Attraction effect of different host-plant to Colorado potato beetle Leptinotarsa decemlineata

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is one of the most destructive pests of potato crops and has expanded its range worldwide. CPB was first discovered in the foothills of the Rocky Mountains, where it originally fed on a native species, Solanum rostratum. Its shift to the potato, Solanum tuberosum L, is an outstanding example of a native insect attaining pest status by expanding its host range to include an introduced, cultivated plant. Such adaptation has enabled this species to expand its geographic range rapidly since the mid-19th century. CPBs have repeatedly adapted to new host plants as they have expanded their distribution. The CPB feeds on plants in the Solanaceae family (Solanales, Solanaceae), including potato, tomato (Solanum lycopersicum L.), eggplant (Solanum melongena L.), and nightshade (Solanum nigrum L.). When CPB invaded China from Kazakhstan in the 1990s, it did not feed on tomato crops in this region, unlike in the United States. Whether the host-plant adaptability of CPBs has changed in the 20 years since their colonization of northwestern China is unclear, as is which host plant they currently prefer. In this study, we performed several experiments to test the reactions of CPBs to four plants; potato, eggplant, tomato and henbane (Hyoscyamus niger L.). The research was conducted at the Institute of Plant Protection, Academy of Agricultural Sciences of Xinjiang Uygur Autonomous Region, China, from June to September 2011. Our study focused on; i) examining the appeal of different host plants to CPB adults in the laboratory; ii) CPB consumption levels during different development stages, including four larval instars and adults; and iii) a field survey of host selectivity among different host plants. The results indicated that there were significant differences (P < 0.001) in attraction among the four plants. In order of appeal to CPB, they were (from highest to lowest): potato > henbane > eggplant > tomato. Significant differences (P < 0.001) also existed among the four plant species in the amount of leaf consumption by CPBs. Consumption levels were ranked as follows (from highest to lowest): potato > henbane > eggplant > tomato. In addition, different development stages of CPB usually consumed different amount of food. First and second instar larvae consumed only small amounts of food, less than 50 mm in 24 hours. The third and fourth instar larvae could consume much more leaf tissue. In 24 hours, they a