• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.263-266
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• 2011

Crop protection strategies in organic horticulture aim to prevent insect pest and plant disease problems through utilization of non-chemical based control means. In order to develop a model for management of plant diseases and insects in organic cucumber cultivation, we compared efficacies between chemical pesticide spraying system and biological control means in semi-forcing and retarding cucumber cultivation during 2005 and 2006. Conventional chemical spray program using various chemical pesticides was applied 5 - 10 days intervals, while two different non-chemical pesticide application programs using two formulated biopesticides Topseed$^{TM}$ and Q-fect$^{TM}$, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 1) and using egg-yolk and cooking oil(EYCO), Bordeaux mixture, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 2) were applied 5 - 7 days intervals during entire cucumber cultivation period. Efficacy of both biocontrol agents programs was effective to comparable to conventional chemical pesitice spray program to control plant diseases such as powdery mildew and downy mildew as well as insect pests such as aphids and thrips which are known as major threats in cucumber organic cultivation. In this study, we established and evaluated an effective and economic crop protection strategy using various biological resources can be used to control plant diseases and pests simultaneously in organic cucumber cultivation field.

• Journal of Aquaculture
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• v.13 no.1
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• pp.69-78
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• 2000

Bioactivity growth and survival rte of yolk sac larvae in cultured black seabream (Acanthopogrus schlegeli) red seabream (Pagrus major) and olive flounder (Paralichthys olivaceus) to 5 different concentration (0, 25, 50, 75 and 100%) of water soluble fraction (WSF) of Kuwait crude oil were studied. The 75% and 100% of WSF concentration influenced negatively on the length growth of larvae in each species so the growth rates of total length in the concentration of WSF were significantly lower than those of control. The high concentration (50%, 75%, and 100%) of WSF influenced negatively not only on the swimming frequency and speed but also on the morphological abnormality of larvae. Red seabream larvae showed the highest rate of abnormality by WSF among the tested fishes. The fish larvae exposed during pre-and post-hatch (egg and larval stages) and during post-hatch (larval stage only) to the WSF were significantly influenced on their survival rate. The larvae of red seabream were more sensitive to WSF than those of black seabream and olive flounder. The survival rates of larvae exposed to higher concentration (50%, 75%, and 100%) of WSF were significantly lower than those of the control but those of the 25% group were not.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.343-349
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• 2007

Embryonic and larval developments on Pacific cod, Gadus macrocephalus are described from laboratory-reared specimens. The eggs (1.075~1.168 mm in diameter) were weakly adhesive, almost spherical in shape, transparent and unpigmented, showing a pale yellow yolk without oil globules. Hatching was occurred 220 hrs after fertilization at $9.8^{\circ}C$. The newly hatched larvae (3.72~4.40 mm in total length, TL) had 43~47 (11~13+32~34) myomeres, mouth and anus which was not yet opened. The yolk was completely absorbed at 4.58 mm TL, and transformed to postlarval stage. Locations of the anus and second dorsal fin origin, and distinctive growth of the larvae head were observed at 5.48 mm TL with melanophores in the gill cover and upper region of the occipital. In addition, melanophores were distinctive in the ventral region and caudal fin base at 6.88 mm TL. All fins were formed with a complete set of fin rays having the following counts (D. 3~7-12~14-13~14; A. 13-15) at 11.54 mm TL. Both lateral line and barbel of lower jaw were observed at 15.07 mm TL.

• Korean Journal of Ichthyology
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• v.8 no.1
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• pp.83-89
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• 1996

The early life history of Korean bullhead, Pseudobagrus fulvidraco was studied to obtain some information required in aquaculture and reinforcement of natural population. The fertilized eggs were almost spherical in shape and demersal. The egg membranes were transparent with minute folds on the surface, causing them to stick to other substrates. Yolk is yellowish without oil droplets. The eggs just after fertilization were measuring $1.4{\pm}0.03mm$(1.3~1.5mm, n=10) and expanded to $1.7{\pm}0.08mm$(1.6~1.8mm, n=10) in diameter in 1.5 hr. The blastodisc was formed in 30 min and cleavage started in 1 hr after fertilization, and the intervals of each stage of cleavage was about 30 min at $25.0^{\circ}C$. The yolk from 32-cell stage to gastrula stage partly depressed and the depressed part moved clockwise. Hatching occurred in 53 hr after fertilization and hatched embryos had 18~19+20~21(38~40) myomeres measuring 4.2~4.3mm in total length. At the age 7 d after hatching, 4 pairs of barbels were already formed ; 1 pair on the posterior part of the nostril, 1 pair on the upper jaw, and 2 pairs on the lower jaw. And the posterior margin of caudal fin changed into two folds. The lateral band and the form of all fins were completed in 3 weeks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.380-386
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• 1986

