본 보고에서 서해안 개소의 매개 진딧물 밀도가 대관령에서의 밀도보다 대체로 낮았으나 장소에 따라서는 상당히 높은 사실을 밝힌바 있다. 새 감자의 평지생산방식이 현행방식보다 합리적이어서 유리하므로 그 생산휴계의 확립을 위한 기초자료를 얻고자 본 조사에 착수하였다. 서해안 답작물지대에서의 진딧물 발생원은 부락이므로 여기서 얼마나 떨어진 곳이라야 안전하게 씨감자를 재배할 수 있을 까를 위하여 전북 김제군 광활면 옥포리를 택하여 이곳을 중심으로 1.5km 평방지구내 13개소에 동서남북으로 250m 거리를 두고 진딧물 채집기을 설치하여 1968년 7월 21일부터 10월 31일까지 수집된 진딧물을 매일아침에 채집하여 종명을 밝혔다. 감자바이러스 매개 진딧물이 세계적으로 20종 알려져 있는데 우리나라에 있는 것은 10종이며 이 지역에서 발견된 것은 복숭아 흑진딧물(Myzus persicae), 목화진딧물(Aphis gossypii), 싸리수염진딧물(Aulacorthum solani), 무테두리진딧물(Lipaphis erysimi) 및 국화꼬마수염진딧물 (Macrosiphoniella sanborni)의 5종이었다. 중락중심지에서의 매개진딧물 밀도는 내릉의 수원에서의 그것 보다도 높았으나 여기서 불과 250m만 떨어져도 대관령에서의 밀도 보다 낮아졌다. 그러나 조사지점의 환경에 따라 상당한 차이가 있다. 즉 매개 진딧물의 기주식물이 있는 인가와의 거리에 따라 달라진다. 추작용 씨감자의 현재산지인 전남의 일모, 경남의 락은 내륙의 부락근방이라서 매개진딧물 관계로 부적당하다고 본다. 전문가의 식물역학적 진단에 의해 서해안 답작지대중 매개 진딧물이 적은 곳을 택해서 씨감자를 생산한다면 우수한 씨감자를 양산할 수 있다. 씨감자 부족량 60,000톤을 충족시킨다면 증수(년간 250만톤)할 수 있어 농가소득증대는 물론 남는 감자는 전분원료로서 단경기에 공급할 수 있으며 일부를 사료화할 수 있고 우수한 씨감자는 외국에 수출할 수 도 있으며 전북 서해안의 광대한 일모작지대를 이모작지대로 만들 수 있다.

Present system of seed potato production in Korea has several weak points and consequently has difficulties in covering annual shortage of 60,000 tons of seed potatoes. The author has an opinion that this so called 'High land system' of seed potato production adopted by the Government should be replaced by the 'Coastal area system' which is proposed by the author and has many advantages over present 'High land system'(2). In coastal areas where enormous acreage of rice paddies are spread, mostly around the villages. the primary host plants of the vectors are found. Therefore, the only source of aphid vectors are limited to the villages. The farmer's houses scattered more sparsely also have minor importance. In the previous paper(2), the author reported that the aphid vector populations were lower in the coastalareas than at Taegwanryong where the Alpine Experiment Station for the production. of seed potatoes is located. However, the number to vectors at Okku showed rather high density, where the trap was placed at the distance of 200 m from a village where peach and Hibiscus trees, the primary hosts of Myzus pesrsicae and Aphis gossypii were grown. To clarify the flight distance from the source of the aphid vectors, a trial was carried out in the Kwanghwal area, Kimje-gun, Cholla-pukto. on the western coast. 13 traps were placed at four directions and the distances between the traps were 250 m. (Fig. I) The traps 'Were operated from June 21 to October 31. The results are shown in Table 1. A total of some 70 species of aphids were found, including 5 speceis of potato virus vectors. The vectors are as follows: I. Myzus persicae (Sulzer) 2. Aphis gossypii Glover 3. Aulacorthum solani (Kaltenbach) 4. Lipaphis erysimi (Kaltenbach) 5. Macrosiphoniella sanborni (Gillette) Out of a total of 12,797 aphids, 5,187 vectors were found. The trap catches at the 13 locations are shown in Fig. 2 and the numbers of the vectors at each location for each vector, except Macro-siphoniella sanborni. of which only a single individual was caught, are shown in Fig. 3-6. Number of vectors at C (3,279) (Centre of the village) is considerably higher than that at Suwon (763), however, EI. SI. WI and NI. where the distanecs from Care 250 m, showed lower numbers of vectors than that at Taegwanryong (347). The number of vectors at NI was rather than at the other 3 locations at the distance of 250m from the village. This was because C was in the southern part of the village. Consequently NI was much closer to the village than the other 3 locations of the same distance from C. Numbers of catches of the most important vector. Myzus persicae, are shown in Fig.3. The distribution pattern is typical except , where several farmer's houses were found. If only the rice paddies were found in these locations. the numbers of the vectors would be small as the distances increase. Numbers of catches of the other 3 vectors are shown in Fig. 4-6. From these results. the author has drawn the following conclusions: 1. The aphid vector sources at the rice paddy belt in the western coast are the villages. 2. The vector densities at the locations where the distances are 250 m from the centre of the village are lower than that at Taegwanryong. 3. The vector densities become gradually lower as the distances from the centre of village increase. However. depending on the host plant situation at each location, the vector densities are variable. These minor sources of aphid vectors may be eliminated so that seed potatoes can be grown. 4. Thus. under the direction of specialists, fields suitable for seed potato production can be found in the coastal areas.

• 白雲夏