Spodoptera 속의 담배거세미나방, 열대거세미나방 및 파밤나방은 여러 나라에 분포하는 광식성 해충으로, 본 연구에서는 이들의 페로몬 및 식물냄새물질과 관련한 화학통신시스템에 대해 이해하기 위해 냄새감각기의 종류와 분포, 냄새활성물질 동정 및 야외행동 반응에 대한 연구를 진행하였다. 주사전자현미경 관찰을 통해, 세 종 나방의 암, 수컷 촉각에 여러 종류의 냄새감각기가 존재하며, 형태적으로 구분되는 종특이적 또는 성특이적 냄새감각기들이 존재한다는 것을 확인하였다. GC-EAD 실험을 통해 세 종 나방에 냄새활성을 나타내는 식물 냄새물질과 페로몬 관련 물질들을 동정하고, 이들을 개별 또는 조합하여 야외 트랩실험을 통해 행동활성을 검정 한 결과, 이 중 여러 물질이 담배거세미나방과 파밤나방의 성페로몬에 대한 유인행동 반응을 저해하는 것을 알 수 있었다. 열대거세미나방은 발생이 저조하여 야외에서의 행동반응을 확인할 수 없었다.
담배거세미나방(Spodoptera litura), 열대거세미나방(Spodoptera frugiperda) 및 파밤나방(Spodoptera exigua) 은 광식성 해충이지만, 종특이적인 기주범위를 갖는다. 이들이 기주식물을 찾아가는 과정에 냄새감각이 어떤 역할을 하는지 알아보기 위해, 기주 및 비기주 식물에서 발산되는 46가지 휘발성 물질을 선정하여, 이들에 대한 나방 3종의 냄새반응을 GC-EAD(gas chromatography-electroantennogram detection)를 통해 확인하였다. 그 결과, 46가지의 식물유래화합물 중 9가지 물질이 3종의 나방 모두에서 냄새활성을 나타냈으며, 2가지 물질은 담배거세 미나방과 열대거세미나방에만 냄새활성을 나타냈고, 다른 몇 가지 물질은 담배거세미나방에만 냄새활성을 나 타냈다. 이 결과는 세 종 나방이 식물냄새물질 탐지를 위해 유사한 냄새감각세포를 가지며, 일부 종에서는 종특이 적인 냄새감각세포가 존재한다는 것을 보여준다. 이 결과를 바탕으로 냄새활성을 나타낸 물질들의 나방 3종에 대한 행동활성을 야외트랩실험을 통해 확인할 예정이다.
호박꽃과실파리(Bactrocera scutellata)는 박과 식물의 해충으로 기주식물을 찾아가는데 냄새 감각이 중요한 역할을 한다. 이들의 기주 식물인 단호박, 애호박, 노란호박 및 하늘타리의 냄새물질을 포집하여 이들 추출물에 대한 호박꽃과 실파리의 촉각과 작은턱수염의 냄새반응을 GC-EAD(Gas chromatography-electroantennographic detection) 및 GC-EPD (Gas chromatography-electropalpographic detection)를 이용하여 조사한 결과, 촉각과 작은턱수염에 존재하는 냄새감각세 포들에 강한 냄새활성을 나타내는 여러 물질들이 탐지되어, 촉각과 작은턱수염 모두 기주식물의 감지에 중요한 역할을 한다는 것을 보여주었다. 하지만, 촉각과 작은턱수염에 냄새활성을 나타내는 물질들의 종류는 서로 확연한 차이를 보여서 촉각과 작은턱수염이 기주식물의 냄새물질 탐지에 서로 다른 역할을 할 것이라는 사실을 나타내었다. 우리는 이들 냄새활성물질의 화학구조 동정을 진행하고 있으며, 이들의 구조가 밝혀지면 이들 물질의 호박꽃과실파리 에 대한 행동활성을 조사할 예정이다.
