JOURNAL OF PLANT PATHOLOGY, cilt.103, sa.3, ss.751-758, 2021 (SCI-Expanded)
Chemicals used for plant health may have negative impacts on humans, animals and environment, thus antagonistic microorganisms have become popular for the control of plant diseases. Acidovorax citrulli (Ac)-induced melon bacterial fruit blotch (BFB) disease poses serious threats worldwide to the production of cucurbits, especially melon (Cucumis melo) and watermelon (Citrullus lanatus). In this study, effects of 14 different antagonistic bacteria isolated from the phyllosphere of melon and watermelon were tested against BFB through seed treatments under growth chamber conditions and through foliage sprays under greenhouse conditions. When seeds were treated with antagonistic bacteria, seven of them reduced disease incidence by over 50% and disease severity by about 70%. Then, these seven antagonists were sprayed on melon leaves twice (1 and 15 days after transplanting) under greenhouse conditions and disease development was monitored weekly for five weeks. As compared to the control, Pseudomonas oryzihabitans Antg-12, isolated from watermelon leaf, reduced both disease severity (55.85%) and the area under the disease curve (AUDPC) (66.85%), and increased yield by about 41%. In the present study it was shown that certain bacterial biocontrol agents can substantially reduce disease and, when added into integrated management of BLB, may well provide very useful solutions to disease control. To further prove this, studies using the antagonists under open field conditions are planned.