This study was conducted to '~vestigatc the effect of some physical and
chemicai host plant leaf proporues such as thickness and hairne ss of cuticular layer
and carbohydrates on the biology of the two tetranychid miles; Tetranychus urticoe
Koch and Eutetranychus orienta/is (Klein). Phaseo/us vulgaris L.. Gossyp < /em>usrn
barbadense L. and So/anum melon gena L. were considered 10 be the most suitable
for T. unicee as it accelerated development (9.93, 11.00 and 11.37 days), prolonged
adult female lonqevlry (18.50. 15.27 and 12.24 days) and increased its fecundity
(100.34,70.40 and 63.34 eggs). respectively. T. urticee p < /em>reference of the lower leaf
surface may be due to its very thin cuticular layer which couldn't be i-ieasured
,compared with that of the other plants (1.6~). Dense hair leaf surface was s .,table for
mite morphology due to Its narrow body and long legs and cheliceral 5tylels.
On the contrary. Citrus aurantium (Macfad) and P/umena obtusa L. were (he
most suitable hosts for E. orienta/is as it accelerated development (11.02 and 11.48
days), prolonged female longevity (15.32 and 12.00 days) and increased its fecundity
(25.40 and 22.34 eggs), respectively, Smooth leaf surface in C. auranlium and P,
oblusa as well as thick cuticle covering the upper epidermis (3.1 \J) proved to be
suitable for E. orientalls development and reproduction.