Influence of host plant changing on the development of Tetranychus urticasKoch (Acari, Tetranychidae): consequence of mite infestation in Citrus fields.

Changes of hosts in T. urticae is associated with notorious lost of reprodu ction potentialities. At 25 degrees C, the fecundity of females which are a lways reared on Solanum nigram (75.7 eggs) fell to 1.07 eggs when they were reared on Citrus. It is the same for the longevity of females in this mite . The females permanently feeding on Citrus have a longevity of 16.9 days c ompared with only 9 days in females from Solanum nigrum that were transferr ed to Citrus. Similar changes operated at 20 degrees C produce the same res ults. The practical consequences of these experiences on the swarming of mi tes in the held of Cirtrus were analysed.