• Korean journal of applied entomology
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• v.36 no.1
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• pp.111-117
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• 1997

Occurrence status of Tetranychus viennensis Zacher was investigated in Kyonghuk province. Its ecological studies were carried out and chemical control efficacy against females and eggs was examined. And the results ohtained are as follows. T. viennensis occurred from mid April through mid November with the peak time in June on cherry tree. Population level of T. viennensis was varied from 0 to 160 individuals per 100 peach leaves in different peach orchards, and its occurrence rate was 35% out of 20 ochards. However no T. viennensis was observed from 25 apple orchards in 5 districts of Kyongbuk province. Overwintering stage of T. viennensis females appeared in mid October, and most of them moved into under the rough hark in early November. The overwintered adult females moved out from the rough bark to leaves in early April. Mortality during overwintering was about 55%. Under four constant temperatures of 16, 19, 22, 25$^{\circ}$C. egg periods were 14. 3, 9.2, 6.8, and 4.0 days ; larva -nymph periods were 20.2, 13.9, 8.7, and 6.6 days. Female longevity was 67. 7, 60.7, 46.4, and 34.0 days : mean tota: fecundities per female were 21.2, 44.3, 54.4, and 64.7 eggs. Some acaricides, azocyclotin, pyridaben, propargite, tehufenpyrad and fenpyroximate were highly effective against females, while hexythiazox and clofentezine showed very low control effect from 3.6 to 14.4%. Whereas, all of 7 acaricides tested highly effective against the eggs.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.283-289
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• 2013

This study was performed to investigate the biological characteristics of the brown lacewing Micromus angulatus (Stephens) at four different temperatures (15, 20, 25, and $30^{\circ}C$) and $70{\pm}10%$ relative humidity under a photoperiodic regime of 16:8(L:D) h. The developmental threshold and effective accumulative temperature from egg to pupa for M. angulatus were $9.6^{\circ}C$ and 270.3 day-degrees, respectively. The developmental period of egg, larva, and pupa at $25^{\circ}C$ was 4.4, 5.5, and 6.9 days. respectively. The longevity of an adult female M. angulatus was 34.9 days. The oviposition period for M. angulatus was 28.7 days, in which it laid a total number of 515.2 eggs during its life span. The maximum number of eggs laid by a female in a day was 54.8. Daily consumption by M. angulatus at $25^{\circ}C$ was 18.9 $1^{st}$ instars, 47.2 $2^{nd}$ instars, 57.7 $3^{rd}$ instars, and 91.0 adults of the glasshouse potato aphid, Aulacorthum solani. Therefore, M. angulatus could be a promising biological control agent against aphids.

• Korean journal of applied entomology
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• v.35 no.4
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• pp.302-308
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• 1996

This study was conducted to investigate occurrence and host ranges of Liriomyza trifolii Burgess, American serpentineleafminer, in Chonnam province. Also, temperature effects on the development along with morphologicalcharacteristics in each instar of L. trifolii were studied. L. hifolii was observed from 22 species inthe 7 families. Gerbera, chrysanthemum and tomato were the most damaged host plants. Egg was transparentwhite with lengthlwidth of 0.27 mm10.25 mm while matured larva was yellow with that of 2.03 mm10.80 mmrevealing serpentine gallary under leaf cuticle. Pupa was light brown with that of 1.75 mrn10.74 mm and pupatedon the soil and/or leaf surface. Lengthlwing span of adult was 1.78 mm/3.43 mm. Number of oviposition/sucking punches by L. bifolii adult was 26.1% and 13.3% in tomato and gerbera leaves respectively. Feedingactivity of larval stage was highest at 2OoC. Developmental~threshold (DT) and effective accumulative temperatures(ET) on gerbera leaves were 11.2"C, 33.9DD in egg, 10.3'C, 38.6DD in larva, 10.7"C, 152.3DD inpupa, and 10.8"C, 222.8DD from egg to pupa. On tomato leaves, DT and ET were 13.6"C, 20.2DD in egg, 9.3"C, 43.7DD in larva, ll.O$^{\circ}$C, 114.3DD in pupa, and 11.6"C 178.2DD from egg to pupaDD in pupa, and 11.6"C 178.2DD from egg to pupa pupa.

