Study on alternaria alternate, fusarium chlamydosporum accompanying the eucalyptus camaldulensis L. trees in some regions of Kerbala province /Iraq and identification of isolate with PCR technique

Abstract

The aims of this study investigated the reason of eucalyptus tree decline in some reigns of Kerbala province and some methods of control .Field survey showed that all eucalyptus tree were decline in different degree Results of the isolation showed the presence of Alternaria alternate, Fusarium chlamydosporum on the (PDA) potato dextrose Agar.The pathogenicity test result showed the ability of fungus to cause decline on the seedlings to Eucalyptus camaldulensis L. after two months from inoculation time, the result also showed that Al. alternate was more affected with the pathogenicity which differed significantly from the fungus F.chlamydosprium where the lesion length was 2.93 and 1.84 cm respectively and significant difference from the comparison treatment. These fungi showed toxicity for Eucalyptus camaldulensis L. through new branches wilt test, and it was found that the tested fungi caused a significant loss in the amount of total chlorophyll(0.13, mg-1 wet weight), which increased by increasing concentration.The results of the Salicylic acid test with three concentrations (0, 500, 1000, mg L-1) and Beltanol with (0, 0.5, 1mg L-1) concentrations showed an active role in the inhibition process,with superiority of 1000 and 1.0 mg. L-1 concentration which recorded a 100% rate of tested fungi. The results of the effect of the Salicylic acid (1000, mg L-1) and Beltanol(1mg L-1) had an effect in reducing the length of canker lesions on Eucalyptus seedlings tested.