Âü°í¹®Ç塽 1. beers, e. h., j. h. brunner, m. j. willett, and g. m. warner. 1993. orchard pest management. good fruit grower, yakima, washington. 276pp. 2. burts, e. c. 1970. the pear psylla in central washington. wash. agric. stn. circ. 516. 3. butt, b. a., and c. stuart. 1986. oviposition by summer and winter forms of pear psylla(homoptera: psyllidae) on dormant pear budwood. envirn. entomol. 15: 1109-1110. 4. follett, p. a., b. a. croft, and p. h. westigard. 1985. regional resistance to insecticides in psylla pyricola from pear orchards in oregon. can. entomol. 117: 565-573. 5. goryshin. 1955. the realtionships of light and temperature factors in the photopeiodic reaction of insects. entomol. obozrenie 34: 9- 13. 6. ±èµ¿¼ø. 1996. ²¿¸¶¹è³ª¹«ÀÌ »ýÅÂ¿Í ¹æÁ¦. ¿¬±¸¿Í Áöµµ 37: 32-23. 7. mcmullen, r. d., and c. jong. 1976. factors affecting induction and termination of diapause in pear psylla(homoptera: psyllidae). can. entomol. 108: 1001-1005. 8. oldfield, g. n. 1970. diapause and ploymorphism in california poulations of psylla pyricola(homoptera: psyllidae). ann. entomol. soc. am. 68: 59-60.