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Sudan Journal of Agricultural Research
Development of resistance to endosulfan, deltamethrin, and chlorpyrifos in
the cotton whitefly, Bemisia tabac; (Genn.), in the Sudan Gezira
Y. O. H. Assad, N. H. H. Bashir and E. M. A. Eltoum1
Abstract:
The efficacy of endosulfan, deltamethrin and chlorpyrifos on the control of
the cotton whitefly, Bemisia tabaci (Genn.) in the field, and the
susceptibility of this pest to the insecticides used in the laboratory, were
investigated during the seasons: 1988/89 and 1989/90. The laboratory tests
revealed that: (a) The endosulfan population developed high levels of
resistance, in terms of resistance ratio (RR) to deltamethrin after 3 sprays
(i.e. RR from 3.17X to 30.36X), after 4 sprays to chlorpyrifos (RR from I.S7X
to Sl.70X) and after 4 sprays to endosulfan itself (RR from 1.73X to
31.26X). (b) Resistance of deltamethrin population to endosulfan and
chlorpyrifos has risen after 3 deltamethrin sprays, e.g. endosulfan RR from
2.36X to 5.89X and chlorpyrifos from 1.92X to 6.24X and to deltamethrin
itself (from 3.42X to 14.83X). (c) The chlorpyrifos population showed high
levels of resistance to deltamethrin (i.e. RR from 2.94X to 19.03X) and
moderate levels of resistance to endosulfan (from 1.59X to 5.93X) and to
chlorpyrifos itself (from 1.79X to 7.03X) after three chlorpyrifos sprays.
Based on the logarithmic dosage probability (Ld-p) lines, all populations,
in both seasons, proved to be heterogeneous to the three chemicals.
Generally, the resistance to deltamethrin in both endosulfan and
chlorpyrifos populations was greater than to endosulfan and chlorpyrifos on
the same population.
Keywords:
Sudan Journal of Agricultural Research Vol. 2 (1999) PP. 57-63
