Persian Journal of Acarology

Abstract Acalypha wilkesiana is considered a great tool for rearing Tetranychus urticae in the laboratory; it has two colors of leaves i.e., green and red. The leaf pigment content and some chemical properties were observed in this study to examine the correlation between the biology of T. urticae and the physio-biochemical features of the green and red leaves of A. wilkesiana. Results showed that T. urticae individuals achieved faster growth and a greater number of eggs deposited by females when feeding on A. wilkesiana with greener leaves, which contained higher levels of photosynthetic pigments (chlorophyll a and b, and total carotenoids). There was a significant positive correlation (P ≤ 0.05) between T. urticae female hatchability, egg deposited/female, and daily rate with contents of total carbohydrate, total carotenoids, soluble sugars, chlorophyll a, and chlorophyll b. For male biology, there was a significant positive correlation (P ≤ 0.05) between T. urticae male life span, immature stages, and life cycle with contents of total phenols, and anthocyanin. These results indicated the role of chemical components of Acalypha leaves in the biological aspects of T. urticae.

Abstract In this study, toxicity of crude leaf extract of Calotropis procera (Aiton) (Apocynaceae) was assessed against Tetranychus urticae Koch (Acari: Tetranychidae) in laboratory conditions using the spraying method. The LC₅₀ values after 24 hours of treatment were calculated as 3608.73 and 2277.02 mg/L for female and male mites respectively. These amounts after 48 hours of treatment were 2456.98 and 1671.2 mg/L. Results showed that the incubation period, total immature and life cycle durations of T. urticae were prolonged under the influence of the C. procera extract. The fecundity and hatchability percentages were significantly lower (18.2 eggs/females and 94.38%) compared to control (44.73 eggs/females and 99.47%), respectively. The reduction rate of T. urticae at different stages after 1, 3, 7, and 14 days of spraying showed that C. procera had a positive impact on mite population reduction that recorded 94.84 and 100% for females and males 14 days post-treatment. The methanolic extract of C. procera leaves was separated into 18 fractions. The 10^th fraction exhibited 67, and 73% mortality, 48 and 72 hours post-treatment, respectively. Seventeen substances were identified in this fraction by using the GC-MS. These findings suggest that the leaf extract of C. procera which contains different novel compounds has the potential to be used for controlling T. urticae in the future.