title: Influence of Landscape Diversity and Composition on the Parasitism of Cotton Bollworm Eggs in Maize.
abstract: We deployed >50,000 Helicoverpa armigera eggs in maize fields to assess the rate of parasitism by Trichogramma chilonis across 33 sites during a three-year span (2012-2014) in northern China. Subsequently, we used a partial least squares (PLS) regression approach to assess the relationship of landscape diversity with composition and parasitism potential. The parasitism rate of H. armigera eggs by T. chilonis ranged from 0-25.8%, with a mean value of 5.6%. Landscape diversity greatly enhanced parasitism at all four different spatial scales (0.5, 1.0, 1.5 and 2.0 km radius). Both the proportion of arable area and the total planting area of two major crops (cotton and maize) had a negative correlation to the parasitism rate at each scale, whereas parasitism was positively correlated to the proportion of host crops of H. armigera other than cotton and maize at the 0.5 to 2.0 km radius scales as well as to that of non-crop habitat at the 0.5 and 1.0 km radius scales. The study indicated that maintaining landscape diversity provided an important biocontrol service by limiting H. armigera through the egg parasitoid T. chilonis, whereas rapid agricultural intensification would greatly reduce the presence and parasitism of T. chilonis in China.
authors.affiliation: College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.|State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Long
authors.initials: L
authors.lastname: Yang
authors.affiliation: College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.
authors.forename: Yizhong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D044822:Biodiversity; D016018:Least-Squares Analysis; D008962:Models, Theoretical; D009036:Moths / Q000502:physiology*; D010063:Ovum / Q000502:physiology*; D010271:Parasites / Q000502:physiology*; D012044:Regression Analysis; D003313:Zea mays / Q000469:parasitology*