Snailfish, Liparis tanakai (Gilbert et Burke) is widely distributed in the coastal waters of Korea and Japan. On December 21, 1985, fertilized eggs of the fish were collected from the coastal waters of Saryang-do island, Kyongsangnam-do, Korea, and the eggs were incubated and the larvae reared at a mean water temperature of $9.2^{\circ}C$ in the laboratory. The fertilized eggs of this species are demersal, adhesive and spherical in shape, measuring $1.68{\sim}1.78mm$ (mean 1.72mm, n=30) in diameter, containing about 20 oil globules. Hatching took place 21 days after blastula stage. During the incubation period water temperature fluctuated between $8.1^{\circ}C\;and\;11.8^{\circ}C$. The newly hatched larvae were $5.70{\sim}6.41mm$ (mean 6.10mm, n=30) in total length with $7{\sim}9$ (abdominal) and 36 (caudal) myomeres. Many melanophores were distributed on the large pectoral fin, yolk sac and peritoneum. Twelve days after hatching, the larvae attained $5.85{\sim}6.46mm$ in total length, and at this time the larvae absorbed the yolk almost completely. Melanophores appeared on the snout and the posterior part of head.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.350-359
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• 2007

The egg development and morphological change of larvae and juveniles of the starry flounder, Platichthys stellatus were observed in laboratory. Fertilized eggs of the species, 1.09~1.19 mm (mean $1.13{\pm}0.03mm$, n=50) in diameter, were floating, colorless, transparent in shape and lacked in oil globules. The eggs hatched out 121 hours after fertilization at water temperature $8.2{\sim}11.2^{\circ}C$. The size of the hatched larvae were 2.58~2.89 mm (mean $2.67{\pm}0.09mm$) in total length, their mouth and anus were not open yet and myotome number was 14+27=41. Melanophore and xanthophore appeared on the notochord and digestive organ and the margin of membrane fin, on the yolk sac and eyes were lacking in pigment cells. 5 days after hatching the larvae attained 4.30~4.97 mm (mean$4.74{\pm}0.21mm$) in TL, and their mouth and anus were open. 10 days after hatching the larvae transformed to postlarval stage and they were 4.67~5.75 mm in TL (mean $5.30{\pm}0.31mm$), and absorbing the yolk completely. Feeding activity increased as the mouth became larger. At 23 days, the larvae attained 6.69~8.82 mm in TL (mean $7.85{\pm}0.75mm$), and the right eye was started moving to the left side of the head. At 52 days, the juveniles attained 10.99~17.06 mm in TL (mean $13.50{\pm}1.67mm$). The right eye was moved completely onto the left side. All of the fins had completed set of the fin rays (D. 64~67: A. 45~51: P. 11: V. 6: C. 19).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.3
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• pp.129-137
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• 1989

Sand fish, Arctoscopus japonicus (Steindachner) is distributed in the coastal waters of East Sea of Korea, Japan, and Alaska. On December 1, 1987, matured adult of sand fish were collected from the shore of Ok-kye, Myongju-gun, Kangwon-do, Korea. The authors carried out artificial insemination on boat. The fertilized eggs were incubated and the larvae were reared in laborato교. The eggs of this species were demersal and adhesive, and their diameter were varied within $3.1\~3.4$mm (mean 3.3 mm, n= 10). They have a number of small oil globules. The spawned eggs in nature were formed the egg mass which were measured ca. 4 m in dia-meter. The hatching took place in 65 days after fertilization at the water temperature of $8.7\~12.3^{\circ}C$. The newly hatched larvae were $8.5\~10.2$ mm in total length with 11 (abdominal) +40 (caudal) = 51 myomeres. 24 days after hatching, the larva attained 19.4 mm in total length, at this time the larvae absorbed the yolk completely, and become postlarvae. 32 days after hatching, the larva attained 23.4 mm in total length, and become juvenile. 56 days after hatching, the juvenile reached 29.9 mm in total length and had adult form. 5 spines of preopercle bone were formed at 24.4 mm in total length. At ca. 15 mm in total length, the form of the pectoral fin was transformed into the adult form.

