Whitefly (Hemiptera: Aleyrodidae) pests, including the sweetpotato whitefly, Bemisia tabaci, and the greenhouse whitefly, Trialeurodes vaporariorum, are economically important in agriculture. With the annual growth of the domestic fresh fruit export market, various quarantine treatment methods are being used to export strawberries of better quality. The purpose of the present study was to investigate the effect of ionizing radiations (electron beam, X-ray, gamma-ray) on the development and reproduction of two species of whitefly and to determine the optimal dose of three ionizing radiations for the construction of quarantine technology applicable to strawberry export.

Whitefly (Hemiptera: Aleyrodidae) pests, including the tobacco whitefly, Bemisia tabaci, and the greenhouse whitefly, Trialeurodes vaporariorum, are economically important in agriculture. With the annual growth of the domestic fresh fruit export market, various quarantine treatment methods are being used to export strawberries of better quality. The objective of the present study was to evaluate the effects of gamma rays on the development and reproductive sterility of B. tabaci and T. vaporariorum. In both species, the eggs were completely inhibited from hatching at 50 Gy, and the emergence of 3rd instar nymphs was completely suppressed at 150 Gy. Some adult B. tabaci and T. vaporariorum spawning occurred at 100 Gy and 70 Gy, respectively; however, at these irradiation levels, F1 hatchability was completely inhibited. Dosimetry results showed that the penetrating power of gamma ray in the strawberry-filled box was the lowest at the mid-box position. Therefore, B. tabaci and T. vaporariorum were placed in the middle of the strawberry-filled box and irradiated. A gamma-ray irradiation of 100 Gy suppressed the development and reproduction of eggs and adults in both B. tabaci and T. vaporariorum. However, the development of 3rd instar nymphs was inhibited at 300 Gy for B. tabaci and 200 Gy for T. vaporariorum. Our data suggest that at least 300 Gy should be used for the control of these two types of whitefly for strawberry export.

Tomato yellow leaf curl virus (TYLCV) and its vector insect, the sweet potato whitefly Bemisia tabaci, are major threats to tomato and pepper production in all around world. Since the last three decades, both B. tabaci and TYLCV have been invaded into many countries via different routes. Our studies showed that various geminiviruses including TYLCV can be transmissible by seeds as well as whiteflies. Furthermore, commercially developed resistant tomato strains against TYLCV infection can serve as TYLCV reservoirs and potentially influence on TYLCV epidemics. Therefore, transmission pathways through both insect vectors and seeds should be concerned for suitable management of geminiviruses and whiteflies.

Vector-borne plant virus transmission is a complex mechanism. Plant viruses modify development and behavior of vectorinsects in a positive, negative, or neutral manner. Bemisia tabaci transmits Tomato yellow leaf curl virus (TYLCV) whichis a virus that seriously damaged tomato cultivars all around the world. We compared several behavioral and physiologicalcharacteristics between non-viruliferous (NV) and TYLCV-viruliferous (V) of whiteflies. When B. tabaci acquired TYLCV,total life span was shorter and fecundity was lower than NV ones. V whiteflies were more susceptible to thermal stressby increasing hsp mRNA levels but higher in mortality by either heat or cold shocks. Further, V whiteflies increasedthe rates of plant sap probing and light attraction behaviors than NV ones. Our results provide insights to understandvector’s role in relation to the acquisition and transmission of plant viruses.

The toxicity of neem extracts that induce abnormality and lethality is strongly enhanced by the ingestion rather than surface contact. Oral toxicity of neem extracts was analyzed using a plant sapping pest Bemisia tabaci. When adults were allowed to ingest various doses (0, 5, 10, and 50 ppm) of azadirachtin diluted in 20% sugar solution in a double-layered parafilm chamber for 72 h, mortality was 12.5, 77.5, 97.5, 100%, respectively. When a cucumber leaf which has many nymphs were submerged into the solution of neem extract, adult eclosion was decreased to 87.0, 16.6, 16.1, and 6.6%, respectively. Further, when neem extracts were irrigated into the tomato cultivar the average number of nymphs per leaf was decreased to 60.3% in comparison with the untreated control. These result suggest that systemic treatment of neem extracts was effective for the control of whiteflies as well as other sucking insect pests.

Tomato yellow leaf curl virus (TYLCV) causes a highly serious disease in tomatoes in many countries. The most important thing in management is the prevention of virus transmission. TYLCV had been known to be only transmitted by a vector, the sweetpotato whitelfy, Bemisia tabaci. However, we identified two other important routes of TYLCV transmission into tomatoes. It is seed-transmissible. Many seeds available in domestic and global markets were infected by TYLCV. It is also infective into various weeds and other horticultural crops and transmit virus through vector insects. Therefore, we need a new strategy for the virus and vector management.

