The two-spotted spider mite Tetranychus urticae is being steadily problematic on strawberry. To effective control of this pest, one combination application using predatory mite Phytoseiulus persimilis plus a pesticide Acequinocyl suggests. Prepared six beds (1.5 × 3 m; 20 strawberry plants) on glass house, 100 T. urticae was inoculated on per 20 plants. Four plots prepared - Acequinocyl treatment, P. persimilis application, Acequinocyl+P. persimilis double application, and the control. The change of T. urticae density was investigated in the seven-day intervals. In an Acequinocyl treated plot, T. urticae density was decreased after Acequinocyl sprayed, but began to increase steadily one month later. In a P. persimilis applied plot, T. urticae density began to decrease at 20 days after P. persimilis inoculation. In an Acequinocyl + P. persimilis double applied plot, T. urticae density was dramatically decreased after application and then no found the T. urticae. To practical use in farmhouse, it will be possible to control by inoculation of P. persimilis only when low density of T. urticae; however, double application with spray pesticide Acequinocyl plus apply the natural enemy P. persimilis will be good when high density of T. urticae.

As increased the cultivating areas of several minor crops for medicine such as Glycyrrhiza uralensis, Astragalus membranaceus, Taraxacum platycarpum, Gynanchum wilfordii, and Purple granadilla, the occurrence of major pests and their damages were severed. Primarily occurred pests on five minor crops were observed small in size pests such as whiteflies, aphids and thrips, but the other pests are insignificantly infest. Whiteflies showed higher density in G. uralensis but its damage was insignificant level. Aphids were showed higher density at June in all minor crops and then sharply decreased the density with lower degree of damage. The high damage on initial growth stage will be judge to affect on the yield. Thrips on T. platycarpum showed higher density with 44.1%, compare to other crops, sharply increased the density in late-June and optimal peak in mid-July and decreased in late-Aug. Conclusively, major pests on crops, green peach aphid, mites species on A. membranaceus and G. uralensis, olender aphid, mites species and thrips on G. wilfordii were damaged. Detailed investigation and analysis for economic value of the damaged pest for the continual production will be promoted and then followed the procedure the registration of agrochemicals.

This study was investigated the seasonal occurrence of Metcalfe pruinosa (Say) in Chungbuk province and established the optimal control timing. Population densities of nymph and adults were investigated and egg hatching period and oviposition period was examined from three locations (Cheongwon, Jincheon, Eumseong area). Egg hatching period was investigated. The first day of egg hatching observed on May 25, the day of peak egg hatching was on May 29, and the perfect accumulative egg hatching ratio was on Jun. 13. Oviposition period of M. pruinosa female was observed the cut branch (cut within 10 cm length, 1 cm dia.) of oak tree, an althea, and an acacia under stereoscope. The first oviposition was observed at Jul. 28 and continually increased until late-Sept. with sharply increased at mid-Aug. Population density of M. pruinosa nymph was observed the cut branch (cut within 30 cm length, 1 cm dia.) of oak tree, an althea, an acacia, and pear tree. Population density began decreased showing after highest density with 25.3 (Jul. 1). The adult was first appeared at Jul. 11 and showed highest population density with 13.1 (Aug. 4) and then continuously decreased. To control M. pruinosa at pear orchard, optimal control timing for nymph was judged from Jun. 13 to Jul. 2, because of its small size of body and exuviae, low damaging by honeydew producing, low wax materials produced. Second control timing was judged at early Aug., when the adult invading to the pear orchard from near forest and the period before oviposition. The control agents for M. pruinosa were not yet registered, but will be anticipated to register the chemicals such as penitrothion WP, acetamiprid WP, dinotefuran WP, lambda cyhalothrin, thiamethoxam SP in 2012.