Study on the ecological characteristics and spatial pattern of Chreonoma atritarsis larvae in Camellia oleifera

  Objective   The occurrence and damage of Chreonoma atritarsis are closely related to its ecological environment factors. The ecological characteristics and spatial distribution of C. atritarsis larvae are the basis for estimating the population density and pest prediction, which can provide theoretical basis for pest ecological control.

  Method   Based on the systematic investigation on the damage of C. atritarsis larvae in the main Camellia oleifera bases in Jiangxi Province, the spatial pattern of C. atritarsis larvae was studied by using six aggregation indexes and two regression models. The relationship between the occurrence of C. atritarsis larvae and ecological factors was analyzed by using SPSS statistical software.

  Result   The results showed that the spatial distribution pattern of the larva population was uniform, and the individuals in the population were mutually exclusive. Forest canopy density and understory vegetation coverage are the two key factors affecting the pest population rate of C. oleifera. The relationship between forest canopy density and pest population rate is extremely significant negative correlation, while understory vegetation coverage and pest population rate are extremely significant positive correlation. Understory vegetation coverage, forest canopy density, forest edge, tree height and tree age were the key factors for risk assessment of C. atritarsis. At the same time, slope aspect and slope position also had different effects on the percentage of infected plants. The distribution of C. atritarsis. larvae on the branches of C. oleifera was highly selective. They preferred to choose the branches with the age of 3-6 a, diameter of 1.5-2.2 cm, angle less than 60°, and height within 40-59 cm.

  Conclusion   The results of this study enriched the research content of spatial distribution of C. atritarsis, and showed that the spatial pattern of uniform distribution of C. atritarsis larvae was the result of the joint action of biological, ecological and environmental factors. The key forest factors affecting the occurrence and damage of C. atritarsis larvae and their distribution on branches were explored, which had practical value for guiding prediction and biological control.