• Korean journal of applied entomology
• /
• v.19 no.4 s.45
• /
• pp.243-248
• /
• 1980

Experiments were conducted to study on bionomics and control of cutworms; Agrotis tokionis, A. ipsilon, A. fucosa in Suweon, 1978-1979. A. ipsilon and A. fucosa had two or three generations and A. tokionis had one generation a year. A large number of A. toikonis occured at the end of September, and the major peaks of the first generation of A. tokionis and A. fucosa were in mid-June, the second generation in mid-August, and the third generation was at the end of September. These cutworms laid many eggs on the lower surface of curved downward leaf of Chinese cabbage and the larvae later than 3rd instar began to cut the basal part of stem and then pulled into the soil. A parasite of A. tokionis, a braconid wasp, Meteorus rubens, and two unidentified Ichneumnid wasps were found. Mocap and Volaton gave effective control to the cutworms but Volaton should be applied not to contact with plant.

• Korean journal of applied entomology
• /
• v.50 no.4
• /
• pp.283-288
• /
• 2011

Occurrence of Scrobipalpa salinella (Zeller) was investigated on glasswort in Shinan, Jeonnam and Kimjae, Jeonbuk from 2010 to 2011. The occurrence of S. salinella observed four times in a year. Adult stages of S. salinella in two areas occurred from mid-April to late September. The peak times of 1st, 2nd and 3rd generation adults of S. salinella was observed on early May, mid-June, late July (in Kimjae) to early August (in Shinan) and early September, respectively. And larval stages of S. salinella occurred from late May to late August. The peak times of development of 1st, 2nd and 3rd generation larvae of S. salinella was observed on mid-June, mid-July and mid-August, respectively. However, the 4th generation larvae began to occur in mid-September but didn't damage in glasswort. Among the distances from the bank of glasswort field (3, 6, 9 m) and periods of damage (Jun. 16, Jul. 7, Aug. 12), larval density in 3 m distance from the bank in 1st damage season (Jun. 16) was high which resulted to severe damage. Damage of 2nd and 3rd generation larvae was progressed both density of larvae and levels of damage.

• Korean journal of applied entomology
• /
• v.54 no.2
• /
• pp.73-81
• /
• 2015

A Cohort based model for temperature-dependent population dynacmics of Riptortus pedestris was constructed by using a commercial software (DYMEX) and seasonal occurrence along with pesticide treatments effect was simulated and validated with pheromone trap data. Ten modules of DYMEX software were used to construct the model and Lifecycle module was consisted of seven developmental stages (egg, 1 - 5 nymphal instars, and adult) of R. pedestirs. Simulated peaks of adult populations occurred three or four times after the peak of overwintered populations which was similar to those observed from pheromone trap catch. Estimated dates for the second peak were quite similar (1-2 day difference) with those observed with pheromone trap. However, the estimated dates for the first population peak were 9-16 days later than the observed dates by pheromone trap and the estimated dates for the last peak were 17-23 days earlier than the observed dates. When insecticide treatments were included in the simulation, the biggest decrease in R. pedestris adult density occurred when insecticide was applied on July 1 for the first peak population: the estimated adult density of the second peak was 3% of untreated population density. When insecticide was assumed to be applied on August 30 for the second peak population, the estimated adult density of the following generation was about 25% of untreated population and the peak density of the following generation reached about two weeks later than untreated population. These results can be used for the efficient management strategies for the populations of R. pedestris.

