• Korean journal of applied entomology
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• v.49 no.2
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• pp.129-137
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• 2010

Four major agricultural insect pests, Bemisia tabaci, Myzus persicae, Plutella xylostella and Tetranychus urticae, were irradiated with 30, 50, 70, or 100 Gy electron-beam. Longevity, egg hatching, emergence, and fecundity of the test insects were measured. Hatchability of B. tabaci, P. xylostella and T. urticae declined with increasing irradiation doses, and all B. tabaci and T. urticae eggs were dead at 100 Gy. When eggs of B. tabaci, P. xylostella and T. urticae were irradiated, hatch was inhibited. B. tabaci adults grown from 70 Gy irradiated eggs did not lay eggs. Fecundity of P. xylostella from the 100 Gy irradiated eggs decreased. When B. tabaci, P. xylostella, M. persicae and T. urticae nymphs/larvae were irradiated, the results were similar as those of the hatched eggs. When P. xylostella pupae were irradiated with 100 Gy, fecundity of emerged adults decreased and no eggs hatched. When B. tabaci, P. xylostella, M. persicae and T. urticae adults were irradiated with 70 and 100 Gy, fecundity decreased and egg hatch of B. tabaci was inhibited. However, the longevity of adults did not change and electron-beam irradiation of all developmental stages had no effect on the longevity of adults.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.269-274
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• 2006

Temperature-dependent development studies of two aphid species, A. egomae and A. gossypii occurring in green perilla greenhouse were conducted at $15{\sim}35^{\circ}C$, and 16:8 (L:D h) of light period in the laboratory. The mortality of two aphid species was high in young stages (1st and 2nd). In A. egomae, the mortalitiy increased with increasing and decreasing temperature: the mortalitie at $15^{\circ}C$ and $35^{\circ}C$ were 22.3% and 15.6%, respectively. While the mortalities of A. gossypii increased with increasing temperature: the mortality at $35^{\circ}C$ was 50.0%. The developmental periods of A. egomae and A. gossypii ranged from 20.8days to 5.4days and from 22.6days to 9.1days at $15^{\circ}C$ to $30^{\circ}C$ of temperature resion, respectively, and were 7.2days and 10.7days at $35^{\circ}C$ for each species. The lower developmental threshold temperatures for total nymphs of A. egoame and A. gossypii were $9.9^{\circ}C$ and $4.9^{\circ}C$, respectively and an effective degree-days (DD) for the developmental completion of total nymph were 108.0 DD for.A. egomae and 221.2DD for A. gossypii. In green perilla greenhouse, the occurrence period of A. gossypii was earlier about 15 days than that of A. egomae. When the occurrence period of two aphid species was estimated by degree-days based on lower threshold temperatures, A. gossypii occurred earlier than A. egomae in the field. A. gossypii occurred from early April and showed dominant position to late May compared with A. egomae Whereas, A egomae started to occur from mid April and then were abundant after late May followed by abrupt population crash around late July.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.277-282
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• 2005

This study was conducted to investigate morphological characteristics and effects of temperature on the development of Piezodorus hybneri on soybean. The unibanded stink bug, Piezodorus hybneri, is a serious insect pest in soybean fields giving damage to seeds in pod and leaves of soybean lowering both quality and yield. Eggs were spherical and laid in two raws on the leaves and pods of soybean plants. Body lengths of females and males were 9.8 mm and 8.7 mm, respectively. Egg hatch rates were better in higher temperature within the range of examined temperatures, which ranged in $81.2{sim}93.2%$. The development periods of eggs at the temperatures of 20, 25, 30 and $35^{\circ}C$ were 10.7, 5.0, 4.0, and 3.0 days, respectively. Mean developmental periods of 1st, 2nd, 3rd, 4th and 5th nymphs at $25^{\circ}C$ were 3.2, 3.4, 3.4, 3.3 and 5.9 days, respectively. Development threshold and effective accumulative temperature were $13.3^{\circ}C$ and 65.5 DD (day degree) for egg stage, $9.9^{\circ}C$ and 322.8 DD for nymph stage, $10.7^{\circ}C$ and 386.4 DD from egg to adult, respectively. Oviposition began from 10 days after emergence at $25^{\circ}C$, and the longevity of female and male were 52.5 and 38.2 days, respectively. Total number of eggs and egg masses laid by a female at $25^{\circ}C$ were 496 and 21.3, respectively, The longevity of adult female was shortened with increasing temperature, whereas the total numbers of eggs laid by a female were decreased.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.175-183
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• 2021

