UTILIZATION OF BIOLOGICAL CONTROL AGENTS FOR THE MANAGEMENT

OF POSTHARVEST PATHOGENS OF TOMATO

 

MUHAMMAD USMAN GHAZANFAR¹*, MUZAMMIL HUSSAIN^1,3,

MUHAMMAD IMRAN HAMID^1,3 AND SAMI ULLAH ANSARI²

 

¹Department of Plant Pathology, University College of Agriculture, University of Sargodha, 40100 Sargodha, Pakistan and Biosafety Laboratory, Reckenholzstrasse 191, CH-8046 Zürich, Switzerland

²Department of Applied Statistics, University College of Agriculture, University of Sargodha, 40100 Sargodha, Pakistan

³State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China

*Corresponding author e-mail: usmanghazanfar1972@gmail.com

 

Abstract

 

Twenty five isolates of Trichoderma, Bacillus and Pseudomonas spp. were obtained from rhizosphere of tomato growing fields using soil dilution technique on potato dextrose agar (PDA) and nutrient agar (NA) medium. Screening of these isolates were done against Geotrichum candidum, Trichothecium roseum and Rhizopus oryzae, causal agents of sour rot, pink mold rot and Rhizopus soft rot of tomato under the laboratory conditions. One promising isolate of each Trichoderma harzianum, Bacillus spp. and Pseudomonas fluorescens from the twenty five isolates were chosen and further evaluated as potential biological control agents (BCAs) against three important postharvest pathogens of tomato. Dual culture and spore concentration assay revealed that all three isolates inhibited radial growth of G. candidum, T. roseum and R. oryzae. Tomato fruits were inoculated with 25µl suspension of l0⁸ cfu mL^-1 for T. harzianum and l0⁸cfu mL^-1for each Bacillus sp. and P.fluorescens. Twenty four hours later the treated fruits were inoculated with 25µl of 10⁵ conidia/mL of each of three postharvest pathogens. The results showed that P. fluorescens provided good control (78.1%) of G. candidum and (82.2%) R. oryzae, while, T. harzianum proved less effective to control all three pathogens. Bacillus spp. was only effective (88.4%) against T. roseum. Hence, our results depicted that Bacillus spp. and P. fluorescens proved to be a potential antagonist of T. roseum and R. oryzae however, all the tested BCAs were not consistent in their action against three postharvest pathogens of tomato.

 

Key words: Biological control agents (BCAs), Pink mold rot, Sour rot, Rhizopus rot, Tomato, Postharvest management.