• Korean journal of applied entomology
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• v.37 no.1
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• pp.53-58
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• 1998

Comparative studies on some ecological characteristics of three phytoseiid mitespecies (one native; Arnblyseius womersleyi Schica, and two introduced species; A. fallacis Garmanand Typhlodromus occidentalis Nesbit) were carried out. The two-spotted spider mite (Tetranychusurticae Koch) was supplied as prey. Under four constant temperatures of 20, 23, 25 and 30f OS$^{\circ}$C,duration of growth from egg to adult for A. womer.vleyi was 11.5, 7.7, 6.7 and 5.6 days. While twoother species needed slightly shorter time but not significantly different. Critical temperature andeffective degree-days (DD) of A. womerslevi females were 83$^{\circ}$C and 1 1 1.6 DD, whereas those of A..fallacis were 10.7"C and 86.0 DD, and those of 7: occidentalis were 10.7"C and 94.1 DD. Also, thoseof males were similar to their females. Average longevity of females of A. womersleyi, A. fallucisand 7: occidentalis were 18.2 k 8.67, 19.6 3~7.18 and 13.0f5.66 days, total fecundity were 34.3 $-11.93, 39.8k 12.64 and 23.6k8.86, respectively. Under four constant temperatures of 20, 23, 25 and30-t0.S$^{\circ}$C, A. womersleyi consumed 9.1 f2.49, 9.7 k2.00, 9.7 f 2.61, and 10.3 k2.33 eggs of 7:urticae throughout their development. A. ,fizlluc~i.sc onsumed 10.2 k 2.52, 9.7 f2.29, 10.7 f 2.37 and10.1 k2.62 eggs, while, 7: occidentalis consumed 1 1.9 k3.43, 14.2 f4.50, 14.8 k 3.2 1 and 12.7 f2.95 eggs, respectively. Gravid females of A. womersleyi, A. f~zllacis and 7: occidentalis consumed11.4f1.59, 12.5k1.43 and 11.7k3.07 eggs, or consumed 11.9f 2.63, 12.4k3.82, and 12.5f 3.73protonymphs of 7: urticae in a day at 25-30$^{\circ}$C.e in a day at 25-30$^{\circ}$C.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.38-44
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• 1996

These experiments were conducted to investigate the ecological characteristics of Amblyseius womersleyi Schica,which was biological agent in the integrated management of tea red spider mite, Tetranychus kanzawai Kishida.At four constant temperatures of 15, 20, 25, and 30$^{\circ}$C, the periods of A. womersleyi from egg to adult emergencewere 22.8, 9.6, 4.8, and 3.6 days, respectively. Developmental threshold and effectively cumulative degree-day from egg to adult emergence were 12.7"C and 61.4DD, respectively. Preoviposition periods of A.womersleyi were shorter than oviposition and postoviposition periods. The number of eggs laid per female was21.7, 28.1, 34.2, and 48.0 at the respective temperatures. The intrinsic rates of increase were estimated to be 0.064, 0.139, 0.349, and 0.402; the mean generation times were 36.0, 19.3, 8.6, and 7.7 days; the populationdoubling times were 10.8, 5.0, 2.0, and 1.7 days, respectively. A. womersleyi overwintered on green weeds, fallenleaves and in the soil surface as adult females. A. womersleyi gravid female consumed 3.0, 4.9, 15.7, and19.4 eggs of T. kanzawai per day at 15, 20, 25, and 30$^{\circ}$C, respectively. A. womersleyi protonymph consumed4.6 eggs, deutonymph 6.3 eggs, and female during oviposition consumed 19.4 eggs, and 6.8 eggs of T. kanzawaiduring postoviposition per day at 30$^{\circ}$C. at 30$^{\circ}$C.