As a baseline study of (common name) Locusta migratoria (Orthoptera: Acrididae) to utilize as a food source, we investigated the developmental characteristics of ovaries and eggs. Locusta migratoria had a pair of ovaries and more than 90-104 panoistic ovarioles. The ovary length in the adult stage was longer than it is in the 5th nymph stage. The length on the first day of the adult stage was 2.5-fold longer than the first day of 5^th instar. The ovary length showed a tendency to increase until the 30th day of the adult phase, but decreased from the 35^th day. Ovarioles length was about half of the ovary length, showing a similar tendency to the variation of ovary length. The lengths of the ovaries and the ovarioles increased proportionally to body weight. The matured eggs were identifiable from the 15^th day of the adult stage, and the number was the highest on the 30^th day at 50.6 individuals. Spermatheca size was also affected by the ovary development. The ovaries of L. migratoria were highly matured until the 30th day of adult stage. Weight and size of eggs increased sharply from the 4th day after egg oviposition and remained from the 7th day after spawning. Based on the above results, we found that the ovary of L. migratoria was most developed on the 30th day of adult phase, and 1st nymph is being hatched on the 10th day of the oviposition.

• Korean journal of applied entomology
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• v.12 no.2
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• pp.83-87
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• 1973

Experiment was conducted to study resistance of rice varieties and lines originated from Korea and IRRI sources to the zigzag-striped leafhopper, Recilia (Inazuma) dorsalis MOTSCHULSKY The nature of varietal resistance to the insect was evaluated from the viewpoints of feeding and ovipositional preferences and antibiosis. The varieties Su-Yai-20, Muthumanikam, PTB-18 and Vellanlangalayan were resistant and DV-139 moderately resistant to tile zigzag-striped leafhopper, and the other varieties tested were susceptible. Feeding and ovipositional preferences were significantly different among the varieties, but no correlation was observed between the two preferences. The nature of resistance of rice to the insect seemed to be related with The non-feeding preference, not non-ovipositional preference. The resistant (Vellanlangalyan and Su-Yai 20) and moderately resistant(DV-139) varieties had high antibiosis against the zigzag-striped leafhopper.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.166-171
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• 1997

To find out an alternative prey of Orius strigicollis Poppius in the laboratory continuous rearing system, cotton aphid (Aphis gossypii), two spotted spider mite (Tetmnychus urticae) and mold mite (Tyrophagus putrescenriae) were tested as alternative prey. Development and oviposition of 0. strigicollis were observed at 25f l0C, RH 60-80% and 16L:8D. Survival rate and developmental period of the nymphal stages of 0. strigicollis was 81. 6% and 11.6 days when fed on cotton aphid, 56.796, 14.6 days, 42.3% and 16.5 days when fed on two spotted spider mite and mold mite, respectively. Total oviposition of 0. strigicollis was 68.5 eggslfemaie fed on cotton aphid, 46.1 and 26.5 eggsifemale fed on two spotted spider mite and mold mite, respectively. Cotton aphid seems to be most suitable prey for rearing 0 . strigicollis among the three prey species tested.

• Korean journal of applied entomology
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• v.57 no.2
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• pp.77-85
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• 2018

We surveyed 281 sites of tropical plants and 666 sites of fruit plants for three years (2015~2017) on Pseudococcus longispinus and Pseudococcus orchidicola which have not been surveyed domestically. In tropical plants, P. longispinus were found at 34 sites, while P. orchidicola were found at 87 sites. However, both species were not found in fruit plants. The developmental characteristics of P. longispinus and P. orchidicola were investigated under various temperatures. The female nymph of P. longispinus did not develop at $14^{\circ}C$ and the developmental period was the longest at $16^{\circ}C$ for 361.4 days and the shortest at $32^{\circ}C$ for 39.0 days. The longevity of female adult of P. longispinus was the shortest at $28^{\circ}C$ as 71.7 days. The number of offspring was highest at 177.7 at $32^{\circ}C$. The female nymph of P. orchidicola did not develop at $12^{\circ}C$. However, the developmental period was the longest at $14^{\circ}C$ for 184.9 days and the shortest at $28^{\circ}C$ for 21.5 days. The longevity of female adult of P. orchidicola was the shortest at 51.5 days at $28^{\circ}C$. The number of offspring was highest at 143.8 at $28^{\circ}C$. The net reproductive rate ($R_0$) and intrinsic rate of increase ($r_m$) of P. longispinus were 162.3 and 0.127 at $32^{\circ}C$, respectively. The $R_0$ and $r_m$ of P. orchidicola were 98.3 and 0.139 at $28^{\circ}C$, respectively. These results suggest that the optimum temperature of P. longispinus and P. orchidicola was $32^{\circ}C$ and $28^{\circ}C$, respectively. Therefore, we guess that they can never be able to survive the winter of Korea.

