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Mohammadi P., Tozlu E., Kotan R., Kotan Şenol M. (2017): Potential of some bacteria for biological control of postharvest citrus green mould caused by Penicillium digitatum. Plant Protect. Sci., 53: 134-143.Ten bacteria isolate (4 Bacillus subtilis, 2 Bacillus pumilus, 2 Bacillus cereus, 1 Bacillus megaterium, and 1 agrobacterium radiobacter) were tested in vitro for antagonistic properties against Penicillium digitatum, the causal agent of citrus green mould. The effect of these bacteria was also observed on mycelial growth, spore germination, and spore production of the pathogenic fungus in broth culture. Extracellular enzyme activities of the bacteria were determined. According to the results of in vitro antagonistic tests and enzymes activities, the most promising bacteria were Bacillus subtilis and agrobacterium radiobacter. These bacteria were tested for disease suppression on lemon fruits. In addition, these bacterial isolates also showed remarkable antifungal activity against the pathogen on lemon fruits. The results of this study showed that Bacillus subtilis and agrobacterium radiobacter showed remarkable antifungal activity against the pathogen. Chitinase and glucanase enzyme activity of all the tested bacteria was positive. Protease enzyme activity was positive in all tested bacteria with the exception of agrobacterium radiobacter. In addition, all bacteria inhibited mycelial growth and spore germination (except agrobacterium radiobacter) of the fungus. Bacillus subtilis, Bacillus cereus, and agrobacterium radiobacter inhibited spore production in broth culture. Bacillus subtilis and agrobacterium radiobacter were tested on lemon fruits significantly reduced disease severity. Consequently, these isolates can be used as new biocontrol agents in controlling the post-harvest decay of citrus fruits caused by Penicillium digitatum.

The brown marmorated stink bug, Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae), is an invasive harmful pest species due to its economic losses. Its wide host range and continuous movement make its control difficult with insecticides. Biological control has recently gained importance due to the negative aspects of chemical control. The study evaluated the biological control tools by testing the entomopathogens against the pest by 11 bacteria strains and 1 fungal isolate. Brevibacillus, Bacillus, Pantoea, Vibrio, Pseudomonas, and Beauveria were tested against the nymphs of H. halys under controlled conditions. All applied entomopathogens had potentials for controlling H. halys. Mortality rates of 75 and 100% were obtained by the bacteria strains and 76.19% by the fungus, B. bassiana. Successfully reaching a 100% control rate, the bacterial isolates of the Bacillus cereus GC subgroup B and Pantoea agglomerans GC subgroup were recorded to have a greater potential than the others.

Alternaria alternata (Fr.) Keissl. which has a wide host range is an important fungal pathogen causing losses in yield in agricultural crops. The chemicals used for controlling this disease are directly toxic to beneficial microorganisms in soil. This study was carried out to determine the antifungal activities of a total 13 candidate bioagent bacterial isolates of Bacillus subtilis (TV-6F, TV-12H, TV-17C and TV 125 A), Bacillus megaterium (TV 87 A and TV 91 C), Bacillus pumilus (TV 67 C), Paenibacillus polymyxa (TV 12E), Pantoea agglomerans (RK 92 and BRT-B), Pseudomonas fluorescens Biotip F (FDG 37), Bacillus thuringiensis subsp. kurstakii (BAB-410) and Bacillus sphaericus GC subgroup D (FD 49) and bioagent fungal isolates of Trichoderma harzianum (ET 4 and ET 14) against two isolates of A. alternata isolated from strawberry and cucumber on petri plate assays. B. pumilus TV 67C (87.63%-65.89%), B. subtilis TV 6F (77.61%-63.11%) and B. megaterium TV 87A (72.93%-68.87%) bacterial isolates were the most effective isolates against pathogenic fungi in in vitro and bioagent fungal isolates ET 4 and ET 14 inhibited pathogenic fungi grown in in vitro respectively 73.87% -83.33% and 55.85% -74.44%, too. Our results indicated that B. subtilis, B. pumilus, B. megaterium and T. harzianum should be tested against A. alternata in field condition.