农田景观格局对南疆苹果园梨小食心虫成虫种群动态的影响

Effects of Agricultural Landscape on the Population Dynamic of Grapholitha molesta Adults in Apple Orchards in Southern Xinjiang

【目的】梨小食心虫(Grapholitha molesta)是南疆苹果园一种重要害虫,严重影响苹果的产量和品质。论文旨在明确农田景观配置与组成对苹果园梨小食心虫种群数量的影响,为解析南疆地区种植业结构调整下梨小食心虫的发生趋势及灾变机制并制定种群区域治理对策提供科学依据。【方法】2017—2020年,在阿克苏地区共选择50个苹果园作为试验点,利用性诱剂诱捕监测梨小食心虫成虫种群动态,并调查试验点周围2.0 km半径范围的景观格局。在此基础上,拟合0.5、1.0、1.5、2.0 km尺度下景观格局的香农多样性指数(SHDI)、周长面积比(PARA)、边缘密度(ED)以及寄主作物、其他(非寄主)作物、非作物生境在景观中的面积占比与第1、2、3代梨小食心虫成虫数量的线性混合模型,结合赤池信息准则和模型平均,分析不同景观参数对各代成虫数量的影响。【结果】研究区域中,梨小食心虫寄主作物面积占比最高(45.7%—55.0%),其次为其他作物(18.2%—21.0%)、非作物生境(13.5%—19.7%)。模型拟合的结果显示,第1代梨小食心虫成虫种群丰富度与2.0 km景观尺度下其他作物比例负相关(P=0.062)。第2代成虫种群丰富度与4个尺度下其他作物比例均呈负相关关系(0.5 km,P<0.001;1.0 km,P<0.001;1.5 km,P=0.028;2.0 km,P=0.043),与1.0、1.5 km尺度下寄主作物面积占比负相关(1.0 km,P=0.026;1.5 km,P=0.048),与0.5、1.0 km尺度下非作物生境比例负相关(0.5 km,P=0.023;1.0 km,P=0.019),与0.5、1.0 km尺度香农多样性指数(SHDI)正相关(0.5 km,P<0.001;1.0 km,P=0.005)。第3代成虫种群丰富度与0.5 km尺度下非作物生境比例负相关(0.5 km,P<0.001)。【结论】农田景观系统中寄主作物、其他作物以及非作物生境比例的增加减少了苹果园梨小食心虫的发生量,多样性的景观格局促进了梨小食心虫在苹果园中的发生。南疆地区农业种植结构的调整显著地影响了梨小食心虫的发生,提高景观范围内其他作物、非作物生境面积占比并减少寄主作物的混栽将有利于苹果园梨小食心虫的防控。

【Objective】Grapholitha molesta is an important fruit pest in apple orchards in southern Xinjiang, which seriously affects the yield and quality of apple. The influence of agricultural landscape configuration and composition on the population number of G. molesta in apple orchards was clarified to provide a theoretical basis for the rational design of agricultural landscape that reduces the harm of G. molesta under the adjustment of cropping structure in southern Xinjiang.【Method】A total of 50 apple orchards were selected as experimental sites in Aksu area from 2017 to 2020. The landscape composition within a radius of 2.0 km of each site was investigated. The insect sex pheromone traps were used to investigate the population dynamics of G. molesta adult. Regression models of Shannon diversity index(SHDI), perimeter area ratio(PARA), edge density(ED), and the area proportion of non-crop habitats, host crops and other(non-host) crops in landscapes at four scales(0.5, 1.0, 1.5 and 2.0 km) were fitted with the number of adults of the first, second and third generations in apple orchards.【Result】In the study area,the proportion of host crops was highest(45.7%-55.0%), followed by other crops(18.2%-21.0%) and non-crop habitats(13.5%-19.7%). There was a negative correlation between the abundance of the first generation adult and the proportion of other crops at 2.0 km scale(P=0.062). The abundance of the second generation was negatively correlated with other crops at four scales(0.5 km, P<0.001;1.0 km, P<0.001;1.5 km, P=0.028;2.0 km, P=0.043), negatively correlated with the proportion of host crops at 1.0 and 1.5 km scales(1.0 km, P=0.026;1.5 km, P=0.048), negatively correlated with the proportion of non-crop habitats at 0.5 and 1.0 km scales(0.5 km, P=0.023;1.0 km, P=0.019), but positively correlated with Shannon diversity index(SHDI)(0.5 km, P<0.001;1.0 km, P=0.005). The abundance of the third generation was negatively correlated with the proportion of non-crop habitats at 0.5 km scale(P<0.001).【Conclusion】Increasing the proportion of host crops, other crops,and non-crop habitats within agricultural landscape decreased the occurrence of G. molesta in apple orchards. However,landscape diversity(Shannon diversity index) promoted the population number of G. molesta. Therefore, increasing the area of the other crops and non-crop habitats coupled with no mixed planting of host crops in landscapes could be beneficial to the management of G. molesta.