Wavelet analysis of the occurrence frequency of Proxenus lepigone (Moschler)

Author of the article:GUAN XiuMin1**ZHU JunSheng1CHEN ShuJuan2LIU MaiFeng3HU YingHua4LI GuoQiang5DONG BaoXin1

Author's Workplace：1. Shandong Plant Protection Station，Jinan250100, China； 2. Shandong Academy of Agricultural Sciences，Jinan250100, China；3. Feicheng Plant Protection Station，Feicheng271600, China； 4. Jining Plant Protection Station，Jining272037, China；5. Tengzhou Plant Protection Station, Tengzhou277500, China

Key Words：wavelet function, Proxenus lepigone, occurrence regularity, corn

Abstract：     Proxenus lepigone (Moschler) ( Lepidoptera: Noctuidae), a species mainly distributed in Japan, Korea, Russia and Europe, was first discovered in China in a summer maize field in Hebei Province in 2005 July. The range of P. lepigone in China has expanded in recent years, and it is causing progressively more damage. In 2011, an outbreak on the summer corn crop in China involved 302 districts, 6 provinces and 47 cities and covered an area of nearly 2 200 000 hm². P. lepigone was first found in Shandong Province on maize crops in Dezhou City in 2007, and later in 17 cities in that Province, where it caused serious damage. In order to more accurately determine the occurrence generations, development period, peak period, peak day, and so on，we analyzed trapping data on P. lepigone adults using symlets wavelet transformed filter high frequency information. The results show that P. lepigone has 4 generations a year in Shandong Province; an overwintering generation, first generation, second generation and third generation. The appearance of the first overwintering moths is from the end of March to the middle of April, overwintering generation moths occur from the end of March to the middle of April. The occurrence period of the first generation is from early April to late June, that of second generation from middle June to middle August, the third generation from early August to late September, and overwintering larvae from midSeptember to late October; after that the mature larvae overwinter in cocoons. In addition, field and laboratory observations indicate that a high temperature environment is not conducive to P. lepigone larval growth and development. Adult deformity rates are very high in July and August because of high temperature.