• Korean journal of applied entomology
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• v.38 no.2
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• pp.117-121
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• 1999

Development and reproduction of the sycamore lace bug, Corythucha ciliata, were investigated under different temperature regimes. Duration of development from egg to pre-adult of the sycamore lace bug measured seven temperatures ranged from 54.0 days at 18$^{\circ}$C to 17.9 days at 33$^{\circ}$C. Development was not successful at 15$^{\circ}$C and 35$^{\circ}$C. Developmental zero point and total effective temperature for development of egg, nymphal, and complete development were 1 1 .O, 10.9, ll.l$^{\circ}$C and 150.3, 230.6, 376.1 degree-days, respectively. Longevities of adult females varied to temperature from 51.8 days at 18$^{\circ}$C to 17.2 days at 33$^{\circ}$C. The average fecundity per female was greater at 25$^{\circ}$C and 28$^{\circ}$C compared with at other temperatures. The intrinsic rate of natural increase (r,) and net reproduction rate (R,) were highest at 28$^{\circ}$C as 0.170 and 73.25, respectively. As a result, optimum ranges of temperature for C. ciliata growth were between 25$^{\circ}$C and 28$^{\circ}$C.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.321-327
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• 1995

This study was conducted to determine the winter ecology of the small brown planthopper (SBPH), laodelphax striatellus Fallen, in Milyang, east Kyungsangnamdo province. The age distribution in the overwintering SBPH population varied according to collection dates. In early December, the population distribution was 60% 4th instar, 30% 3rd instar, 6% 5th instar, 3.4% 2nd instar with very few adults and 1st instar. In early March 5th instars had the highest propotion (47-50%) with 4th instar 44-46%. In early April the adult population was 75-81% of the population. The averaged nymphal instar converted the age distribution of he overwintering SBPH in to the into the numerical values tended to increase continuously. However, there were some differences in the averaged nymphal instar of overwintering SBPH annually and these differences resulted from different age distribution of the overwintering SBPH due to different annual temperature fluctuations during overwitering periods. The weight of the overwintering SBPH increased continuously during overwintering periods. The collection density of the overwintering SBPH population was significantly higher on the levee than in the barley field. Percent nymphal parasitism by haplogonatopus atratus in the overwintering SBPH population averaged about 21% regardless of overwintering years.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.193-198
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• 1998

Experiments were conducted to investigate the population fluctuation, developmental periods, fecundity, hatching rate and demage of Citrus red mite (Panonychus citri M.) on Yuzu trees (citrus junos T.) from 1996 to 1997. Citrus red mite occurred from May to November and made two peaks. The first peak was in July to August and the secondary peak was in October. Density of the second peak was higher (9.5 miteslleaf) than that of the first peak. In the constitution rate of each developmental stage of citrus red mite on Yuzu leaves, egg stage occupied 85%. At the four constant temperature (15, 20, 25, 30 + 1$^{\circ}$C, RH 60 + lo%, 14L- IOD) conditions, the developmental period from egg to adult was 41 .l, 15.5, 11.0 and 9.4 days ; Mean longevity of adult was 23.3, 8.3, 6.3, and 6.1 days; Mean number of egg laid per female per day was 1.6, 3.2, 4.5, 4.0 eggs; Mean hatching rate was 66.6, 85.7, 90.7 and 94.7% at above temperature, respectively. When sprayed acaricide at different density of Citrus red mite, the growth of young Yuzu tree were better at low density. Defoliation rate during winter was 13.5, 20.6, 53.1, 72.6% at 4 control density 1 , 3, 6 mites per leaf and uncontrolled (10 ( ). When every time spray acaricide under 3 mites per leaf, defoliation rate during winter suppressed above 50% compare to uncontrol 72.6%.