UTILIZING EUSEIUS SCUTALIS (ATHIAS - HENRIOT) TO CONTROL EUTETRANYCHUS ORIENT ALIS (KLEIN) ON CITRUS TREES

Experiments were carried out under field conditions to estimate the effect of the predatory mite, Euseius scutalis (A-H.) against citrus brown mite, Eutetranychus orientalis (Klein) on citrus trees at El-Ismailia Governorate. The predatory mite E.scutalis was released on January 9, 1992 at 40-70 adult females per tree (according to the size of the tree) when infestation level of the prey citrus brown mite E.orientalis reached 4.2 per leaf of citrus. The percentage reduction of prey popula­tion density was 82.88 after 12 months of release, then decreased to 52.46% after 21 months. So, it was felt necessary to carry out the sec­ond release of E.scutalis on November 25, 1993 when the infestation with moving stages of E.orientalis reached 4.9 individuals per leaf. The reduction percentage of E.orientalis after 13 months from the second release of the predatory mite was 70.19%. To serve the biological con­trol programme, the side effect of three organophosphorus insecticides, two nematicides, six fungicides, two herbicides and neem wp were test­ed against the predator adult females under laboratory conditions. The side effect of 9 acaricides and some mineral oils were also tested agai­nst the predator motile stages under field conditions. All fungicides test­ed, neem wp, three acaricides (Vertimec, Cascade and Ortes) and miner­al oils were harmless to the predatory mite, Escutalls. Thus, it is advisable to use these compounds in the programme of biological con­trol.