Narit Thaochan and Wiwat Sausa-Ard

DOI: 10.14456/sjst-psu.2017.35

pp. 325 - 334

Abstract

The indigenous entomopathogenic fungus, Metarhizium anisopliae, was isolated from soil samples and infected
insect cadavers in fruit orchards of peninsular Thailand. Sixty-four isolates of indigenous M. anisopliae were obtained from
fruit orchards in Nakhon Si Thammarat, Patthalung, and Songkhla provinces by using selective media. The soil samples from
fruit orchards of Songkhla province gave the most fungal isolates (39), while the soil samples from Patthalung and Nakhon Si
Thammarat gave 14 and 5 isolates, respectively. Six more isolates were from the infected insect cadavers, collected from the
orchards in Nakhon Si Thammarat (4) and Songkhla (2). The conidial morphologies of the isolates were divided into four
groups based on length to width (L/W) ratio: 1.69-1.96, 2.01-2.47, 2.55-2.94, and 3.14-3.16. The efficiency of isolated
M. anisopliae against adult stage Zeugodacus cucurbitae was evaluated in laboratory conditions. The fungal isolates
PSUM02, PSUM05 and PSUM08 were the most effective with complete 100% mortality of Z. cucurbitae within seven days
from inoculation. These fungi in the soils of different fruit orchards should be further assessed for their efficacies against
different insect pests. In particular, future studies should look into the three efficient isolates identified, and determine their
key differences from the other isolates representing the same habitat or geological origin.