제주지역에서 솔수염하늘소 성충의 우화시기 예측모형

Abstract

The Japanese pine sawyer Monochamus alternatus Hope (Coleoptera: Cerambycidae) is well known as a primary vector of the pine wood nematode Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) that causes pine wilt disease in Korea. Therefore, it is necessary to forecast the time of adult emergence of M. alternatus for effective management of its population, and aerial application of insecticides for its control. This study was conducted to investigate the characteristic and pattern of M. alternatus adult emergence on Jeju island comparing with a published forecasting model for the adult emergence, and then to provide basic information for the control of M. alternatus. The results obtained were as follows.

1. Total 2,705 M. alternatus adults were collected over 9 years, from 2006 to 2014. and collected numbers of female and male were 1,396 and 1,309, respectively. The ratio of male to female was 0.9 (1,309 males/1,396 females). 2. Although our result shows some variations in the time of adult emergence of M. alternatus depending on years, in overall, the first adult emergence begun between late May and early June and completed between late July and early August. 3. The peak time of adult emergence of M. alternatus showed some variations depending on years, and generally occurred between 170 and 190 Julian date (late June to early July). 4. Our observed data of M. alternatus emergence from 2006 to 2013 provided a good fit for the advanced mode of previous model except for data in 2009 and 2011, which is based on degree-day (DD) and consisted of advanced, regular and delayed mode. 5. The deviation between forecasted and observed date was much lower in advanced mode than in regular and delayed mode, when we compared at 25%, 50%, 75%, and 90% cumulative emergence rate in each year. 6. Residual sum of squares (RSS) of advanced mode, regular mode, and delayed mode were 1.06, 1.95 and 5.23, respectively. Thus, RSS showed much lower values in advanced mode than in regular and delayed modes, indicating better fitting ability of the advanced mode. 7. The degree-days (DDs) from September to November in 2006-2014 ranged from 341,8 to 386.1DDs (based on a lower developmental threshold temperature of 11.9℃), which was very close to the selection criterion of 379 DDs for the selection of advanced mode in the previous model. 8.For further validation of the emergence model, data sets obtained in 2014 were validated with model outputs of advanced mode, which was expected as model selection criterion. The actual emergence was located between advanced and regular mode with slightly skewed to regular mode. 9. Based on our study, we suggested an approach which can be used to determine spraying time against M. alternatus through its prediction of adult emergence using GIS technology on Jeju island.

Our results should be useful for the prevention and control of pine wilt disease and conservation of forest ecosystem, if the forecasting model would be validated and improved further using actual field data sets in wide areas.