CHEMICAL RESPONSES OF JUJUBE TREE, ZIZIPHUS SPP. TO FLAT-HEADED BORERS CHRYSOBOTHRIS. AFFINIS (FABRICIUS, 1794) INFESTATION

Jujube trees are infested by flat-headed borers (Chrysobothris affinis (Fabricius, 1974) (Coleoptera, Buprestidae) in Province of Basra; the result of the field survey during the growing season of 2021/2022 indicated that the highest infestation of flat-headed borers was on the cv. Tuffahi, with an average rate of 61.06%, followed the Bambawi and Ziatooni cultivars, reaching 18.51 and 18.45%, respectively. While, the lowest infestation was 9.95% on cultivar Wild. However, the highest infestation rates of the borers were recorded at in Zubair and Safwan regions; while the lowest infestation were at Madinah and Imam Al-Sadiq regions. The susceptibility of cultivars to infestation of flat-headed borers was studied through the chemical analysis of phenols in the trunks of different jujube cultivars. The study showed the presence of 15 phenolic compounds in the trunks of the different cultivars; there is negative relationship (r = -0.97 and -0.93) between the infestation rate and the concentration of rutin and gallic compounds. In order to figure out the reason for the occurrence of the infestation in the old branches (two years and above) compared to the young branches, which are not infested with the borers; the moisture content in the branches was studied, and an negative relationship was found between the moisture content and the insect infestation rate; high moisture content was found in the young branches, which reached 52.59% compared to the two-year-old branches that contained 30.90% moisture. The infestation flat-headed borers reduced the percentage of proteins, carbohydrates and the content of chlorophyll in the leaves of the infested trees; their averages were 15.09, 58.32% and 1.82 g/100 gm in leaves, respectively, compared to 18.92 and 71.78%, 4.22 g/100 g. in the non-infested trees; While the study indicated an increase of the concentration of phenols in leaves of infested trees, with an average of 9.78%, compared to leaves in healthy trees, which averaged 9.45% of phenols. Finally, Jujube trees have a set of integrated defense systems against pests that attack the bark and wood that may be one of the IPM elements preventing borers infestation on Jujube plantation.