Potato tuber moth (PTM), Phthorimaea operculella (Zeller), is a serious pest of potato (Solanum tuberosum L.) plants in the fields from warm temperate to tropical climates, and tubers stored under ambient temperatures post-harvest. In recent years, concerns on PTM occurrence and damage to potato are increasing due to climate change resulted in global warming. To search potent natural enemies of PTM, we collected >150 PTM larvae from potato fields in Jeju-do in May, 2009 and then reared in the room until wasp adults emerging, which was identified by Lee J.W. as Diadegma fenestrale (tentative Korean name, 감자뿔나방맵시벌). This is the first report in Korea. When supplied 10% sugar solution on adults to rear, the longevity was 12.2±2.0 day, which was much longer than supplied with only water (5.0±1.4 day) or none (3.1±1.1 day). When the 2nd larvae of PTM, 10 days after hatch, dwelled in potato tubers were supplied to parasitoid adults for parasitization, the developmental periods from egg oviposition to adult emergence was 24.0±2.9 day, and the sex ratio of newly emerged adults was 0.27. The parasitization ratio indoor showed a kaleidoscopic characteristics, ranged from 30.0% to 71.4%. It represented that many factors might be related for the successful parasitization to PTM larvae.

Potato tuber moth (PTM) has been a destructive pest on potato in the fields and strores through tropical to subtropical area. According to global warming, PTM distribution limit in Korea is facing north gradually. Recently, potato fields damaged by PTM are reported intermittently in the midsection of a country and southward. To secure a sufficient number of insect with equal growth stage is a prerequisite for investigating bionomics and developing new agrochemicals to control pests. In 2009, we collected PTM larvae first from the potato fields in Miryang and Gimcheon, and then placed them into transparent hexagonal rearing cage (30×30×30cm) with providing potato tubers as a food till emergence. A transparent cylindrical rearing cage (Φ15×30cm) erected vertically before putting emerged adults, and covered upper opening with net (50 mesh). To get eggs, we placed a filter paper (Φ11cm, called ‘oviposition paper’) on the net and sprinkled sugar solution. The oviposition paper laid eggs was stored in 10℃ refrigerator and changed with new one every 1~2 day interval. The developmental period of eggs to hatch was 5.2±0.7 days at 23±2℃, L16/D8 condition. Although adults laid eggs continuously for two weeks, second to fifth days after emergence showed highest oviposition, which suggested the most efficient periods for collecting sufficient eggs. A hatchability of eggs laid within 10 days after emergence was over 90%.

절편씨마를 이용하여 마를 재배할 경우 토성에 따른 괴경의 형태적 특성과 수량성의 차이를 단마 품종 '마1호'와 장마 품종 '안동재래종'을 공시하여 검토한 결과를 요약하면 다음과 같다. 사토에서는 괴경의 길이가 짧고 분기의 발생이 많아 괴경의 모양이 좋지 않았다. 양토와 사양토에서는 사토에 비하여 분기 발생이 적어 괴경의 모양이 양호하였으며, 괴경의 생체수량은 단마가 21~27%, 장마가 각 6% 증수되었고 , 상마수량은 단마가 45~55%, 장마가 20~22% 증수되었다. 식양토에서 단마는 괴경의 분지 발생이 다소 많았으며, 장마는 괴경의 굵기가 가늘고 만곡되어 모양이 좋지 않았다.

마 재배에 있어서 트랜쳐를 이용한 심경재배 효과와 트렌치 깊이에 따른괴경의 형태적 특성 및 수량성의 변화를 자주식 보행형 트렌쳐인 "NF-827H"를 공시하여 검토한 결과를 요약하면 다음과 같다. 트렌처를 이용한 심경으로 마를 재배하면 관행 경운에 비하여 괴경의 크기가 커지면서 모양이 좋아지고 상품성이 높은 괴경의 수량이 크게 증가되었다 트렌치에 의한 심경재배 효과는 단마보다 장마에서 크게 나타났으며, 괴경의 크기와 모양 및 수량성을 고려할 때 단마는 60cm 이상, 장마는 80cm 이상으로 트렌치하는 것이 좋다.

To give some information on the harvest and storage of Chinese yam (Dioscorea opposita), the experiment was done to examine the effect of its harvesting date and storage method on tuber weight, tuberrelated characters during the storageor at the end of storage. The yam tubers harvested 4 times at 20 days interval from Oct. 15 were stored with different storage methods(pit, room and cold temperature) and on Mar.15. all the characters were measured. Fresh weight of the tuber harvestedafter Nov. 5 and stored were greater than that done on Oct. 15 while dry tuber weight did not have any difference between the harvesting dates. The fresh weigth done directly from the field on Mar. 15 was higher compared to the other harvesting dates owing to its higher moisture content. The rate of sound tuber stored at room or cold temperature condition was higher than that at the field at which the rate was greater at the harvest after late nov. compared to the earlier harvests. Although the two storages were similar at sound tuber rates and marketable yield, the tuber weight was more reduced when stored at room temperature than when done at cold temperature . Brightness and value 'b' of chromaticaity realted to the tuber coloring and sugar content were higher but moisture content was lowerwhen harvested on Oct. 15 than the other havesting dates. All the characteristics realted to the marketability after storage were nearly same when stored at room and cold temperature. Value 'a' of chromaticity and sugar content were higher when harvest on Mar. 15 than when harvested before Dec. 15 but the 'b' value and mositure content were reverse results.