• Journal of Forest and Environmental Science
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• v.10 no.1
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• pp.32-37
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• 1994

This study was carried out to clarify the primary hosts of Tetrastichus sp. and its host relationship, development and reproductive capacity. Protopulvinaria mangiferae was parasitized by Aneristus ceroplastae, Microterys flavus, Coccophagus hawaiiensis. All of these primary parasitoid were attecked by the hyperparasite Tetrastichus sp.. Tetrastichus sp. was bound to be a solitary ectoparasite. Eggs were laid on the pupa of the primary host or attached to the inner surface of the integument of the scale insect. Threshold of the development and thermal constants for completion of immature stages were $9.8^{\circ}C$ and 272 day-degrees, respectively. At $25^{\circ}C$ the life span of both sexes without any food or with water were very short as compared with that with honey. After a pre-oviposition periods of about one day they laid on overage 220 eggs each, almost all during the first half of their life. The value of the net reproduction(Ro), the mean length of a generation(T) and the intrinsic rate of natural increase(r) were calculated as 99.6, 32days and 0.142 per female per day respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.4
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• pp.300-304
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• 1993

This experiment was carried out to increase the utility and productivity of forage crop as to investigate the rotation system which is suitable to cultivat at the alpine area. The treatments were 9 crops combinations including corn - rye treatment. The results obtained were as follows: 1. Rye can be cultivated satisfactorily at cold and high altitude areas such as Tae Kwan Ryong. 2. Corn, to be raised as a second crop after rye in the same year, does not have to be early (short) or medium maturity varieties in the high alpine area. 3. It is possible to increase the harvest by 30% in terms of dry melter or green crop yield through raising two crops, rye and corn, in the same year. 4. Maturity period or growth conditions of corn. as a tropical crop and the best forage crop, can improve or worsen acording to the external circumstance, such as low temperature resulting from high atitude.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.200-206
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• 1982

A computer simulation model was constructed to explore the phonology of the Striped Rice Borer, Chilo suppressalis (Walker), in Korea. The phenological system model based on the concept of distributed time delay was written in the computer program 'INSECT' and simulated with the estimated parameters of the effective day-degrees (DEL) and the order of time delay (K) for determining the validity of the system model. The accumulated emergence curves obtained from the phenological model were slightly different from the observed light trap data at the early and late stage of the moth emergence in 1978. The differences between observed and simulated $50\%$ emergence date were five to six days in the locations of Suweon and Chuncheon, while it was only two to three days in Iri, Daegu, Boseong, and Milyang. The phenological model should be further improved for simulation of field population changes by adding the information of the time delay process in each developmental stage, the age distribution of overwintered population, and the limiting factors of the borer mortality.

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.283-288
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• 2006

Characteristics of the rootstock formation and flower bud differentiation according to sowing time for production of the high quality rootstock in Chicory (Cichorium intybus L.) was investigated. The flower bud initiation was on the 17th of July after sowing in April, the 2nd of July after sowing in May, the 30th of July after sowing in June and the 1st of October after sowing in July. But they didn't differentiate after sowing in August and September. The days required from germination to flower bud initiation and accumulated temperature depended on the weather. If the outside air temperature was high, the days required were less, If the outside air temperature was low, the days required were greater, the accumulated temperature was similar to the days required in this experement, too. The rootstock sown from April to July wasn't good enough to be use because the flower bud differentiation was generated before harvestable weight. the weight of rootstock was sown in September wasn't heavy enough in weight because the outside air temperature was too low for it to grow well. The plant grows slow and steady through out winter. The rootstock sown in August was havestable 200g in 90 days after sowing before the flower bud differentiated. The best sowing time for the production of high quality rootstock of Chico in the climate of Korea is researched to be August.

• Korean Journal of Ichthyology
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• v.5 no.1
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• pp.53-67
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• 1993

In December of 1989 and 1990, matured adults of chum salmon were collected from Namdae-chun River in Yangyang-gun, Kangwon-do, Korea. Artificial insemination was made at captured locations. The fertilized eggs were hatched in trough incubators and the larvae were reared in laboratories of the Yangyang Fisheries Institute and the Korea Ocean Research and Development Institute. The fertilized eggs of this species were demersal and separated, and red in color with mean diameter of 7.2mm. The hatching took place from 480 to 531 degree($^{\circ}C$) days after fertilization. The newly hatched alevins were 1.80 to 2.56cm in total length with big yolk and lied on the bottom. In 35 days after hatching, the alevin attained $3.56{\pm}0.12cm$ in total length, and absorbed the yolk completely to become fry with 7 to 11 parr marks on the body. In 3 months after hatching, and the fries became smolt with silvery scales haring 5.67-6.53cm in total length. The early larval developments of chum salmon could be divided into three stages according to the changes in body shapes and length : larval stage before swim up, swim up stage and smolt stage. The growth of snout, trunk and body height to total length were faster than other body parts in swim up stage.