Efficacy of Bacillus subtilis (Ehrenberg1835) Cohn1872, in suppressing Fusarium oxysporum Schlecht. emend. Snyder & Hansen, the causal agent of root rot of date palm offshoots (Phoenix dactylifera L.) in Iraq | Učinkovitost bakterije Bacillus subtilis Ehrenberg 1835) Cohn 1872 pri zatiranju glive Fusarium oxysporum Schlecht. emend. Snyder & Hansen, kot povzročiteljice koreninske gnilobe pri dateljevi palmi (Phoenix dactylifera L.) v Iraku

English. Date palm root rot disease is one of the most important diseases of date palms and offshoots. It is caused by many soil-borne pathogenic fungi. Pathogenicity assays of the isolated fungi showed that the major causative agents of root rot disease in date palm plantlets were Fusarium oxysporum Schlecht. emend. Snyder & Hansen, F. proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg S1, F. proliferatum S2, Gibberella fujikuroi (Sawada) Wollenw., and Rhizoctonia solani J.G. Kühn. The most virulent fungus was F. oxysporum with a severity index of 82.16 % of root rot, while R. solani was the least harmful with a disease severity rate of 12.42 %. In laboratory tests, Bacillus subtilis reduced the radial mycelial growth of F. oxysporum on PDA medium by 86.6 %. The application of B. subtilis in combination with F. oxysporum substantially inhibited the severity of root rot disease relative to plantlets treated with only F. oxysporum. In addition, B. subtilis application in the presence or absence of F. oxysporum improved the plant physiology of plantlets, including total chlorophyll, total carotenoid, antioxidant enzyme levels (catalase and peroxidase), and total proline content.

Slovenian. Koreninska gniloba je najpomembnejša bolezen dateljeve palme. Povzročajo jo številne talne patogene glive. Preiskus patogenosti z izolati gliv na sadikah dateljeve palme je pokazal, da so bili glavni povzročitelji njene koreninske gnilobe naslednje glive: Fusarium oxysporum Schlecht. emend. Snyder & Hansen, F. proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg S1, F. proliferatum S2, Gibberella fujikuroi (Sawada) Wollenw., and Rhizoctonia solani J.G. Kühn. Najbolj virulentna je bila gliva F. oxysporum, z indeksom virulentnosti 82,16 % med tem, ko je bila gliva R. solani najmanj škodljiva z indeksom povzročitve koreninske gnilobe 12,42 %. V laboratorijskem poskusu je bakterija B. subtilis na PDA gojišču zmanjšala radialno rast micelija glive F. oxysporum za 86,6 %. Uporaba bakterije B. subtilis je v kombinaciji z glivo F. oxysporum znatno zavrla razvoj koreninske gnilobe na sadikah dateljeve palme v primerjavi s sadikami, ki so bile tretirane samo z glivo. Dodatno je uporaba bakterije B. subtilis v prisotnosti ali odsotnosti glive F. oxysporum izboljšala fiziološke parametre sadik kot so vsebnost celokupnega klorofila in karotenoidov, aktivnost antioksidacijskih encimov katalaze in peroksidaze ter vsebnost celokupnega prolina.