THE SUITABILITY OF KOREAN PINE (PINUS-KORAIENSIS SIEB ET ZUCC) AND JAPANESE RED PINE (P-DENSIFLORA SIEB ET ZUCC) AS A HOST OF THE JAPANESE PINE SAWYER, MONOCHAMUS-ALTERNATUS HOPE (COLEOPTERA, CERAMBYCIDAE)

The suitability of two pine species, Pinus koraiensis and P. densiflor a, as a host of the Japanese pine sawyer, Monochamus alternatus HOPE w as compared. The larval entrance holes and overwintered larvae were di stributed primarily around the middle section of the P. densiflora tru nks, whereas in the case of P. koraiensis trunks, they were scattered in the middle to lower portions. These distribution patterns were simi lar to those of the oviposition slits in each of the pine species. The density of the entrance holes and of the overwintered larvae in P. ko raiensis was higher than in P. densiflora, as was the survival rate ov er hibernation estimated from these two values. Both in 1988 and in 19 89, the beetles emerged somewhat earlier from P. densiflora than from P. koraiensis. The weight gain per feed unit among the beetles fed on one-year old P. densiflora shoots was greater than it was in beetles f ed on shoots of P. koraiensis. During the first three days after emerg ence almost all beetles showed a preference for P. koraiensis when pre sented with the two pine species simultaneously. These results suggest ed that P. koraiensis is similarly suitable or rather superior as a ho st for the Japanese pine sawyer to P. densiflora.