In this study, 5 species (Tetranychus kanzawai Kishida, Endoclyta excrescens (Butler), leaf roller caterpillar (Adoxophyes orana Fisher), Anomis mesogona (Walker), and Aulacaspis rosae (Bouche)) were found in Rubus coreanus Miquel in Jeonbuk province, from 2006 to 2008. T. kanzawai appeared in mid-May and showed three peaks in late June, mid-July, and late August. Its density was over 10 adults per leaf. A. mesogona appeared in mid-June and showed two peaks in late July, and early October. Of the 28 insect pests in pre-harvesting, the 7 main species were T. kanzawai, T. urticae, A. orana, Lygocoris lucorum Meyer, Frankliniella intonsa (Trybom), Psylliodes punctifrons Baly and Motschulskyia serrata (Matsumura). Of the 19 insect pests in after-harvesting, the 6 main species were T. kanzawai, E. excrescens, A. mesogona, A. orana, P. punctifrons and A. rosae. Growth of R. coreanus decreased when insect pests were not managed and yields decreased approx. 7% a year. Management of insect pests in field using pesticide was not different.
Economic injury levels (EILs) and economic threshold (ET) were estimated for the two spider mite, Tetranychus urticae Koch (Acari, Tetranychidae) on greenhouse eggplants. T. urticae density increased until the mid-July and thereafter decreased in all plots where initial density of the mite were different each 0, 2, 5, 10 and 20 adults per plant was innoculated on June 7. Growth variables of were not different among experimental plots but fruit weights were lower in plots with higher initial mite density than in plots with lower initial mite density. Total number of fruits and the number of marketable fruits decreased in plots with higher initial mite density. The rates of yield loss increased with increasing initial mite density, resulting in 0, 3.9, 11.3, 14.5, 22.8% reduction in each of the above plots, respectively. The relationship between initial T. urticae densities and yield losses was well described by a linear regression, Y = 1.085X + 2.474, R 2 = 0.9659. Based on the relationship, the number of adults per plant which can cause 5% loss of yield was estimated to be approximately 1.8.
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