An orthogonal analysis of factors affecting the reproduction of Plutella xylostella (L.)
Author of the article:LI Xiang-Yong** YIN Yan-Qiong ZHAO Xue-Qing CHEN Ai-Dong***
Author's Workplace:(Institute of Agricultural Resources and Environment, Yunnan Academy of Agricultural Sciences, Kunming 650205, China
Key Words:diamondback moth, orthogonal experiment, host plant, population number, growth period
Abstract: [Objectives] To determine the effects of host plant species and adult density on the reproduction of the diamondback moth (Plutella xylostella). [Methods] We used an orthogonal experiment to analyze the effects of adult density, host plant, and plant developmental stage, on the F1 generation proliferation rate of the P. xylostella. [Results] (ⅰ) Adult density and host plant had very significant effects on the proliferation rate of P. xylostella (P<0.01), whereas host-plant developmental stage had a less significant effect (P<0.05). These most important factors affecting diamondback moth productivity can be ranked in descending order of importance as follows; temperature (F=24.11,P=0.001) > host (F=14.21,P=0.004) > humidity (F=7.40,P=0.019). (ⅱ) A single factor paired comparison revealed an extremely significant difference in adult productivity between 1 pair/plant and 3 pair/plant or 4 pair/plant, and between 2 pair/plant, 3 pair/plant and 4 pair/plant (P<0.01), and a less significant difference between 1 pair/plant and 2 pair/plant (P<0.05). With respect to host plant species, there was also an extremely significant difference among cabbage (Brassica oleracea var. capitata), chinese cabbage (B. rapa pekinensis), flowering chinese cabbage (B. campestris ssp. chinensis var. utilis) and cauliflower (B. oleracea var. botrytis) (P<0.01), but no significant difference among chinese cabbage, flowering chinese cabbage and cauliflower (P>0.05). With respect to plant development stage, there was an extremely significant difference between the 6-leaf stage and the 10-leaf stage (P<0.01), a less significant difference between the 6-leaf stage and the 4-leaf and 8-leaf stages (P<0.05); but no significant difference among the 4-leaf, 8-leaf, and 10-leaf stages (P>0.05). [Conclusion] Optimal conditions for diamondback moth reproduction are a combination of an adult density of 1 pair/plant, and cabbage host-plants at the 6-leaf stage of development.