호박꽃과실파리, Bactrocera scutellata (Hendel) (Diptera: Tephritidae),는 호박 등 박과식물의 해충으로 야외 트랩실험을 통해 호박꽃과실파리 수컷이 cue lure와 raspberry ketone에 유인되는 것이 확인되었으며, 전자현미경 관찰을 통해 호박꽃과실파리의 촉각(antennae)과 작은턱수염(maxillary palps)에 각각 다른 형태의 냄새감각기들이 존재한다는 것을 확인하였다. 이 결과를 바탕으로 Bactrocera 속 과실파리들의 parapheromone 성분들인 cue lure, raspberry ketone, methyl eugenol, 및 zingerone 등의 물질들이 촉각과 작은턱수염 중 어떤 감각기관에 의해 감지되는지 알아보기 위해 이 물질들과 식물 냄새성분인 3-octanone에 대한 호박꽃과실파리의 eleltroantennogram (EAG) 및 electropalpogram (EPG) 반응을 측정하였다. 그 결과 cue lure 및 raspberry ketone은 작은턱수염에서 큰 EPG 반응을 보였으나 촉각에서는 EAG 반응을 나타내지 않았다. 이와는 대조적으로 호박꽃과실파리의 기주식물인 호박에서 방출되는 냄새 성분 중 하나인 3-octanone은 촉각에서 큰 EAG 반응을 나타내었으나 작은턱수염에서는 아주 작은 EPG 반응만을 나타내었다. 이러한 결과는 호박꽃과 실파리 수컷에 강한 유인력을 나타내는 cue lure와 raspberry ketone이 촉각이 아니라 작은턱수염에 존재하는 냄새감각세포들에 의해 감지된다는 것을 의미하며 이것은 호박과실파리 등 아직 강력한 유인제가 알려져 있지 않은 다른 과실파리류의 유인제 개발에 유용한 정보가 될 것이다.
Entomopathogenic fungus is a useful control agent to sucking type insect such as whitefly and aphid. The fungi are influenced by some environmental factors such as relative humidity, temperature and UV and cause slow and fluctuation in pest control efficacy. Especially, UV kills conidia or spores of entomopathogenic fungi and a mycopesticide using fungi has short control period in field. UV intensity changes from season to season. Survival rate of entomopathognic fungi treated may differ from seasons and will show different control efficacy. Therefore, we conducted a study to estimate the persistence of an Isaria javanica isolate, which was already reported as sweet potato whitefly control agent, in potted greenhouse soil planted different crops. The number of survival spore decreased gradually and differ from seasons.
Grapholita dimorpha is a new pest of apple, pear and plum in Japan and Korea as well. Although G. dimorpha was reported as a multi-voltine insect with four generations per year, the phenology is not fully known in Korea. We present a model to predict the spring occurrence of G. dimorpha adults based on the relationship between the cumulative proportion of G. dimorpha adult catches and accumulated degree-days. Five different distribution models were applied and the selection was made based on the statistical information criteria (AICC and BIC). Model validation was performed with the field data of the male moth catches in sex pheromone-baited traps of two apple production regions (Chungju and Geochang) of Korea in 2011. Model predictions of the dates for the cumulative 50% male moth catches were within five days variation. Because G. dimorpha has a feeding habit of boring inside the fruit the management practice of G. dimorpha should apply on egg and neonate larval stage. The management strategy of G. dimorpha in spring might be improved by the model.
Understanding the spatial pattern of G. molesta and the temporal variation of their patterns are important to develop and maintain pest management programs in fruit orchards. The overwintering larvae of G. molesta pupate early in the spring and new adults begin a flight for several reasons such as mating, seeking resources (food or shelter) and oviposition. It was known that G. molesta presented “low movement activity” and male G. molesta flight behavior was closely related to the proximity of its host crops. Unmated males remain near the site of emergence in order to find and copulate with unmated females. The fruit-bearing status of orchards are important factors for G. molesta movement. To elucidate the spatial distribution and temporal variation of G. molesta within and among orchards, pheromone traps targeting male G. molesta were used because the trap represent a reliable and economic tool for monitoring adult G. molesta populations. The study was conducted in two apple orchards (one is isolated from other fruit orchards and another is surrounded by apple orchards), Andong and in seven plum orchards, Uiseong, 2010. Using spatial analysis by distance indices, the spatial pattern of G. molesta in each sampling date was presented. In the study of the spatial pattern within apple orchard, the index of aggregation (Ia) of isolated orchard were presented >1, indicating an aggregated distribution pattern, from monitoring results. The spatial association between successive monitoring using X (the index of spatial association) was negative during spring season and after then the value was changed to positive. In the experiment of the spatial pattern among orchards, the index of aggregation was >1 in most monitoring date and the index of spatial association was negative during early and late growing season. Factors influencing the spatial-temporal dynamics of G. molesta are discussed.
