Biological control of the semi-parasitic plant Loranthus grewinkii using bacterial agents Brenneria quercina, Pectobacterium atrosepticum and Dickeya chrysanthemiin various geographical directions of forests of Ilam (Gachanarea)

摘要

Aim. Semi-parasitic plants absorb water and minerals from the host plant and physiologically render it weak and eventually cause its death. Today, biological control has been considered by specialists because of environmental damages related to the use of chemical pesticides. Methods. In March 12, 2009, in the forest region of llam, several bacterial species including Brenneria quercina, Pectobacterium atrosepticum and Dickeya chrysanthemi were isolated from the host plant, Loranthus spp., to control the semi-parasitic plant biologically and to evaluate the effect of biocontrol and geographical direct on turnover of control of Loran-thus. At first, suspensions were prepared from the isolates through the Savuchok's method and a concentration of 108 cells/mL (isolates 1 and 2 relating to species Brenneria quercina, isolates 3 and 4 to the species Pectobacterium atrosepticum and isolates No. 5 relating to Dickeyachrysanthemi). Then, the isolates were inoculated during the morning. The present study was performed using completely randomized design, five treatments and six replicates at the flowering season. The data collected were analyzed using SPSS software and Duncan test. Results. Results indicated that there were significant differences among treatments in term of the amount of leaf dryness. Isolates 3 and 4 in all directions caused the most leaf dryness. Conclusion. The highest percentage of leaf dryness of the host tree was observed in the North West, while in the North the percentage was the lowest. It was detected that the bacterial agents have different impact on semi-parasitic plants in different environmental conditions.