福建省柳杉毛虫的发生规律及生物学特性

Occurrence regularity and biological characteristics of Dendrolimus houi in Fujian Province

对福建省柳杉及柳杉毛虫的分布调查表明,柳杉主要分布于南平、三明、宁德、福州4个地区的多个县(市),龙岩、漳州少数的县(市)呈零星分布,分布海拔介于44～1 203 m之间;柳杉毛虫也主要分布上述4个地区,海拔介于146～1 181 m之间,龙岩、漳州未见分布,具有向低海拔适宜寄主迁移并为害的风险。柳杉毛虫1年1代,高海拔地区以卵越冬,低海拔地区以卵或低龄幼虫越冬。卵期一般9月—翌年3月,较耐寒,受精卵孵化率为62%～76%,未受精卵不能孵化;幼虫期介于3月上旬—8月上旬,低龄幼虫食量小、危害较轻,高龄幼虫食量大、危害尤为严重;蛹期为7月上旬—11月中旬;成虫期8月下旬—11月下旬,羽化后即可交配、产卵,产卵期持续6.7 d,平均产卵242粒;雌虫平均寿命12.8 d,雄虫平均寿命10.3 d;雌雄性比为1∶1.22。

A survey was conducted on the distribution of cedar trees (Cryptomeria fortune) and cedar caterpillars ( Dendrolimus houi) in Fujian Province. The results showed that cedar forests were mainly distributed in many counties in Nanping, Sanming, Ningde, and Fuzhou. Sporadic distribution of cedar forests were also found in Longyan and Zhangzhou areas. The forests were found at altitudes between 44 to 1 203 meters above sea level. D.houi were also found in the above four areas at altitudes between 146 to 1 181 meters. Longyan and Zhangzhou had no distribution, and there was a little risk of migration of D.houi to lower altitude areas where preferable hosts existed. D.houi lives one generation per year, and tends to overwinter by eggs at high altitude areas, and by eggs and young larvae at low altitude areas. The eggs last from September to March of the following year, indicating that the eggs are more tolerant to cold temperatures. The hatching rate of fertilized eggs was 62%-76%, and the unfertilized eggs could not hatch. The larvae stage lasted from early March to early August, the young larvae had small amount of feeding and slight infestation, but the higher instar larvae tended to cause serious infestation due to their horrendous appetites. The pupae stage was from early July to mid-November. The adults emerged during late August to late November. Moths of D.houi mate after emergence lay eggs. The spawning period lasted about 6.7 d after mating with an average laying rate of 242 eggs. The average longevity is 12.8 d for female moth, and 10.3 d for male moth;and the sex ratio of female to male is 1∶1.22.