Location: Crop Bioprotection ResearchTitle: Infection of Helicoverpa armigera by endophytic Beauveria bassiana colonizing tomato plants Author
|Qayyum, Mirza - University Of Agriculture - Pakistan|
|Wakil, Waqas - University Of Agriculture - Pakistan|
|Arif, Muhammad - University Of Agriculture - Pakistan|
|Sahi, Shahbaz - University Of Agriculture - Pakistan|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2015
Publication Date: 7/1/2015
Citation: Qayyum, M.A., Wakil, W., Arif, M.J., Sahi, S.T., Dunlap, C.A. 2015. Infection of Helicoverpa armigera by endophytic Beauveria bassiana colonizing tomato plants. Biological Control. 90:200-207.
Interpretive Summary: The discovery and characterization of biological control bacteria with insect-killing properties is an efficient means to improve agriculture. We discovered a new strain of insect killing fungus from a wild tomato plant in Pakistan. The fungus is capable of growing inside of a tomato plant without detrimental effects. This study evaluated different methods of inoculating tomato plants so the fungus could become established with them. The fungus colonized plants were then shown to have insecticidal activity against tomato fruit worms. This research benefits agriculture producers and consumers by developing a new method of controlling insects.
Technical Abstract: A novel endophytic strain of Beauveria bassiana was isolated from leaf tissue of a wild tomato plant. This strain and two B. bassiana strains previously isolated from soil were evaluated for their ability to endophytically colonize tomatoes and subsequent in planta efficacy against Helicoverpa armigera larvae. The three strains were inoculated to tomato plants using root dip, injection, solid substrate and direct foliar application methods. All three strains were able to establish endophytic populations as confirmed by reisolating the fungi from leaf samples. A detached leaf assay was used to evaluate pathogencity of inoculated plants against second and fourth instar larvae at one, three and five weeks post plant inoculation. The native endophyte strain showed highest success colonizing the plants. Of the inoculation methods, root dipping was the most successful method. Larval mortality of H. armigera was significantly affected by the stage of larvae and the application method used to establish the fungus. Second instar larvae were found more susceptible than fourth instar at each interval tested. The native endophyte isolate was the most pathogenic and had the highest mortality. Pupation and adult emergence were inversely related to the establishment of the fungus. No adverse growth effects on the tomato plants were observed as a consequence of endophytic inoculation of B. bassiana, although the response was related to application method and fungal isolates. These findings suggest that endophytic colonization of B. bassiana may be an effective strategy to control H. armigera in tomatoes.