Biological control of postharvest tomato fruit rots using Bacillus spp. and Pseudomonas spp.

Background Postharvest diseases cause a wide loss to tomato fruits during handling and storing from harvest to consumers. Fungicides are mainly used to control postharvest diseases. Biological control is the eco-friendly substitute strategy used for postharvest diseases management as which becoming promise worldwide. Six bacterial bioagent (i.e., Bacillus subtilis, B. amyloliquefaciens, Pseudomonas resinovorans, P. alcaligenes, P. putida and P. stutzeri) were tested to suppress both Geotrichum candidum and Alternaria alternata causal agents of tomato fruit rots during storage.Results In vitro, most of bioagents significantly reduced mycelial growth rate of G. candidum. Both of B. subtilis and P. stutzeri were the most superior bacterial bioagents with values 67.03 and 72.2%, respectively. In addition, B. subtilis and B. amyloliquefaciens resulted in the most superior over all antagonists against A. alternata. The lowest percent of disease incidence and severity of G. candidum were obtained by B. subtilis and P. stutzeri. The maximum reduction percent of it on tomato fruits was recorded by applying B. subtilis and P. stutzeri with values (90 and 87%) and (91, 89%) in both seasons, respectively. Also, the highest reduction of A. alternata was obtained by using B. subtilis, which resulted in 85 and 84% in both seasons, respectively. The application of bioagents against both pathogens was significantly improved fruit quality aspects (weight loss, vitamin C, TSS and acidity %) during storage period compared to infected control fruits.Conclusion The findings revealed that both of B. subtilis and P. stutzeri could be potential biological control agents against most postharvest pathogens of tomato fruits. This might be an alternative control strategy instead of fungicides which service the sustainable and organic farming.