Lettuce was a leaf vegetable with short growing term and cold-tolerant plant. We grew it the whole year. The price of lettuce is the most expensive from July to September. But damages by lots of insect pests appear to greenhouse grown lettuce in summer season. In this study, we observed biological controls of western flower thrips(Franklinella occidentalisi) by the predator mites, Amblyseius swirskii and Neoseiulus cucumeris in lettuce greenhouse from July 7 to September 10. Hypoaspis aculerfer larvae and adults were released 30 individuals per m2 at the first one time as lettuce was planted on the greenhouse. We checked the density of F. occidentalis every 10 days on the 30 lettuce leaves. When the population of F. occidentalis reached 1~5 individuals per a leaf, A. swirskii larvae and adults were released 35 individuals per m2 at 1~3 times and Neoseiulus cucumeris larvae and adults also were released 150 individuals per m2 at 2~3 times in each lettuce greenhouse. During the high temperature season, Amblyseius swirskii was more effective biological controls of F. occidentalis than Neoseiulus cucumeris.

Blossom midge, Contarinia maculipennis Felt (Diptera: Cecidomyiidae) is originated in Southeast Asia and has been present in Japan, USA and Hawaii. Recently, C. maculipennis was intercepted in Japan, USA and Netherlands with orchid flowers imported from Southeast Asian countries. This pest is designated as quarantine pest in Korea because of its potential damages to vegetables and ornamental plants in case when this pest introduced in Korea. C. maculipennis has known to feed inside unopened flower buds, causing deformed, discolored buds and blossoms. And, in severe infestations, cause premature bud or blossom drop. In Korea, similar damage symptoms have been reported in western orchids which mighty be caused by C. maculipennis from Mid-2000s, especially on D. phalaenopsis. An official recognition to C. maculipennis was given in 2007. And, the occurrences of C. maculipennis and its damages were investigated mainly on D. phalaenopsis in 2008~2009. We emphasize caution about recognizing the possibilities that C. maculipennis could infest flower buds of an orchids and carry out management strategies for this pest in the future.