• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.112-119
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• 1986

The variations of antibiosis to whitebacked planthopper (Sogatella furcifera Horvath) in resistant varieties, N 22 (Wbph 1) and ARC 10239 (Wbph 2) was investigated at different seedling ages and different tillers within a plant. The antibiosis of the rice plants to the insect was measured as the nymphal survival rate on the rice plants. The survival rate of the WBPH on N 22 was greater than on ARC 10239. It was also different at different seedling ages and the tillers within a plant with different tendency of two resistant rice genotypes, N 22 and ARC 10239. NO significant differences of nymphal survival rate was found between 7 and 30 days old seedlings on N 22, and greatly reduced on the 60 days old seedling. On the other hand it was increased up to on 30 days old seedlings and gradually decreased from on 40 days old seedlings of ARC 10239. The nymphal survival rate was greater in tillers than in the main culm of the rice plants.

• Life and Agrochemicals
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• s.257
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• pp.26-29
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• 2010

5월 중순부터 알에서 부화약충이 부화하기 시작하는데 꽃매미의 약충과 성충은 방제전용약제를 안전사용기준을 준수하여 살포하면 효과적으로 방제할 수 있다.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.363-380
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• 2019

Previous studies on the host plant range of Metcalfa pruinosa were conducted without distinguishing between its stages of development. In this study, we investigated host plants by studying the nymph and adult development stages of M. pruinosa. M. pruinosa nymphs were found on host plants that belong to 78 families and 227 species, and, to the best of our knowledge, host plants that belong to 27 families and 38 species have been reported for the first time. The host plants were divided into woody and herbaceous at the nymph stage of M. pruinosa, and the nymphs were found in 110 herbaceous and 117 woody species. M. pruinosa adults were found on host plants that belong to 87 families and 233 species, and, host plants that belong to 26 families and 36 species have been reported for the first time. The host plants were divided into woody and herbaceous at the adult stage of M. pruinosa, and the adults were found in 105 herbaceous and 128 woody species. Therefore, the total domestic host plant of M. pruinosa was 98 families 345 species. The nymph and adult in preoviposition stage prefer Helianthus annuus and the adult in oviposition stage prefer Persicaria tinctoria and Rosa rugosa.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.165-169
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• 1990

A study was carried out to investigate some biological characteristics of Pseudogonatopus nudas, a nymphal parasitoid of the whitebacked planthopper (WBPH) under laboratory conditions (26-$28^{\circ}C$). Developmental periods of eggs, larva, prepupa and pupa were 2.5, 7.8, 2.7, and 14.2 days in average, respectively. Total developmental period from egg to adult emergence was average of 27.2 days. More than 83.5% of the wasps emerged in the morning between 6 and 10 o'clock, while very few emerged in the afternoon. The average longevity of female and male were 11.8 and 3.4 days when honey and WBPH nymphs were supplied as food. female laid an average of 25.3 eggs and the oviposition period was 5.4 days. The parasitoid seemed to prefer the 3rd instar nymphas as the host for oviposition with 68.8%, followed by the 2nd (19.6%), 4th (11.05) and 5th instar (0.6%). And no parasitism was recorded from the 1st instar nymphs and in adults.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.492-495
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• 1992

Life cycle of the mirid predator, Cyrtorhinus lividipennis, was observed on the constant temper¬ature. Egg periods were 14.43, 9.33 and 6.94 days at $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$, respectively. Nymph periods were 24.3, 14.42, and 11.90 days at $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$, respectively and fe¬male longevity was 11.20, 11.93 and 11.87 days at above temperatures. Relationships between constant temperature and the developmental velocity of egg, nymph and egg-nymph were lin¬ear over temperatures tested. The calculated threshold temperatures of development were $10.7^{\circ}C$ in egg, $9.8^{\circ}C$ in nymph and $10.2^{\circ}C$ in egg-nymph. Total effective day-degrees were 133.9 in egg, 235.8 in nymph and 368.0 in egg-nymph. Number of eggs laid was 26.0 and 22.4 at $24^{\circ}C$ and $30^{\circ}C$, respectively.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.361-365
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• 2003