Whiteflies (Hemiptera: Aleyrodidae) and thrips (Thysanoptera: Thripidae) are major pests on greenhouse crops including sweet pepper (Capsicum annuum L.) in South Korea. To manage this pest complex effectively, it is fundamental to understand population dynamics and spatial distributions of the pests. In this study, we conducted visual counting and used yellow sticky traps to monitor whitefly and thrips populations in sweet pepper greenhouse (6 × 28 m). The survey was conducted every two weeks over two months. A total of 84 traps were set up at 20cm from the plant top canopy and spaced 1m apart from each other. Leaves were selected randomly from the middle plant canopy for visual counting at the same sampling locations. The trap data indicate that the numbers of whiteflies and thrips increased from 5.50 ± 0.34 to 168.51 ± 14.95 and from 52.40 ± 1.67 to 158.42 ± 7.44 (mean ± SE) per trap, respectively, over the two-month observation period. In general, the spatial distributions of these pests aggregated near the greenhouse entrance with significant positive correlation between the densities of the two species (r = 0.74, P = 0.02). However, the results of visual counting were completely different; either species was rarely found on leaves, even when the trap catches were relatively high at the same locations. That is, there was no correlation between visual counting and sticky trap data sets. The current study will serve as a fundamental step to develop reliable and effective management programs for greenhouse sweet pepper.

We collected the unknown species of whiteflies throughout the Chungnam districts. Crepidiastrum sonchifolium (Bunge) Park & Kawano, Korean youngia was major plant to Cabbage whitefly and discovered throughout the Chungnam province in 2013. The unknown other species was collected on leaf of Morus alba L.(White mulberry) in September, 2014. We are attributing this species to Parabemisia sp. It has been known that plants affected by Aleyrodes proletella Linnaeus, cabbage whitefly are leafy brassicas, including kale cabbage, broccoli and Brussels sprout and a minor pest of cabbage, bruseels sprouts and broccoli in Europe, being seldom a pest of agriculture but often troublesome to home gardeners. In cage of pupal, lingular head is simple, dorsal submargin without row of papillae and body not boxshaped. The pupal shape of Parabemisia sp.(attributted) is as follows. The fourth nymphal skin has 30 to 32 marginal setae including the caudal setae. The anterior spiracular furrows are scarecely visible, but the caudal furrow is slightly ridged longitudinally. The vasiform orifice is elongate triangular with the lingula included. The lingula has two blunt lateral tubercles and two long caudal lingular setae. The operculum covers only the anterior one-third of the vasiform orifice. In vivo, the nymphs are surrownded by a marginal fringe of clear wax.

Whiteflies harbor several secondary endosymbionts, which are maternally inherited from mother to offspring, that have major effects on host preferences, biology, and evolution. Here, we identified Wolbachia bacteria in sweetpotato whitefly (Bemisia tabaci) as well as whitefly popluations from other countries by comparison of 16S rDNA sequences. Wolbachia were detected in all tested indigenous B. tabaci populations (Bangladesh, Myanmar, Nepal, and the Philippines) as well as Q1 biotype of Korea, whereas they were absent from B biotype of Korea and Q biotype of China. Wolbachia were also detected in all five tested Aleurodicus dispersus populations as well as Tetraleurodes acaciae, whereas they were not detected in all seven Trialeurodes vaporariorum populatuions. In addiiton, Wolbachia were detected in parasitic wasp (Encarsia formosa) of B. tabaci as well as honeybee (Apis mellifera). Among the 19 whitefly populations from different countries, our analysis identified four phylogenetic groups of Wolbachia, thereby demonstrating the high diversity of this genus. Wolbachia phylogeny suggests a correlation of geographical range with ecological variation at the species level.

본 연구는 친환경적이며 효과적인 시설내 가루이 예방 및 방제를 위해 이류체 포그시스템을 이용하여 올레산을 분무할 때, 올레산의 적정농도를 구명하고 3회 처리시 방제가를 조사하기 위해 수행되었다. 올레산의 적정농도 실험은 부여토마토시험장 단동형 플라스틱온실에서 공시품종으로 도태랑골드를 사용하여 수행했고, 올레산의 3회 처리시 방제가에 대한 실험은 경기도농업기술원 벤로형 유리온실에서 공시품종으로 로쿠산마루를 사용하여 수행했다. 적정농도 실험은 무처리구를 대조구로 하고 올레산 2000ppm과 4000ppm을 각각 처리하고 가루이의 밀도를 조사했다. 3회 처리 실험은 화학살충제 처리와 동일하게 올레산 2000ppm을 2일 간격으로 3회 처리하고, 2일 후에 방제가를 조사했다. 이류체 포그시스템은 실험기간동안 올레산을 처리하지 않을 때에는 오전 8시부터 오후 5시까지 온도가 25℃ 이상이거나 습도가 75% 이하로 내려갈 때 180초 작동 후 30초 휴식을 반복하여 작동했고, 올레산을 처리했을 때에는 오전 11시부터 오후 5시까지 동일한 조건으로 작동했다. 올레산의 농도실험에서는 2000ppm에서 81.6%, 4000ppm에서 93.6%의 방제가를 나타냈다. 즉, 농도를 높게 처리할수록 가루이의 밀도는 크게 감소했다. 올레산 3회 처리 실험에서는 2000ppm을 3회 처리했을 때, 농약등록 기준보다 높은 85.8%의 방제가를 나타냈다. 따라서 올레산을 2000ppm 이상 3회 처리하는 것이 친환경적인 가루이의 예방 및 방제에 매우 효과적인 것으로 나타났다.