• Korean journal of applied entomology
• /
• v.34 no.2
• /
• pp.147-153
• /
• 1995

The occurrence of Oriental Tobacco Budworm (OTB), Helicoverpa assulta (Guenee), larvae in early and late planted tobacco fields showed tow or three distinct peaks. The parasitoid, Campoletis chlorideae Uchida, occurred for a short period with one peak following th second peak of OTB in early planted fields. However, in late planted fields, the parasitoid occurred as long as the OTB larvae were abundant. The OTB larval density was higher in late planted fields than in early planted fields. Among four varieties of tobacco, the OBT larval occurrence was relatively high on NC-744 throughout the season. However, more parasitoid cocoons were found in Burleyf-21 and NC-82. The seasonal occurrence of the larval parasitoid, C. chlorideae, assessed by an OTB larval release and recovery method, continued from late June to early September and relatively higher abundance was noticed from early July to late August. In a field cage evaluation of C. chlorideae as a biological control agent of OTB larvae, higher rate of C. chlorideae release (4 females/2$\m^2$) resulted in higher larval parasitism (86.1%) and less leaf damage (8.7%) in tobacco. The leaf damage by OTB larvae was significantly high in the untreatment plot (23.2%) and the lowest damage (1.6%) was recorded in the chemical treatment plot.

• Korean journal of applied entomology
• /
• v.53 no.1
• /
• pp.1-6
• /
• 2014

The pink citrus rust mite, Aculops pelekassi (Keifer) (Acari: Eriophyoidea), is an important pest in the citrus orchards of Jeju, Korea. This study was performed to investigate the seasonal population abundance of A. pelekassi, and the effects of humidity and citrus leaf age on the multiplication of this pest. Relative humidity (RH) significantly affected the longevity and fecundity of A. pelekassi. Longevity was 7.5, 14.5 and 14.6 d and fecundity was 5.4, 21.5, and 27.1 eggs at 33, 75 and 84% RH, respectively. The leaf age of citrus significantly affected the multiplication of A. pelekassi. The population abundance on 40 day-old leaves was much higher more than 3 times that on 10-day old leaves at 4 weeks after introduction. Overwintered A. pelekassi adults between the bud scales of the citrus trees became active in late April; they were found on newly emerged leaves, followed by their settlement on young fruits in mid-June. The population levels of A. pelekassi peaked on the leaves in late June to July, and on the fruits in early August. The results obtained in this study should be useful for the control of A. pelekassi in citrus orchards in Jeju.

• Korean journal of applied entomology
• /
• v.48 no.3
• /
• pp.295-299
• /
• 2009

Adoxophyes spp. (Lepidoptera: Tortricidae) are economically important pests of fruit trees in Asia and Europe. The geographical distribution of three Adoxophyes species, A. orana, A. honmai and A. paraorana, in Korea was surveyed using species-specific sex pheromone traps for males in 2006 and 2007. The distribution of A. orana was restricted in the midwestern area, while A. honmai was found mainly in the southern area. In contrast to these two species, A. paraorana was widely distributed. Moreover, A. paraorana coexisted with A. orana in the midwestern area, and with A. honmai in the southern area. The seasonal fluctuation of male catches was monitored with pheromone traps in 2008. In the central regions, males of A. orana and A. paraorana were captured from May to September, with peak numbers in late May, middle July, and late August. A. honmai males were trapped from late April to late September, with peak catches in middle May, late June, early August, and early September in Naju.

• Korean journal of applied entomology
• /
• v.43 no.2
• /
• pp.103-109
• /
• 2004

Seasonal occurrence of Japanese gall-forming thrips, Ponticulothrips diospyrosi Haga et Okajima, and its damage pattern on leaves and fruits were studied at sweet persimmon orchards in Gimhae (orchard A, B) and Changwon, Gyeongnam. Korea in 2002 and 2003. Monitoring adults by yellow sticky traps and inspecting each developmental stage in damaged rolled-leaves revealed that the overwintered adults moved to sweet persimmon orchard from late April to late May, and oviposited inside the rolled leaves. Adults developed from the eggs showed peak occurrence of the first generation adults in early to mid June. Inspection of rolled leaves indicated that the peak occurrences of eggs, nymphs, and pupae of the first generation took place in early to mid May, late May to early June, and early June, respectively. Each developmental stage showed the second small peaks in the late season. Results suggest that most thrips live a single generation per year, but a small portion may develop to the second generation in persimmon orchards. The percent of damaged leaves was highest in Changwon orchard at 9.7％ in early June. Percentage of damaged fruits increased from 0.84％ in early June to 30.2％ in early September in Gimhae B orchard. It was found that the closer the persimmon trees were to the edge of the orchard, the worse damaged the leaves were. Appropriate timing for incorporation of control measures were discussed in relation to the seasonal occurrence of adults.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.33 no.1
• /
• pp.74-80
• /
• 1988

