松针鞘瘿蚊在黑松冠层的空间分布特征与脱瘿节律研究

为掌握松针鞘瘿蚊Thecodiplosis japonensis幼虫在黑松冠层的分布特征和脱瘿节律,本文采用标准株调查法,调查了松针鞘瘿蚊幼虫在冠层的不同方位的虫口密度.采用陷阱法,调查了不同时期越冬幼虫的下树数量.结果表明,在黑松树冠的顶梢、上层、中层、下层,松针受害率分别为67.42％、68.59％、52.22％和...

Spatial distribution characteristic of Thecodiplosis japonensis in the canopy of Pinus thunbergii and the time rhythm of larvae disengaging from galls

In order to grasp the distribution characteristics of Thecodiplosis japonensis larvae in the canopy of Pinus thunbergii and the time rhythm that they disengage from galls, the population density of T. japonensis larvae at different positions in the canopy of P. thunbergii were investigated through the investigation of sample trees and the number of overwintering larvae in different periods was investigated by using trap method.The results showed that in the top, upper, middle and lower parts of the canopy of P. thunbergii, the damage rates of pine needles were 67.42%, 68.59%, 52.22% and 38.41% respectively, and the number of T. japonensis larvae in each shoots were 53.40, 58.17, 57.93 and 47.69 respectively. In the five directions of East, West, South, North and top, the damage rates of pine needles were 49.19%, 53.10%, 45.76%, 57.72% and 67.42% respectively, and the number of T. japonensis larvae in each shoots were 64.54, 51.92, 52.61, 53.99 and 53.40, respectively. More than 90% of all larvae leaved the galls and dropped to the soil at two peak periods, late December and early April of the following year. The results could provide reference for the prevention and control of Thecodiplosis japonensis larvae.