토마토 시설재배에서 고온기에 온습도를 조절할 목적으로 사용되는 이류체 포그시스템이 가루이 방제에 미치는 효과를 알아보고, 이를 활용한 효과적이고 친환경적인 가루이 예방 및 방제 방법을 모색하기 위해 총 2회에걸쳐실험을수행하였다. 1차실험에서는 포그처리의가루이 방제 효과를 구명하였고, 구역별가루이 분포를조사하였다. 2차실험에서는 이류체 포그시스템이가루이의 수직분포와 운동성에 미치는 영향 및 방제효과를 검증하는 실험을 수행하였다. 1, 2차 실험에서 이류체포그시스템이 가루이의 개체수와 운동성을 감소시키는 효과가 인정되었다. 시설 내에서 가루이는 출구에서 먼쪽의구역에높은 밀도로 분포하며, 이류체 포그시스템을 작동하였을 때 가루이의 수직분포가 달라지는 것이 조사되었다. 따라서 이류체 포그시스템을 가루이의 예방및방제에 사용하되, 밀도가 높은구역의기주식물 중상부에 황색점착트랩을 설치하여 가루이를 더욱효과적으로 방제할수있을 것으로사료된다.

본 연구는 이류체 포그시스템과 천연물을 이용하여 효과적이고 친환경적인 가루이 예방 및 방제 방법을 구명하기 위해 수행되었다. 실험은 단동형 플라스틱하우스에서 공시품종으로 비타미니를 사용하여 총 4회 수행되었다. 1차 실험에서는 별도의 습도조절 없이 이류체 포그시스템을 작동하였다고, 2차 실험에서는 이류체 포그시스템으로 습도를 70% 이상으로 제어하였다. 3차 실험에서는 이류체 포그시스템으로 1.5mg/L Neem Oil을 분무처리하였고, 4차 실험에서는 2mg/L 농도의 Oleic acid를 분무처리하였다. 1차 실험에서 분무처리구의 가루이의 밀도는 크게 감소하였다. 2차 실험에서는 1차 실험보다도 분무효과가 더 크게 조사되었다. 이를 통해 습도를 높게 관리하여 미세수분입자의 양이 많고 또한 오래 공중에 머물게 하는 것이 가루이 방제에 더욱 효과적인 것으로 판단되었다. 3차 및 4차 실험에서 Neem Oil과 Oleic acid의 방제효과는 78%와 76.4%로, 분무만 했을 때의 53%보다 큰 효과를 나타내었다. 따라서 가루이 방제에 화학 살충제 대신에 이류체 포그시스템을 이용하여 두 가지 천연물을 사용하는 것이 매우 좋은 방법이며, 특히 저렴한 Oleic acid를 이용하는 것이 경제적인 것으로 사료된다. 또한 평소에 이류체 포그시스템으로 온도와 습도관리를 하다가, 약제방제시 이류체 포그시스템을 이용하는 것이 악성 노동력 감소, 환경친화성, 생산성 증대 등에 기여하는 방안이 될 것으로 사료된다.

This study was carried out to evaluate toxicities of two formulations (microemulsion, ME and wettable powder, WP) for acetamiprid+etofenprox against aphids (Aphis gossypii), thrips (Frankliniella occidentalis) on the cucumber greenhouse and whiteflies (Trialeurodes vaporariorum and Bemisia tabaci Qbiotype) on the tomato greenhouse. The activities of two formulations were evaluated by testing residual effect and toxicities against eggs, nymphs and adults of whiteflies in the laboratory, and control effect in the greenhouse against whiteflies, aphids and thrips. All trials were tested at the recommended concentration(RC) and a half concentration of RC of each formulation. In the laboratory trials against eggs and nymphs of whiteflies, the effect of ME was more effective than that of WP and showed more than 80% ovicidal activities, and 40%~60% larvicidal activities on the 3rd instars nymph of whiteflies at the recommended and its half concentrations. On the residual effect against the adults of the two whitefly species, WP formulation was more effective than ME and showed more than 70% mortality at the 5th day after treatments of recommended concentrations. In the field trials, the effects of ME against whiteflies and thrips were more excellent than those of WP. On the other hand, the effect of WP against aphids was more excellent. These results indicate that the formulation of insecticide can be played an important role in the control strategy of the pest in field.