Seasonal population changes in Laodelphax striatellus Fallen (small brown planthopper), percentage of rice black-streaked dwarf virus (RBSDV) viruliferous L. striatellus, and RBSDV infection of 11 corn hybrids were observed at various locations and years. The population size of L. striatellus was relatively small in the middle parts of Korea, but it was much greater in the southern areas. The population size of the first generation of adult L. striatellus emerged from late April to early May was similar or smaller compared with that of the second generation emerged in middle June in the middle parts of Korea. However, in the southern areas the population size of second generation was much greater than the first generation. The percentage of RBSDV viruliferous L. striatellus differed depending on the years, locations, and testing methods. The percentage of viruliferous vector was highest in southern plain areas and it tended to decrease with distance from the areas. The percentage of viruliferous vectors tested by enzyme-linked immunosorbent assay was higher than that tested by rice seedling test. The RBSDV infection rate of corn hybrids was highest at Daegu and ranged from 9 to 39% probably due to both a higher L. striatellus population and a higher percentage of viruliferous vectors. However, it was significantly lower in other areas and ranged from 0 to 13%.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.4 no.1
• /
• pp.109-114
• /
• 1968

In order to investigate the growth pattern of sugar beet in Korea, this experiment was conducted using variety GW 359 at Tae-kwan-ryong, Suwon and Cheju. The results are summarized as follows; 1. At Tae-kwan-ryong, early growth stage was relatively long and during higher growing stage plants showed resistance to leaf spot disease, and vegetative maturing started from about September 15th. Top and root growth showed normal curve but it is considered that the early maturing variety will reduce the early growing period and prolong the vegetative maturing period. 2. At Suwon, the growth of top part was favorable until late of July but hereafter leaf spot disease brought death to the 25-35 leaves of top part and regenerated again in October. Consequently, sugar content of root showed changes from decrease to increase. Root weight increased from July to harvest season continunousely but showed abnormal growing curve. This indicates that Suwon is not proper place for sugar beet cultivation. 3. At Cheju, early growing stage was shorter about 15 days than that of Tae-kwan-ryong. Normal growth and long-maturing days favored the sugar accumulation in roots. But it is necessary to introduce non-bolting variety in autumn-winter season culture. 4. Sugar beet could be cultivated economically at Tae-kwan-ryong with 600-800 meter altitude for summer crop and at Cheju for winter crop, but Suwon is considered to be unfavorable for sugar beet.

• Korean journal of applied entomology
• /
• v.29 no.4
• /
• pp.230-237
• /
• 1990

Studies were carried out to examine seasonal occurrence and emergence pattern of the onion fly, Delia antiqua (Meigen), in the field of Chinju city in Gyeongnam province from 1984 to 1987. Trap catch revealed that the onion fly had three generations in a year, the second flight being partial; the peaks of adult occurrence were at mid April for the overwintered generation (1st flight), at early June for the first generation (2nd flight), and at the period from late September to early October for the autumn generation (3rd flight). It was shown that parts of the pupae in the first and almost all of the pupae in the second (or autumn) generation underwent summer diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapaused pupae were form 8.5 to 145 days in the first generation in he filed, being shorter for the pupae pupated later. This resutled in synchronization on the emergence of these diapaused pupae at late September, with the adults from the second generation pupae. The ratio of diapausing pupae increased among the later pupated ones in the first generation ; the pupae which had been pupated in early May included 43.8% of diapausing pupae, while more than 86.7% of the pupae were under diapausing state for the pupae pupated in late May and thereafter. More than 93.3% of the pupae went into diapause, regardless of pupation time for the second generation.