Title : Effect of growing media on pathogenicity beauveria bassiana (balsamo) vuillemin in against tribolium castaneum (tenebrionidae: Coleoptera)
Tribolium castaneum is a significant pest in wheat flour but can attack other processed food ingredients. The presence of T. castaneum causes physical and chemical changes in processed products. Physical damage in the form of color changes in processed products, while chemical damage in the form of lipase and benzoquinone enzyme activities originating from secretions T. castaneum which causes processed products to taste spicy. Alternative pest control T. castaneum In addition to the use of insecticides, biological control can also be carried out. Biological control can be carried out by using entomopathogenic fungi such as Beauveria bassiana. This study aimed to determine the differences in the virulence levels of entomopathogenic fungi B. bassiana on various growing media in controlling pests T. castaneum. Virulence test B. bassiana to T. castaneum was conducted at four levels of conidial density, namely 105, 106, 107, and 108 conidia/mL. Each treatment consisted of three replications. Observations were made on daily mortality and for interpretation of the data used probit analysis. The observation results show that the mortality of T. castaneum was highest at a conidia density of 107 reaching 44.44% on PDA media. Cumulative mortality on the 7th day after treatment significantly differed between the three media. Probit analysis shows the LC50 value from B. bassiana was 5,896 × 107 conidia/mL on PDA media and 15.19 × 106 conidia/mL on rice media. At a density of 107 conidia/mL, The LT50 values from B. bassiana on PDA media was 13,136 days while on rice and corn media it was 22, 41 days, and 98,415 days respectively. The results of this study indicate that B. bassiana has higher infectivity on PDA media against T. castaneum compared to rice and corn media.
Keywords; infectivity, conidia density, mortality, lethal concentration