• Title, Summary, Keyword: overwintering larval development

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Investigation of Biological Characteristics of Rice Stem Borer (Chilo suppressalis Walker) and Variation in its Occurrence Patterns Among Crops (작물별 이화명나방의 발생양상 변동과 생물적 특성 연구)

  • Choi, Nak Jung;Choi, June-Yeol;Lee, Bong-Choon;Kim, Sang-Min;Ra, Ji-Eun;Baik, Chai-Hun;Lee, Jong Jin
    • Journal of Environmental Science International
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    • v.26 no.1
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    • pp.47-54
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    • 2017
  • We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. This study aimed to understand how C. suppressalis damages crops and to utilize this basic data for the establishment of environment-friendly control methods like pheromone traps. This study surveyed the changes in occurrence patterns of C. suppressalis, biological characteristics of overwintering larvae, and the efficacy of different types of pheromone traps the years. We found similar occurrence patterns of C. suppressalis in different crops. In addition, occurrence time of the first generation was advanced. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. It was confirmed that larvae of C. suppressalis generally prefer the lower part of the stems of Miscanthus. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. However, it is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The major Miscanthus fields are generally located in the areas protected for sources of drinking water, owing to which spraying of chemical pesticides is very limited. The results of this study provide important inputs for the development of environment-friendly control methods.

Effects of Juvenile Hormone and Molting Hormone on Diapausing Adults of the Alder Leaf Beetle, Agelastica coerulea Baly (휴면중인 오리나무잎벌레 (Agelastica coerulea Baly) 성충에 미치는 유약호르몬과 탈피호르몬의 영향)

  • 최진우;부경생
    • Korean journal of applied entomology
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    • v.30 no.4
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    • pp.258-264
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    • 1991
  • Studies were carried out to investigate effects of temperature and photoperiod on diapause induction and of juvenile hormone III and 20-hydroxyecdysone treatment on diapausing adults of the alder leaf beetle, Agelastica coerulea Baly(Chrγsomelidae: Coleoptera). Its life cycle and ovarian development in adults were also observed. The beetle had one year life cycle with egg, larval, pupal and adult periods being 7-10, 19-21, 14-15 days and about 10 months, r respectively. All adults showed a diapause syndrome when the larvae were reared at $20^{\circ}C$ or $25^{\circ}C$ in combination of photoperiods of 16L/8D, 12L/12D, or 8L/16D. Their ovarioles did not s show any development of vitellogenesis before or during diapause and even when exposed at $15^{\circ}C$ after overwintering. When diapausing adults were treated with JH III they resumed feeding and laid several eggs and broke diapause condition temporally. But diapausing adults treated with 20-hydroxyecdysone did not show any response.

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Studies on the Regional Characteristics in Occurrence of the Rice Stem Borer, Chilo suppressalis Walker in Korea (한국에서 이화명나방(Chilo suppressalis Walker) 발생상의 지역적 특성에 관한 연구)

  • 박창규;현재선
    • Korean journal of applied entomology
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    • v.29 no.4
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    • pp.257-268
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    • 1990
  • The regional characteristics in the occurrence of the rice stem borer, Chilo suppressalis (Walker), in Korea, were examined by analyzing the light trap data obtained from 39 locations during the years of 1965-1988, and some ecological significance of the overwintering larval populations collected from the four locations where some of the typical ecological-race have been known, the results obtained are as follows; The total number of the moths have decreased greatly throughout the nation since 1970. The decrease in the total number of moths related with those in the spring moth but not in the summer moths, and suggested that the changes in the rice production systems have effected significantly on the second generation of the insect. The variations between the regions had been gret in 1960's, decreasing phase in 1970's and increasing phase in loast decade. The overall average of 50% emergence dates have shifted earlier in both moths, and the changes were different considerably with the regions as wheel as in generations. When the overwintered larvae were incubated at $25^{\circ}C$ and RH of 90%, the average mortalities were 21.07% for Suweon, 43.06% for Iri, 63.51% for Jinju, 27.04% for Gwangju. When the overwintered larvae were incubated at $25^{\circ}C$ and RH of 90%, the average mortalities were different with the body weight; 45.44% for the larvae of less than 39 mg, 37.61% for 40-49 mg, 37.28% for 50-59 mg, 30.17% for greater than 60 mg. When the overwintered larvae wee incubated at $25^{\circ}C$, post-diapause larval development periods of body weight classes were 18.6$\pm$1.2 days for the larvae of less than 39 mg, 20.4$\pm$3.3 days for 40-49 mg, 21.4$\pm$3.2 days for 50-59 mg, 21.8$\pm$3.2 days for grater than 60 mg, and only the larvae of less than 39 mg, body weight class less than 39 mg was found statistically different in post-diapause larval development periods. From these results, the changes in the cultural practice of the rice have effected on the ecological pattern of the rice stem borer, and the effects seemed to be different with the generations, and with the regions where the different ecological races are distributing.

