Byeong-Ryeol Choi

Effects of a Mungbean Cultivar, Jangannogdu on Nymphal Development, Adult Longevity and Oviposition of Soybean Stink Bugs

Nymphal development, adult longevity, and oviposition of six different species of stink bugs were compared on seeds of a soybean cultivar, Taekwangkong, and two mung bean cultivars, Kyungseonnogdu and Jangannogdu in the insect rearing room (, 16L:8D). Nymphs of six species of stink bugs normally developed on Taekwangkong seed. While nymphs of Riptortus clavatus, Halyomorpha halys, and Dolycoris baccarum developed on seeds of Kyungseonnogdu and Jangannogdu normally, all nymphs of Plautia stali, Piezodorus hybneri and Nezara antennata died after 4th instars on Kyungseonnogdu and after 3rd instars on Jangannogdu. Each instar period tended to be increased as nymphal stages were progressed. Nymphal period was shortest on Taekwangkong seed, followed by Kyungseonnogdu and Jangannogdu, irrelevant to stink bugs species. Emergence rate, adult longevity, and preoviposition period of 6 stink bugs were different depending on the reared seeds. Of 6 different species examined, Riptortus clavatus, Halyomorpha halys, and Dolycoris baccarum which fed on Jangannodu did not emerge, Plautia stali, Piezodorus hybneri, and Nezara antennata which fed on Jangannodu did not oviposit.

Evaluation of Low Toxic and Residual Toxicity of Pesticides Registrated on Sweet Pepper Greenhouse to Orius strigicollis

For the development of integrated pest management system by harmonizing biological and chemical control, some experiments were carried out to select low toxic pesticides and to evaluate residual toxicity to natural enemies. Leaf dipping method and body dipping method were set up for evaluating toxicity to minute pirate bug, Orius strigicollis adult. We had tested 52 kinds of pesticides (33 insecticides, 19 fungicides) commonly used to control greenhouse insects, mites, and disease pests to natural enemies at the recommended concentration. Fourteen insecticides by body dipping method, 12 insecticides by leaf dipping method and 19 fungicides were selected as low toxic pesticides to O. strigicollis adult. After insecticide spraying at recommending dose on the sweet pepper plant, we examined residual effect of insecticides by introducing natural enemies on different days. Safety interval for introduction of O. strigicollis adult was established according to residual toxicity of pesticides. Safety insecticides at one day after treatment were pyraclofos, methomyl, thiodicarb, esfenvalerate bifenthrin, alpha-cypermethrin, etofenprox, fenvalerate, imidacloprid, acetamiprid, abamectin, emamectin benzoate, spinosad, indoxacarb. However, residual toxicity of nee-nicotinoids last up to 21 days to O. strigicollis adults.

Effects of Temperature on the Development and Longevity of the Gray Field Slug, Deroceras reticulatum Müller (Stylommatophora: Limacidae)

The egg size and weight of the gray field slug, Deroceras reticulatum Muller, was mm and 3.3 mg at , respectively. Its weight increased from newly laid eggs to adults for 17 weeks at four temperature regimes and was heaviest at , followed by 24, 16 and . Likewise, hatching rate of the egg batches was highest with 95% at , followed by 24, 16 and with significant differences. The number of eggs in the batches was increased with 20 at while it was only 10 at . The average accumulated egg-laying days was longest with 15 days at while shortest with 9 days at . The range of egg-laying period was shortest with 84-134 days at and longest at . Thus, the total number of eggs laid by adult D. reticulatum was highest with 217 at and lowest with 105 at . The egg period was 12-19 days while the juvenile period and adult longevity were 51-68 days and 85-134 days, respectively. The life span of D. reticulatum from egg to adult was longest with 216 days at , followed by 193 days at , 170 days at and 151 days at . Accordingly, the most favorable temperature for the oviposition, development and longevity of D. reticulatum is .

Damage analysis and Control threshold of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) on Greenhouse Eggplant and Sweet pepper

Cage experiments by artificial infestations with different initial densities of Frankliniella occidentalis were conducted to analyze damages and develop control thresholds of F. occidentalis on greenhouse eggplant in 2005 and on greenhouse sweet pepper in 2007. In the eggplant experiment, the infestations of F. occidentalis resulted in direct damage on fruit surface and non-marketable fruits which had several thin or thick lines or bleaching patches on the surface. F. occidentalis adults were frequently found on the flowers of eggplants, while nymphs were mainly observed on leaves. The fruit yield of eggplants was not significantly different among experimental plots with different initial density of F. occidentalis. Relationship between % non-marketable fruits among harvested fruits of eggplant and sticky trap catches of F. occidentalis (no. thrips/trap/week) at two weeks before the harvest showed a positive correlation. Using the estimated relationship, the control threshold of F. occidentalis on greenhouse eggplant was estimated at 10 adults per week at two weeks before the harvest when 5% of non-marketable fruit was applied for the gain threshold. In the experiment of sweet pepper, the direct damage by F. occidentalis was observed on the fruit surface and calyx, and the marketable grade of the damaged fruits decreased. The significant yield loss of marketable fruits was found in plots with high initial introduced-densities. There was a high relationship between thrips density and percentage of damaged fruits. Assuming 5% yield loss (non-marketable fruit) for the gain threshold, the control threshold of F. occidentalis on greenhouse sweet pepper was 4.8 adults per trap and 0.9 individuals per flower at two weeks before harvest.

