H.A. TAHA R.A. SEDRAK, SAFIA T. ABDALLA* AND A.E. SHARAF*
Plant Prot. Res. Institute, Dokki, Giza , Egypt
* Field Crops Res. Inst., ARC, Giza , Egypt .

ABSTRACT

Field and laboratory studies were carried out to evaluate the relative susceptibility of 23 locally developed soybean genotypes to spider mite (Tetranychus urticae Koch) infestation. The obtained results showed that: 1) The genotypes F9H2 families 4, 20 and 29 were highly susceptible, 2) The genotype F9H2 family 21 was susceptible, 3) The genotypes F9H2 family 111, F7H family 31, F7H5 families 2, 15 and 19, F7H15 family 2 and M7 family 94 were moderately infested, 4) The resistant genotypes were: F7H5 families 9, 16, 22 and 23, F7H15 families 5 and 17, and F9H2 family 16, 5) The highly resistant genotypes were: F7H15 families 1, 10, 12 and 21 and F9H2 family 19.
Biological studies on the 23 genotypes showed that T. urticae females oviposition period and fecundity increased when they fed on susceptible genotypes.

Key Words: Spider mites, Soybean, Resistance.