不同营林措施对樟子松林赤松梢斑螟的防治效果OA

[Objective]This study aims to evaluate the control efficiencies of 14 treatment methods under four silvicultural strategies against Dioryctria sylvestrella in Pinus sylvestris var.mongolica forests,to identify an ecological,efficient,and sustainable control approach for D.sylvestrella.[Method]Four silvicultural strategies were implemented,comprising 14 treatment methods and control plots of pure Pinus sylvestris var.mongolica forests.The manual pruning strategies included:forests with one,five,and six years after pruning,as well as stands pruned in the current year that were either near or far from agricultural fields.The mixed forest strategies included:two-species mixed forests of Pinus sylvestris var.mongolica with Populus spp.,Picea spp.,Pinus koraiensis,and Caragana korshinskii,respectively,and a three-species mixed forest of Pinus sylvestris var.mongolica,Picea spp.and Pinus koraiensis.The thinning strategies included:Pinus sylvestris var.mongolica forests thinned at intensities of 10％and 20％.The strategies of different afforestation densities included two types of Pinus sylvestris var.mongolica forests with afforestation densities of 3 333 individuals/hm2 and 1 111 individuals/hm2.Each treatment method,had a corresponding control,which was a pure Pinus sylvestris var.mongolica forest without any treatment and with an afforestation density of 1 667 individuals/hm2.The number of D.sylvestrella larvae in each treated forest stand,was investigated,and its population density was counted.The control effect was analyzed,and the control effects of the four silvicultural strategies on D.sylvestrella were compared.[Result]One,five,and six years after pruning,Pinus sylvestris var.mongolica plantations demonstrated pest control efficacy ranging from 48.38％to 73.58％against D.sylvestrella.In mixed-species plantations,the following combinations showed pest control efficacies ranging from 41.72％to 77.48％:Pinus sylvestris var.mongolica mixed with Populus spp.(number ratio is 5:5),Pinus sylvestris var.mongolica mixed with Picea spp.(number ratio is 6:4),Pinus sylvestris var.mongolica mixed with Pinus koraiensis(number ratio is 6:4),and a tripartite mix of Pinus sylvestris var.mongolica,Picea spp.,and Pinus koraiensis number ratio is(number ratio is 4:3:3).Silvicultural treatments involving 10％and 20％thinning,as well as afforestation densities of 3 333 individuals/hm2 and 1 111 individuals/hm2,resulted in pest control efficacies ranging from 71.23％to 84.93％.Among these 11 silvicultural treatments,the larval population density of D.sylvestrella was significantly reduced compared to the control(P<0.05).Conversely,in the current year pruning and mixed plantations of Pinus sylvestris var.mongolica with C.korshinskii(number ratio is 5:5),pest control efficacy was significantly lower,regardless of proximity to agricultural fields.[Conclusion]The 11 silvicultural treatment methods examined demonstrated effective control of D.sylvestrella,with efficacy rates ranging from 41.72％to 84.93％.Treatments that included five and six years after pruning,mixed planting of Pinus sylvestris var.mongolica with Populus spp.,mixed planting of Pinus sylvestris var.mongolica with Pinus koraiensis,mixed planting of Pinus sylvestris var.mongolica with Picea spp.,and Pinus koraiensis,thinning at 10％and 20％,and afforestation densities of 3 333 individuals/hm2 and 1 111 individuals/hm2,all achieved control efficacies exceeding 67％.The results of this study provide a practical basis for controlling D.sylvestrella in Pinus sylvestris var.mongolica forests.However,pruning should be carried out away from agricultural fields,mixed planting of Pinus sylvestris var.mongolica and C.korshinskii(number ratio is 5:5)should be minimized,and careful species selection should be considered for mixed plantations.