This study was conducted to elucidate the genetic relationships among native Korean cattle breeds by analyzing genetic variations and distances. Relationships among Hanwoo, Korean brindle, Korean black, Jeju black, and Holstein cattle were evaluated using 15 microsatellite markers. Korean brindle and Korean black cattle had the closest relationship based on the lowest genetic distance being observed between these breeds. A Neighbor-Net tree created using the Reynolds distances indicated that Korean brindle and black cattle formed a group separate from the Hanwoo population. However, an Fst pairwise test revealed that Hanwoo, Korean brindle, and Korean black cattle differed significantly (P <0.01). Moreover, the results of this study confirmed that Jeju black cattle became a separate established breed in Korea through a path different from that of cattle from inland regions, even though it is considered to be a Korean native breed. Overall, the results of our study indicate that Korean brindle and black cattle are indeed native Korean breeds that maintain an endangered status.
Three formula types (gel, cookie, and liquid), six commercial roach bait products containing one of active ingredients among Fipronil, Avermectin, Dinotefuran, and Chlorpyrifos were examined against susceptible strain of German cockroach, Blattella germanica (L.). For the results of killing speed (LT50 values), universal killing speed effects depended on bait formula types. The killing speed of liquid bait formula type was the fastest among three formula types. Followed by gel bait type and cookie bait type. However the control speed (LT90 values) effects depended on the active ingredients that contained in roach baits. The baits contained Fipronil were shown the strongest control performance against German cockroaches. Chlorpyrifos was similar with Fipronil. Followed by Avermectin and Dinotefuran.
Entomopathogenic fungi have been studied to develop for biological control agents as an alternative to chemical control agents in insect pest management. Two Lepidopteran insects, Spodoptera exigua and Plutella xylostella, are serious insect pests infest various crops, but not effectively controlled by commercial chemical pesticides due to its high insecticide resistance. A fungal isolate was isolated from S. exigua larvae collected from green onion field in Andong, Korea. To identify the fungal isolate, 18srRNA sequence for internal transcribed spacer (ITS) and β-tubulin regions were sequenced. The ITS and β-tubulin sequence were highly matched to Beauveria bassiana and morphological characteristics also was fit to known B. bassiana. Finally, isolated fungus has identified as B. bassiana and named B. bassiana ANU1. The result of bioassay, median lethal concentrations were 2.7×103 and 0.9×103 conidia/ml and medial lethal times were 65.6 and 60.8 h to S. exigua and P. xylostella, respectively. B. bassiana ANU1 showed high pathogenicity to two insect pests from 20℃ to 30℃ at 50% relative humidity (RH) and more than 40% RH at 25℃ with 107 conidia/ml of concentration.