• Korean journal of applied entomology
• /
• v.45 no.1 s.142
• /
• pp.91-95
• /
• 2006

This paper reports a simple rearing system for Cnaphalocrocis medinalis based on corn seedlings diet. C. medinalis population under this system has been maintained by four stages (egg, young larva-1st to 3rd instar, old larva-4th to prepupa, 3nd adult) at $25{\pm}2^{\circ}C,\;40{\pm}10%$ RH, 3nd 16L:8D photoperiod in a laboratory. We have elaborated a new egg collection method using a polystyrene container $(top\;{\phi}11.3\;{\times}\;bottom\;{\phi}\;{\times}\;H8cm)$ which has made a great contribution in easy collection of eggs and storage of them for long period. Under this system, pupation and adult emergence rate, and pupal weight of C. medinalis population were close to the other reports by com seedling diet, and superior to those by artificial diets. Therefore, this rearing system would be useful in obtaining C. medinalsis population suitable to each specific needs.

• Korean journal of applied entomology
• /
• v.45 no.3 s.144
• /
• pp.283-291
• /
• 2006

The efficiency to detect mutagenicity of the system using a specific locus mutation of Bombyx mori was examined and improved. In the system, mutagenicity could be detected by the egg colour manifested by the pe and/or re genes, which is a kind of recessive visible mutation of the insect. Among tested four mutagens, MMC had specially high sensitivity in the oocytes of silkworm and EMS had in the spermatozoa. PCB and dioxin showed a positive effect in both the oocytes and spermatozoa. In a consequence of sensitivity of mutagen by mating number of male moth of B. mori, treated mutagen, there was no difference between one mating - and three mating - male moth in sensitivity of mutagen. Sun3ho, B. mori variety, which showed high sensitivity to mutagens was improved in the major characteristics by crossing of C5 and N12.

• Journal of Korean Society of Forest Science
• /
• v.94 no.4 s.161
• /
• pp.277-280
• /
• 2005

In order to prevent chestnuts from damage by the peach pyralid moth, Dichocrosis punctiferalis, a sprinkler system was installed on the chestnut orchard. Such a test was conducted at Yeoju-gun, Gyeonggi-do, Korea in 2002. Insecticides of fenitrothion 50% EC, x1,000 and diflubenzuron 25% Wp, x2,500 were sprayed at ten-day fifteen-day and twenty-day intervals during the period of D. punctiferalis adult occurrence by sprinkler system. The peach pyralid moths generally emerged for about 60 days from early July to early September, and peak emergence was 10 days from late July to early August. Damage rate of chestnuts were 0.9-4.0% on average with this crown insecticide spraying with diflubenzuron, while 30.4% when not treated. Control effectiveness of this insecticide spraying was 92%(86.7-97.0%). In conclusion, effectual times and number of insecticide application with sprinkle system against peach pyralid moth were from early July to late August and four or five times at ten or fifteen day intervals, respectively.

• Korean journal of applied entomology
• /
• v.55 no.4
• /
• pp.439-444
• /
• 2016

Maruca vitrata is a main insect pest against crops of Vigna species (V. angularis and V. radiata) and Sesbania sesban in Fabaceae, but the life cycle of the insect is unclear in Korea. In order to know over-wintering possibility, its stage of the insect, over-wintering entry season, and the first adult emergence season of the next year, we investigated over-wintering rates of the insect in outdoor conditions in Suwon ($37^{\circ}16^{\prime}N$ $126^{\circ}59^{\prime}E$ 35ASL). In all colonies which the rearing for larvae, pupae and eggs started after mid-September, adults did not emerge within the year, and all insects died before next June. In several trials for over-wintering of larvae and pupae in soil, all insects died, too. Larvae stored during specified periods at low temperatures (10 and $13^{\circ}C$) did not emerge. From the results, it was postulated that M. vitrata does not have an adaptability to temperature below zero, and cannot over-winter in Suwon area.

• Korean journal of applied entomology
• /
• v.33 no.3
• /
• pp.141-147
• /
• 1994

Tne present studies were camied out to ~nvestigate the allele frequency variations of alcohol dehydrogenase (ADH) in natural populat~ons of Drosophiio melonogoster and the correlations of iwo ADH alleles between fitness and ethanol. ADH alleles were found to be polymorphic in natural populations of D. rnelanogaster. The frequencies of FF, FS and SS genotypes were 47.66, 42 18, and 10.16%. respectively, therefore the F gene frequency (68.75) was shown to be hlgher than the S gene (31.25 %). The FF genotype was slightly superior to the SS genotype in both fecundiiy and eclaslon. The frequency of AdhF allele in the small alt>fic~apl opulaliow originated from natural populations was increased for 20 generations on normal media at 25$^{\circ}$C In resistance to ethanol, the FF genotype was supenor to the SS genotype, too. It meant that ethanol as environmental factor might be the selective factor on ADH locus in natural populat~ons of D meionogoster.

• Korean journal of applied entomology
• /
• v.23 no.3 s.60
• /
• pp.172-176
• /
• 1984

The insecticides MIPC, BPMC, carbofuran and diazinon were treated to the brown planthopper (BPH) , Nilaparvata lugens STAL, at the dose levels of $LD_{10}\;and\;LD_{50}$(by topical application)/at the rate of 40kg/ha (product base) (by dusting or broadcasting on potted rice). The BPH population in the first generation was significantly decreased in the topical treatments compared to the untreatment. The number of BPH offsprings was relatively greater at the dose level of $LD_{10}\;than\;of\;LD_{50}$. The number of nymphs, however, were greatly varied with the insecticides. The offsprings from the BPH treated with the rate of 40kg/ha showed longer nymphal periods and higher adult emergence, but except diazinon treatment, rather less egg-numbers were observed. The BPH population density was significantly decreased in general up to 38 days after treatment(DAT) in the treated pots. Among the insecticides tested, however, only diazinon induced greater number of insects at the 54 DAT compared to the untreated pots.

