美洲棘蓟马对不同蔬菜寄主的偏好性

比较了美洲棘蓟马对12种不同蔬菜和1种非蔬菜的偏好性,并通过对数线性模型和方差分析对结果进行了分析.结果显示美洲棘蓟马成虫对13种寄主植物的寄主偏好性及产卵选择性具有显著差异.该虫成虫在南瓜上分布最多,平均每株寄主植物达到23.5头,在油菜上的产卵量最大,每株达50.3粒.黄瓜、南瓜、油菜、黄豆和辣椒上成虫分布量每株均在10头以上,显著多于其他寄主；而上述5种寄主上的每株产卵量也均在30粒以上,显著多于除豆角以外的其它寄主.该虫在黄瓜上发育最快,15d左右即可完成其整个未成熟期；在辣椒上未成熟期存活率最高,为80.1％.上述结果将为该虫入侵风险的评估提供重要依据.

Hosts preference of Echinothrips americanus Morgan for different vegetables

Echinothrips americanus Morgan (Thysanoptera: Thripidae) was recently (2010) found in the Beijing area and Yangling, Shaanxi Province, China. Current studies report that this thrips uses 48 families-106 species-as host plants, most of which are ornamental plants in the Araceae, Euphorbiaceae, and Apocynaceae families. The host preferences of this thrips among vegetable plants have rarely been studied. The preference for and suitability of 13 potential crop hosts of E. americanus were studied in the laboratory by comparing adult host selection, oviposition preference, and developmental and survival rates. Twelve vegetable species, i.e., Vigna unguiculata, Glycine max (Leguminosae), Daucus carota, Foeniculum vulgare (Apiaceae), Solanum melongena, Capsicum frutescens, Solanum lycopersicum (Solanaceae), Cucumis sativus, Cucurbita moschata (Cucurbitaceae), Brassica chinensis, Brassica campestris, and Brassica oleracea (Brassicaceae), and one non-vegetable host, Medicago sativa (Fabaceae) were tested. One to two weeks-old plants of each crop were grown in a greenhouse into which 100 thrips were released, and plants were examined for thrips infestation daily. The host-plant and oviposition selection data were analyzed with a log-linear model and variance analysis using the software DPS v13.5. The host and oviposition preference of the thrips to the 13 different plant species differed significantly. The most adults were found on C. moschata, with 23.5 per plant, while the plant with the most eggs was C. frutescens, with 50.32 per plant. No adults were found on F. vulgare, B. oleracea, or M. sativa. There were significantly more adults on C. sativus, C. moschata, B. chinensis, G. max, and C. frutescens, more than 10 per plant, than on the other host plants. Additionally, there were significantly more eggs on those five host species-more than 30 per plant-than on other plants, except V. unguiculata. There were no eggs on D. carota, B. oleracea, or M. sativa, suggesting that this thrips does not lay eggs on these plants. There was a positive correlation between the amounts of adults and eggs on the plants; there were usually large numbers of eggs on the plants with many adults. Among the different life stages, eggs required the longest development time, from 6 to 9 days. The developmental duration of prepupae on different host plants was less than 2 days, while the pupal instar persisted longer than the prepupal one. The complete immature phase of the life cycle lasted from 15-17 days on different host plants. Among the tested host plants, this thrips developed fastest on C. sativus, requiring 15.09 days to maturity, and slowest on G. max, with a duration of 16.77 days. The survival rates of the first and second instars were lower (74.6%-94.4%) than those of the prepupae and pupae (93.3%-100%). The first instar had the highest survival rates (94.4%) on B. chinensis and C. frutescens and the lowest rate (74.6%) on C. moschata. Overall, E. americanus had the highest survival rate in the immature stage (80.1%) on C. frutescens and the lowest survival rate (64.3%) on G. max. Our results suggested that C. sativus, C. moschata, B. chinensis, G. max, and C. frutescens were the preferred hosts of E. americanus. This information provides an important basis for assessing the economic threat and invasive potential of this thrips.