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Cotton is one of the most widely used industrial products in various industries and is attacked every year by the cotton bollworms, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae). In this study, we investigated the effect of the spinosad insecticide on some biological and bio chemical parameters of the cotton bollworm. Bioassays were performed by using 3rd instar larvae fed with artificial diets containing lethal (LC50), and sublethal (LC15) concentrations of spinosad. Lethal and sublethal concentrations were estimated to be 0.90 and 0.35, mg a.i./kg, respectively. Compared to the control, lethal and sublethal concentrations of spinosad significantly increased larval and pupal development time, decreasing their weight. In addition, only LC50 of spinosad significantly reduced the fecundity and lifespan of adults as well as the hatching rate of the pest compared to LC15 and control. Moreover, lethal and sublethal concentrations of spinosad reduced carbohydrate and glycogen content and did not change lipid content. A significant decrease in protein content was observed only after exposure to LC50. At LC50 the activities of glutathione S-tran sferase (GSTs), a- an d ß- esterase were significantly reduced compared to LC15 and control. The results of this study showed that LC50 and LC15 of spinosad affect several biochemical and biological parameters of H. armigera. Therefore, spinosad at the lethal and sublethal concentrations can be included in integrated pest management (IPM) for this pest. [ABSTRACT FROM AUTHOR]

The insecticidal and repellent activities of methanolic extracts of Ruta chalepensis L. (Rutaceae: Sapindales), Rhazya stricta Decne (Apocynaceae: Gentianales), Heliotropium bacciferum Forssk (Boraginales: Boraginaceae), Salvadora pérsica L. (Salvadoraceae: Brassicales), and Moringa oleífera L. (Moringaceae: Brassicales) were investigated against the saw-toothed grain beetle Oryzaephilus surinamensis L. (Coleóptera: Silvanidae). Results demonstrated that all these plant extracts had variable toxicity against the beetle. The effectiveness of the tested plant extracts was shown by increasing the used concentrations. The methanolic extract from R. stricta performed the best and was able to cause 93.3% and 89.2% mortality for the adult and larval stage of O. surinamensis, respectively, at 500 ppm after six days of plant extract treatment. The tested extract of S. pérsica at 500 ppm caused 80.8% and 82.5% mortality on larvae and adults of O. surinamensis after six-day of treatment. On the other hand, repellent effects of extracts of R. stricta, S. pérsica, and R. chalepensis at 500 ppm were recorded, with higher values of 91.7%, 83.3%, and 78%, respectively, against the adults of O. surinamensis, which were under 500 ppm. These extracts especially from R. stricta, S, spinosa, and R. chalepensis could be useful to prevent damages and store grain production losses for O, surinamensis. [ABSTRACT FROM AUTHOR]

The red palm mite Raoiella indica Hirst has recently invaded the Neotropical region, which demands the implementation of pest management strategies. In this study, toxicity of leaf extracts of Mexican oregano Lippia berlandieri Schauer, neem Azadirachta indica A. Juss, Mexican mint Plectranthus amboinicus (Lour.) Spreng., rue Ruta graveolens L. and Persian lime Citrus x latifolia Tanaka against R. indica was evaluated under laboratory conditions. Raoiella indica females were exposed to each plant extract at concentrations of 0.25, 0.50, 0.75 and 1% (v/v) to assess the cumulative mortality at 24, 48 and 72 h after exposure. Mortality rates of R. indica rose due to increased extract concentration and exposure time. The strongest acaricidal activity was observed with L. berlandieri, A. indica and P. amboinicus, whose 1% concentration and 72 h exposure caused a mean R. indica mortality of 100, 90 and 78%, respectively. These plant extracts hold promise for the chemical management of this pest. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the toxicity of aqueous, ethanolic and acetonic extracts of Lantana camara L. (Verbenaceae), Ruta chalepensis L. (Rutaceae) and Rhazya stricta Decne (Apocynaceae), against larvae of Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), feeding on wheat seeds after 2, 4, and 6 days (d). These plants commonly grow in arid and semi-arid conditions and may provide novel natural insecticides against larvae of T. granarium. Results showed that the plant extracts demonstrated varying levels of toxicities, with the acetonic extracts providing the greatest efficacy. The acetonic extract of L. camara demonstrated a higher toxicity effect, with LC50 of 330.6 ppm (after 2-d) and 110 ppm (6-d), compared to 467 ppm (2-d) and 251 ppm (6-d) for R. stricta, and 576 ppm (2-d) and 317 ppm (6-d) for R. chalepensis. Overall, toxicity of acetonic extracts was about 1.3 fold greater compared with that of aqueous or ethanolic extracts throughout the range of concentrations tested (50-400 ppm). The acetonic extracts required six days to achieve = 80% mortality of larvae. In conclusion, this study suggests that the acetonic extract of L. camara, R. chalepensis and R. stricta could be used as a sustainable method for controlling Khapra beetle, pest of stored grains. [ABSTRACT FROM AUTHOR]