Grapholita molesta, G. dimorpha and C. sasakii as “internal feeders” are important apple pests in Korea. Three species overwinters around and in apple orchards. New young larvae of three species bore into new shoots or fruits and then feed inside apple. When mature larvae escape from fruits they make holes that reduces the commercial value of fruit. Therefore, understanding the phenological distribution of three species is critical to establish the precise management system for reducing three species population. The study was conducted to investigate the adult emergence of G. molesta, G. dimorpha and C. sasakii using pheromone traps and to forecast the cumulative proportion of each population. This study is second part of consecutive experiment. Data collection was carried out on three commercial apple orchards and one experimental orchard of Giran in 2010 and 2011. The experimental process was same in the study of plum. More than 50% of G. molesta male was occurred in spring season (within 500 degree-days), 2010 and 2011. The adult emergence of G. dimorpha and C. sasakii was linear and sigmoidal pattern in each year. The phenology of C. sasakii was explained well by nonlinear functions and the equation 3, 6, 8 and 11 were selected based on AICc and BIC. The selected equations were validated by the data of present year (2011) in each region. The performance of G. molesta and G. dimorpha was analyzed well by bimodal functions. The importance of phenological model is discussed to develop and maintain a more precise system for multiple pest management on apple orchard.
The study was conducted to investigate the phenological distribution of G. molesta, G. dimorpha and C. sasakii and to estimate the emergence timing of three species in plum orchards. It was known that G. molesta and G. dimorpha are a multi-voltine insect and C. sasakii has one to two generations depending on temperature and geographic location. Three species damage to many economically important fruit tree such as plum, pear, peach and apple. The main emergence time of each species is different depending on host plant and environmental conditions, specially temperature. Therefore, if we have the information of population density and low temperature threshold of a species and air mean temperature of a region in previous year we can predict the phenology of a species in present year. This is one part of consecutive research. Data collection was carried out in seven plum-growing commercial orchards of Uiseong in 2010 and 2011. The commercial pheromone monitoring traps (GreenAgroTech) were used to investigate the flight phenology of three speices. The record of temperature was received from meteorological center close to monitoring orchards. The relationships between degree-day accumulated above the low temperature threshold and cumulative proportion of accumulated moth caught of previous year was used to predict the phenology of three species in present year. The results of G. molesta and G. dimorpha estimated by bimodal functions were better than those analyzed by nonlinear functions. The phenology of C. sasakii was analyzed well by nonlinear function and the equation 3, 6, 8 and 11 were selected based on AICc and BIC. The selected equations were validated in each orchard.
Pollinating insects function significantly in structuring ecosystem as well as agricultural production. Among the variety of pollinators, Osmia cornifrons is one of the important pollinators in apple orchards. Unlike honey bees, O. cornifrons is able to pollinate at low temperature that facilitates its wide commercial use. The female O. cornifrons in nature lay their eggs to the interior of the bamboo reeds where they spend their larval and pupal stage throughout the summer and during fall they overwinter as adult. The adult bee emerges from the overwintering cocoon in the spring seasons. Since the complete synchrony with flowering period is critical, farmers collect and store the dormant state of O. cornifors in cold storage and expose them in due time to outdoor temperatures for their emergence, pollination activity can be performed. However, information on biological and ecological requirements for the emergence of overwintering adults are rarely reported. We carried out the experiments on temperature dependent adult emergence and constructed the emergence model based on developmental rate and distribution. Parameters were estimated from linear model and weibu