Influence of foliar sprays with Copper and Zinc on the resistance of citrus rootstocks to gumosis caused by Phytophthora citropthora.

Abstract

This study was conducted in the lath house, Department of Horticulture, College of Agriculture, University of Baghdad in the growing season of 2004. Sour orange, mandarin and grapefruit rootstocks with 6 months old were foliar sprayed with CuSO4. H2O at a rate of 1 gm/ l water and ZnSO4. H2O at a rate of 2 gm/ L water while the control treatment was sprayed with distilled water . After two weeks from the spraying half the number of the seedling were inoculated with Phytophthora citrophthora to investigated the influence of these chemicals in controlling the gummosis on the different rootstocks.البحث مستل من رسالة ماجستير للباحث الثانيThe experimental results shows that spraying with Zn to inoculated seedlings reduced the percentage of disease index, seedling death and seedling wilting and the rate of wilting by (34.68%, 40.73%, 34.91% and 22.39%) respectively as compared with inoculated seedlings with the fungi. Spraying with Cu to the inoculated seedling significantly reduced the percentage of disease index and seedling death, seedling wilting and the average wilting rate at ratio of 49.95%, 51.84%, 33.33% and 14.21% respectively.