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Population Phenology and an Early Season Adult Emergence model of Pumpkin Fruit Fly, Bactrocera depressa (Diptera: Tephritidae) (호박과실파리 발생생태 및 계절초기 성충우화시기 예찰 모형)

  • Kang, Taek-Jun;Jeon, Heung-Yong;Kim, Hyeong-Hwan;Yang, Chang-Yeol;Kim, Dong-Soon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.10 no.4
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    • pp.158-166
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    • 2008
  • The pumpkin fruit fly, Bactrocera depressa (Tephritidae: Diptera), is one of the most important pests in Cucurbitaceae plants. This study was conducted to investigate the basic ecology of B. depressa, and to develop a forecasting model for predicting the time of adult emergence in early season. In green pumpkin producing farms, the oviposition punctures caused by the oviposition of B. depressa occurred first between mid- and late July, peaked in late August, and then decreased in mid-September followed by disappearance of the symptoms in late September, during which oviposition activity of B. depressa is considered active. In full-ripened pumpkin producing farms, damaged fruits abruptly increased from early Auguest, because the decay of pumpkins caused by larval development began from that time. B. depressa produced a mean oviposition puncture of 2.2 per fruit and total 28.8-29.8 eggs per fruit. Adult emergence from overwintering pupae, which was monitored using a ground emergence trap, was first observed between mid- and late May, and peaked during late May to early June. The development times from overwintering pupae to adult emergence decreased with increasing temperature: 59.0 days at $15^{\circ}C$, 39.3 days at $20^{\circ}C$, 25.8 days at$25^{\circ}C$ and 21.4 days at $30^{\circ}C$. The pupae did not develop to adult at $35^{\circ}C$. The lower developmental threshold temperature was calculated as $6.8^{\circ}C$ by linear regression. The thermal constant was 482.3 degree-days. The non-linear model of Gaussian equation well explained the relationship between the development rate and temperature. The Weibull function provided a good fit for the distribution of development times of overwintering pupae. The predicted date of 50% adult emergence by a degree-day model showed one day deviation from the observed actual date. Also, the output estimated by rate summation model, which was consisted of the developmental model and the Weibull function, well pursued the actual pattern of cumulative frequency curve of B. depressa adult emergence. Consequently, it is expected that the present results could be used to establish the management strategy of B. depressa.

Host Range, Occurrence and Developmental Characteristics of Ceroplastes pseudoceriferus (Homoptera : Coccidae) on Persimmon Trees (감나무에 기생하는 뿔밀깍지벌레의 기주범위, 발생소장, 각 태별 생육 특성)

  • 박종대;박인선;김규진
    • Korean journal of applied entomology
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    • v.29 no.4
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    • pp.269-276
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    • 1990
  • This study investigated host range, seasonal occurrence and developmental characteristics of Ceroplastes pseudoceriferus Green on persimmon trees. The host plants covered 34 families and 66 species, including newly recorded species of Chenopodum album var. centrorubrum, Glycine max, Begonia semperflorens, Pharbitis nil, Perilla frutescens var. japonica and Erigeron canadensis. There was one generation of C. pseudoceriferus a year with larval stage expanding from mid-June to mid-October. Average number of eggs laid per female was 1,073$\pm$177.3. Hatching rate was 97.3% and was not affected by temperatures and photoperiods. Stadium varied as 23.4 days in eggs, 128.3 days in larvae and 213.3 days in female adults including overwintering periods at natural condition.

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