isolated from infected and dead pupa of Tenebrio molitor using tissue separation method. The HJ-01 strain was streak cultured and purified, and its morphological, physiological, biochemical characteristics, and 16S rDNA homology were identified after conducting a pathogenicity test on RPW larvae. Results: Strain HJ-01 exhibited remarkable pathogenicity against RPW larvae. Under the concentration of HJ-01 suspension was 1.0 × 10⁸ cfu/mL, the mortality rate of RPW reached 82.22%, and the half-lethal time (LT₅₀) was 4.72 days. RPW larvae infected with strain HJ-01 showed reduced movement, decreased appetite, and eventual death. As the treatment progresses, the larvae’s bodies turned red, became soft, and started to rot, resulting in the discharge of liquid. HJ-01 demonstrated the ability to produce scarlet pigment after 24 h of culture on a basic medium. Colonies of HJ-01 appeared convex, bright red, moist, and viscous, opaque in the center, irregular at the edges, and emitted an unpleasant odor. Under microscopic observation, the cells of HJ-01 appeared as short rod-shaped and flagellate, with a size ranging from (1.2–1.8) μm × (1.0–1.2) μm. Genomic DNA extraction was performed on the strain, and the 16S rDNA sequence was amplified, yielding a sequence length of 1445 bp. The sequence of strain HJ-01 displayed a 99.72% similarity to that of Serratia marcescens. Phylogenetic tree analysis further confirmed that strain HJ-01 belonged to S. marcescens. Therefore, the strain HJ-01 has a very good lethal effect on RPW larvae, and it may be used as an effective bacterium for the control of RPW.