Bacterial Stripe of Proso Millet Caused by Acidovorax avenae subsp. avenae in Korea

Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea(Received on February 23, 2012; Revised on August 9, 2012; Accepted on August 10, 2012)In July, 2009, proso millet (Panicum miliaceum), which showing the bacterial brown stripes on leaf sheaths,was collected in Miryang in Korea. Symptoms were systemic brown necrotic stripe lesions on the leaf sheathsand stems, and these symptoms were found in the entire field. The causal agent isolated from symptomaticplants was identified as an Acidovorax avenae subsp. avenae, based on its biochemical and physiologicalcharacteristics and also confirmed by the Biolog data and 16S rRNA gene sequence analysis. Also it causedhypersensitive response (HR) when it was inoculated onto the tobacco and tomato. It caused similarsymptoms when inoculated onto proso millet. This is the first report of A. avenae subsp. avenae, the causalagent of bacterial brown stripe of the proso millet in Korea. Keywords : Acidovorax avenae, Bacterial stripe, Panicum miliaceum기장(Panicum miliaceum L.)은 아프리카, 아시아, 남미에서 널리 이용되는 식량작물로 이들 지역의 단백질 공급에 기여하고 있다(Park 등, 2009). 또한 비타민, 무기질및 식이섬유 등의 기능성 성분의 함량이 높고 다양한 생리활성 물질이 많이 함유되어 있어 건강을 유지시키는 보조식량으로서의 역할이 중요시되고 있다(Ko 등, 2011). Acidovorax avenae subsp. avenae는 1909년 미국 오하이오 지역에서 귀리의 잎마름을 일으키는 식물병원세균으로 Manns(1909)에 의해 처음 보고된 후 벼 세균성줄무늬병(Goto, 1964; Kadota, 1996; Shakya 등, 1985), 옥수수의 세균성 줄기부패병(Rosen, 1926; Summer와 Schaad,1977), 조의 갈색줄무늬병(Rosen, 1926), 사탕수수와 기장의 붉은줄무늬병(Martin과 Wismer, 1989)을 일으키는 것으로 보고되었다. 국내에서는 벼 세균성줄무늬병(Shakya,1980)과 옥수수 줄기썩음병(Lee, 1991)이 보고되어 있으나, 기장에서는 아직 보고된 바 없다.본 연구는 국내에서 기장에 새롭게 발생한 세균성줄무늬병의 병징 및 병원세균의 균학적 특성을 보고하고자 한다.

Host Preference of Gray Field Slug, Deroceras reticulatum Müller, and Its Development and Longevity on Host Plants

This study was conducted to investigate food preference and developmental characteristics of the gray field slug, Mller (Stylommatophora: Limacidae) using various foods. The food preference of was most highest on Chinese cabbage ( L., followed on cucumber ( L.), and significantly low on beet ( var. Ruba), kale( L. var. D.C), carrot (Daucus carota L.) and Chinese cabbage ( L.) which were not different significantly. The total number of eggs laid by was the highest (n

The Species of Land Snails (Stylommatophora) on Leaf Perilla under Greenhouse in Geoyngnam Areas

The species of land snails (Stylommatophora) that feed on perilla plants were observed under leaf perilla greenhouses cultivated in the Milyang and Busan areas. Four species of land snails were recorded. Among them, three species were slugs, Meghimatium bilineatum in Phlomycidae, Deroceras reticula tum, and Limax marginatus in Limacidae, and one species was the snail Acusta despecta sieboldiana in Bradybaenidae. D. reticulatum occurred most frequently followed by A. despecta sieboldiana, L. marginatus and M bilineatum. Annually, land snails showed two peaks in the middle of April and in late November for D. reticulatum, early May to middle November for A. despecta sieboldiana, and middle April and early November for L. marginatus. M bilineatum, however, did not show any clear peak because of its low population occurrence.

Selection of Low Toxic Pesticides and Residual Toxicity to Cotesia glomerata

For the development of integrated pest management system by harmonizing biological and chemical control, some experiments wee carried out to select low toxic pesticides against natural enemies. and their residual toxicity were evaluated. Leaf dipping method, body dipping method, and diet treatment method were set up for the toxicity evaluation against Cotesia glomerata adults. We had tested 46 different pesticides (31 insecticides, 11 fungicides, 4 herbicides) at recommending concentration commonly used to control diamond back moth, disease and up-land weeds in chinese cabbage field. Twenty three insecticides, eleven fungicides, and four herbicides were shown to be low toxic to C. glomerata adults in the treatment of body dipping. After insecticide spraying at recommending dose on the chinese cabbage, we examined residual effect of insecticides by introducing natural enemies on different days. Safety interval for the introduction of C. glomerata adults was established according to the residual toxicity of pesticides. Safe insecticides for the introduction of C. glomerata adults at one day after treatment (DAT) were thiacloprid, acephate, chlorfenapyr, clothianidin and at 3 DAT were imidacloprid, deltamethrin, thiamethoxam, dimethylvinphos, emamectin benzoate.