Biological characteristics and life table parameters of the two-spotted spider mite Tetranychus urticae (Koch) were studied when fed on leaves of two apple cultivars (i.e. Golden and Starking dilishz) under laboratory conditions 25±1 Cº, relative hum
idity 65±5% and 16L:8D. The intrinsic rate of increase (rm) by females of T.urticae was higher on leaves of Starking dilishz apple cultivar than on leaves of Golden dilishz apple cultivar (0.30, 0.27 female/female/day) respectively, while the generation time (T) and the time required for doubling the number of community mite (DT) were lower on leaves of Starking dilishz apple cultivars than on leaves of Golden dilishz apple cultivars (13.77, 2.3 days and 14.54, 2.55 days) respectively. The duration of the stages of growth from egg to adult female on leaves of Golden dilishz apple cultivar was longer than on Starking dilishz apple cultivars, where was (13.32 ± 1.15 and 12.22 ± 1.13), respectively, The Total fecundity on Golden dilishz apple cultivar was lower than on Starking dilishz cultivar (83.11 ± 8.91, 101.62 ± 15.48 eggs/female) respectively, The adult longevity on Golden dilishz leaves was lower than on Starking dilishz cultivar (15.33 ± 1.35, 17.14 ± 1.07 days) respectively, These differences on the apple varieties may be due to the chemical content and quality of the food and nature of the host tissue plant and the specifications can affect the rate of oviposition and development. and thus the Starking dilishz apple cultivars was more suitable for the development and reproduction of T. urticae compared with the Golden dilishz apple cultivar.
In this experiment, liquid of soap at three dosages (3, 5 and 7 ml/L) and
Abamectin (12.5 ml/100L) has been used with releas of the mite predator,
Phytoseiulus persimilis for controlling the two-spotted spider mite, Tetranychus
urticae on bean pla
nts under laboratory conditions. Contact toxicity of soap
liquid and Abamectin were evaluated and classified according to IOBC.
Efficacy of soap liquid at 3 and 5 ml/L was not sufficient to repress spider mite
populations while the using of soap liquid at three concentration with
predatory mite showed supporter effect and provide satisfactory control
whereas soap liquid determined to be slightly harmful- moderately to P.
persimilis. Abamectin with predatory mite or if used only gave sufficient control
to spider mite population but without supporter effect between Abamectin and
predatory mite whereas Abamectin determined to be harmful to P. persimilis.
However, using soap at suitable dosage, with or without predatory mite, gave
encouraging results for controlling spider mites. Generally, using of soap
showed adaptation with predatory mite and proved supporter effect for
controlling the spider mites. In despite of, soap showed no phytotoxicity to host
plants but needs to be tested in greenhouse and field conditions before
application.