• Korean journal of applied entomology
• /
• v.48 no.3
• /
• pp.327-333
• /
• 2009

Biological Characteristic of Obolodiplosis robiniae and insecticidal activity of some insecticides against larvae of O. robiniae were investigated. Egg was in oval shape, and its color was light orange and became red when close to hatch. Length of the major axis and the minor axis of egg was 0.4 mm and 0.1 mm, respectively. Larval color was milky and size was 2.6 mm. Pupa was deep brown and its size was about 3.2 mm. Wing and abdomen of adult was black and reddish, respectively. Size of female adult was about 3.3 mm, and larger than male adult. Number of eggs in the ovary was $192.3{\pm}50.7$. First emergence was from late April to late May, and second from late May to late June. Third emergence was from late June to late July. Newly emerged adult escaped from soil, and second and third emerged adult escaped directly from gall of Robinia pseudoacacia leaf. Egg parasitoid was identified as Platygaster robiniae and parasite rate was 51.6%. Among test insecticides, imidacloprid 10% WP and thiacoprid 10% FL showed very strong insecticidal activity against larvae of O. robiniae at 48h later after treatment.

• Korean journal of applied entomology
• /
• v.41 no.2
• /
• pp.113-121
• /
• 2002

This study investigated the changes in the fitness of brown planthopper, NilapaHata lugens, to several rice varieties with different resistance background, after multi-generational selection on a resistant rice variety. A susceptible strain of brown planthopper (Dongjin-5) had been reared on the Chungchungbyeo with Bph1 resistance gene for three generations (Chungchung-G3) and six generations (Chungchung-G6), then the fitness change was evaluated by measuring their longevity, fecundity, preferences, and survivorships on the varieties with various background of resistance. After being selected three to six generations on Chungchungbyeo, feeding preference, adult longevity, and fecundity increased, where as nymphal period reduced when they were reared on various varieties with Bph1 gene. The egg Periods were not much different among the varieties fed on, except for the Chungchung-G6 on the rice varieties of Milyang63 (bph2 gene) and Gayabyeo (Bph1+bph2 gene). These results suggest that the susecptible Donajin-5 (Biotype-1) can be easily converted to a resistant biotype-2 capable of overcoming the resistant varieties with Bph 1 gene.

• Korean journal of applied entomology
• /
• v.45 no.2 s.143
• /
• pp.195-200
• /
• 2006

This study was carried out to clarify the biologies and morphological characteristics of Rhynchaenus sanguinipes. Also some chemicals were tested to screen the effective insecticide for the control of the species. Up to date, Zelkova serrata has been hewn as host plant of Rhynchaenus sanguinipes, which shows serious damage in this country. In the present study, Ulmus pumila was first found as host plant in this study. Body lengths of larvae, pupa and adult were 4.53$\pm$0.30 mm, 3.30$\pm$0.42 mm and 2.96$\pm$0.12 mm, respectively. The overwintered adult of the species emerged on early April to late April, and adult of nekt generation emerged on early May to late May, Pupal periods were 10, 7.2, 5.1 and 4 days on 16, 20, 24 and 28$^{\circ}C$, respectively. The lower developmental threshold temperature was 5.8$^{\circ}C$. Four braconid parasitoids were found as natural enemies, which emerged mainly on late April to early June. Insecticidal activities with treatments of fenitrothion 50% EC, indoxacarb 30% WG, ethofenprox 20% EC and thiacloprid 10% SC was investigated against adult of R. sanguinpes, and they showed >90% mortality.

• Korean journal of applied entomology
• /
• v.38 no.1
• /
• pp.23-28
• /
• 1999

This study was conducted to determine the effect of temperatures, 24"C, 28$^{\circ}$C and 32"C,and food sources on pupal development, adult longevity and oviposition of tobacco cutworm, Spodopteralitura Fabricius. Percent pupation of S. litura was became higher at higher temperature from 23% to 88%.And its percent pupation was highest on soybean leaf (SL), followed by perilla leaf (PL), sweet potato leaf(SPL) and artificial diet (AD). Pupal weight ranged from 0.28g on SPL to 0.40 g on PL and was tended toheavier with decreasing temperature. The mean pupal duration was 14, 10 and 7 days at 24"C, 28$^{\circ}$C and32"C, respectively. Percent emergence was in range of 21% to 89% with higher percent emergence as thetemperature increased and both 28$^{\circ}$C and 24$^{\circ}$C was highest on SL, followed by PL, SPL and AD, but at24$^{\circ}$C the order was SPL, PL, SL and then AD. Preoviposition duration was 3.2 days at 24"C, 2.8 days at28$^{\circ}$C and 2.5 days at 32$^{\circ}$C. Adult longevity became shorter as the temperature increased from 6.4 to 3.9days. Male longevity was longer than that of female. Adults lived longest when they were reared on PL,followed by SL, SPL and AD. Total number of eggs laid per female varied from 803 to 1,441 regardlessof the treatments, but those were significantly more on natural foods than on AD. Number of eggs per eggmass was 97.4 at 24$^{\circ}$C 155.8 at 28$^{\circ}$C and 104.7 at 32$^{\circ}$C. Number of egg mass was 12.0, 6.7 and 11.3 at24"C, 28$^{\circ}$C and 32"C, respectively.4"C, 28$^{\circ}$C and 32"C, respectively.