Several species of planthoppers such as brown planthopper, N. lugens (Stal) (BPH), smaller brown planthopper, Laodelphax striatellus (Fall n) (SBPH), and white-backed planthopper, Sogatella furcifera (Horv th) (WBPH) are distributed in Korean rice paddies but not easy to discriminate them in situ. Accurate discrimination of them is an indispensable process in the forecasting for their outbreak and control. Especially, innovative discrimination method for BPH was required because BPH was one of the most important insect pest of rice. Nymphs and adults of BPHs, SBPHS, and WBPHS, thus, were examined their morphological characteristics in the paddies and laboratory. The nymphs of BPH had different characters from those of SBPH and WBPH. The nymphs of BPH had white fluorescent spot between bottom of compound eye and antenna, while there was no that spot the other two species. The white spot was the brightest at the nymphs just after hatching and getting weaker as the nymph developed. At last the white spot was totally disappeared at the adult stage. This white spot was innovative criterium to discriminate nymphs of BPH, SBPH, and WBPH in rice paddies.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.231-235
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• 2005

This study was conducted to obtain the optimal spray time for Pseudaulacaspis prunicota (Maskell) (Homoptera: Diaspididae) in early seaon in Jeju. Oviposition time of overwintered females and activity of hatched nymphs of P. prunicola were monitored, and the phenology data were compared with the outputs estimated by a degree-days model of P. pentagona (Targioni-Tozzetti)). Overwintered females of P. prunicola began to lay eggs from mid to late April, and the eggs started to hatch from early May followed by the active migration of the hatched nymphs during mid May. The phenological events of P. prunicola in early season were likely comparable with those of P. pentagona reported in southern Korea and in central Japan. A degree-day model, which predicts the proportion of >50% hatched egg batches of P. pentagona (y=1[exp(-(-a+bx))]; y, proportion; x, degree-days based on $10.5^{\circ}C$ from 1 January; a=-18.80 and b=0.073), accurately described the migration time of P. prunicola hatched nymphs. Thus, it is considered that the degree-day model can be used for predicting the optimal spray time for P. prunicola in early season.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.116-118
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• 1984

This study was carried out to know the percentage of parasitism and host preference of Haplogonatopus atratus (Dryinidae) in the nymphs of small brown planthopper. The percentages of parasitism in the nymphal stage of planthopper at each generation were $19.2\%$ for overwinterd generation, $10.8\%$ for the 1st generation on barley field and $21.5\%$ for the 2nd generation on paddy field, respectively. The percents of the parasitism for the respective instars were $78.2\%$(3rd), $17.5\%$(End), and $4.2\%$(4th) when various developmental stages of the planthopper had been caged together. No parasitized individual was found for the instars of the 1st, the 5th and the adult.

• Korean Journal Plant Pathology
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• v.2 no.1
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• pp.17-21
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• 1986

The viruliferous vectors of the rice dwarf virus, nymphs of Nephotettix cincticeps did not overwinter in Uljin, although the disease occurred in fields. When considered the relationship between seasonal changes of vector and disease occurrence, there were 5 and 3 peaks in a year in occurrence of vector and disease, respectively. The over­wintered adults and the nymphs of the 2nd and 3rd generation served as the major transmittor of the. virus. In a field where the disease has been a problem for years, the ratoon hills rice cultivar Milyang No. 30 was infected $22.4\~26.8\%$ with the rice dwarf virus. When nonviruliferous nymphs were fed on the infected ratoon hills for 11 to 30 days, viruliferous nymphs overwintered, increased to $13.0\~18.2\%$. The winter barley infected with rice dwarf virus did not survive in winter, suggesting that infected barley may not serve as a inoculum source.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.311-318
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• 2009

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 ($28{\pm}2^{\circ}C$, 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.