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.137-145
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• 2000

The embryonic and larval development of Chelon lauvergnii (Eydoux & Souleyet) was surveyed by incubating artificially inseminated eggs with parent fishes obtained at Kang-wha island in the mid-western coastal area of Korea on June, 1997. The fertilized eggs were transparent, spherical in shape, measuring 0.95~1.08 mm in diameter, having a large oil globule, and their perivitelline space narrow, and began to hatch at 40 hrs. in water temperature $22{\pm}1^{\circ}C$. The newly hatched larvae were 2.35~2.68 mm in total length with 23 myomeres, anus opened, mouth closed, preanal length 58.7~61.6% of total length, oil globule located in posterior end of yolk sac. Melanophores, branch in shape, were distributed mainly along the ventro-lateral region of trunk part and a few on the anterior end of caudal part and surface of oil globule. The larvae measuring 3.08~3.36 mm in total length absorbed yolk material completely in 3 days after hatching, in which air bladder began to appear and mouth opened. In 8 days after hatching, the larva was measured 5.09 mm in total length, its posterior end of notochord began to flex upward and the caudal fin rays differentiated as 7, finfold of the second dorsal and anal fins appeared. In this time, melanophores, branch in shape, were concentrated in the anterior half region of the caudal part and a few also distributed on the top of head, snout region, ventral margin of lower jaw and isthmus region. In 12 days after hatching, the larva measuring 8.48 mm in total length completed all the fins (D. IV-9; P1. 16; P2. I, 5; A. II, 9) and reached to the juvenile stage. Melanophores, in this time, were distributed on the mid-lateral region of the caudal part in enlargment than before and a few also found in the dorso-lateral region of the trunk part, and in the cheek region.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.45-56
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• 2009

Current status on the occurrence and the management of the major disease, insect and mite pests were investigated in the organic or non-chemical pest control orchards from 2005 to 2009. Numbers of certified organic or non-chemical apple orchards were increased from 14 in 2005 to 78 in 2008. Severe damages on leaves and fruits occurred by the several diseases such as marssonina blotch, bitter rot, white rot, sooty blotch and flyspeck, and the several insect pests such as apple leaf-curling aphid, woolly apple aphid, oriental fruit moth and peach fruit moth on the almost certified organic or non-chemical pest control orchards. About 10 and 18 environmental-friendly materials were used to control diseases and insect or mite pests respectively. But, lime sulfur and bordeaux mixture to diseases and machine oil, plant oil mixed with egg yolk, and pheromone mating disruptions to insect pests were effective to control under the adequate conditions. At present, it is extremely difficult to produce organic apples in Korea. Growers must consider about and solve so many conditions on the cultivar, weather, local site, marketing and so on, before when they decide to change from conventional or IPM(Integrated Pest Management) to organic or non-chemical pest control orchards.

• Korean Journal of Organic Agriculture
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• v.18 no.2
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• pp.221-232
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• 2010

During 2005~2009, current status on the occurrence and the management of the major disease, insect and mite pests were investigated in the non-chemical or organic cultured apple orchards in Korea. Numbers of certified organic or non-chemical apple orchards increased from 14 in 2005 to 78 in 2008. Severe damages on leaves and fruits were caused by the several diseases such as marssonina blotch, bitter rot, white rot, sooty blotch and flyspeck, and the several insect pests such as apple leaf-curling aphid, woolly apple aphid, oriental fruit moth and peach fruit moth on the almost certified organic or non-chemical pest control orchards. About 10 and 18 environmental-friendly materials were used to control diseases and insect or mite pests, respectively. But, lime sulfur and bordeaux mixture to diseases and machine oil, plant oil mixed with egg yolk, and pheromone mating disruptions to insect pests were effective under the adequate conditions.