Biological Control of the Northern Root-Knot Nematode, Meloidogyne hapla in the Fields of Codonopsis lanceolata

더덕(Codonopsis lanceolata) 재배지에서 당근뿌리혹선충(Meloidogyne hapla)의 생물적 방제

This study was conducted to develop optimal control tactics of the northern root-knot nematode, Meloidogyne hapla, using cultural method and biological agents ｛Bacillus thuringiensis (Bt), Paecilomyces lilacinus and plant extract (Huhjunl)｝ in the fields of Codonopsis lanceolata. Germination of C. lanceolata was susceptible to fosthiazate, but not to Bt or a plant extract. In pot assay, the inhibitory effect of two microbial agents, Bt and Paecilomyces lilacinus, on M. hapla were significant, but less than that of fosthiazate. The plant extract also had significantly inhibitory effect on M. hapla. In field assay, treatments of P lilacinus and fosthiazate resulted in maximal yields and qualities of C. lanceolata. The effect of the plant extract on the yields of C. lanceolata was also better than no treatment. The nematode-occurring condition of the fields before transplanting had significant effect on development of C. lanceolata; nematode-occurring field type gave less yields than nematode-free field type. These results suggest that a cultural control technique using paddy field, microbial pesticides using Bt or P lilacinus, and the plant extract are the promising control tactics against M. hapla in C. lanceolata fields. As a field manual to decrease economical damage of C. lanceolata due to M. hapla, this study suggests that C. lanceolata can be cultured directly in paddy field or in upland field after nematode control using microbial agents or the plant extract.

더덕(Codonopsis lanceolata) 재배지에서 당근뿌리혹선충의 환경친화적 방제법을 구명코자 방제실험을 수행한 결과 당근뿌리혹선충 방제 실험에 사용된 방제제들(Bacillus thuringiensis, Paecilomyces lilacinus, fosthiazate, 한약제 추출물) 중 더덕의 발아를 향상시키는 것을 Bt와 한약제 추출물이었고, 억제시키는 것은 fosthiazated였다. Pot에서 미생물제에 의한 당근뿌리혹선충 밀도억제 효과는 Bt와 Paecilomyces lilacinus 모두 우수하였으나 fosthiazate 보다는 떨어지는 경향이었다. 또한 한약제 추출물도 방제효과가 우수하였다. 포장실험에서도 Paecilomyces lilacinus와 fosthiazate 처리 시 수확량이 가장 많았으며 수확된 더덕의 품질도 가장 우수하였다. 한약제추출물도 무처리에 비하여 더덕의 수량 증대에 효과가 있었고, 뿌리혹선충 감염지에서 키운 더덕을 이식한 것이 비감염지에서 키워 이식한 더덕에 비하여 수량 증가율이 저조하였다.