• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.623-629
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• 2011

The detectable levels and population fluctuations of phytoplasmas infecting dwarf mulberry trees were investigated using nested-PCR and competitive-PCR methods. Samples of five different types were studied : A. petiole of a leaf that displays dwarf symptoms, B. petiole from apparently healthy leaf residing on a branch also supports a leaf with dwarf symptoms, C. the branch portion that supports a leaf with dwarf symptoms, D. the leaf petiole from healthy appearing leaves on branch with no dwarf symptoms, and branch portion of branch with no dwarf symptoms, E. the rootlets of trees with dwarf symptoms. These 5-parts were collected from each tree during June - April, once in every two months. The phytoplasma was detected from all parts of collected mulberry samples during all seasons using nested-PCR with AS-1/AS-2 primer pairs. The phytoplasma was detected until $10^4$ dilution using direct-PCR method, but it was detected until $10^{13}$ dilution by the nested-PCR method. The density of pytoplasma was found to be $7.94{\times}10^{18}-10^{12}copies/{\mu}L$ in mulberry trees. The density of phytoplasma was observed throughout the year in all samples of mulberry trees. The highest rates of phytoplasma was found in the samples B and C during the early growing season followed by the sample A and D during the dormant season. Samples C and E displayed the highest phytoplasma density followed sample D. The density of phytoplasma appeared stable during all the seasons for samples C and A. The result of the present study demonstrates the utility of nested-PCR and competitive-PCR for detection and determination of population fluctuations of phytoplasmas in plant tissues.

• Journal of Sericultural and Entomological Science
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• v.32 no.2
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• pp.79-84
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• 1990

To make clear the changes of the amount of reserve substances in the bark of stem and root of mulberry graftages after planting, studies were carried with mulberry graftages classified into three groups of 7.0-7.9mm, 9.0-9.9mm and 11.0-11.9mm in diameter of stems at 3cm above their base. The results obtained were as follow : 1. The dry weight of stem and root bark gradually decreased with growth of new shoots till about five weeks after planting, and from then it increased. 2. The duration of new shoots growth depending on the reserve substance was limited for 6-7 weeks after planting. In no fertilized group, the length of new shoots increased up to 6-7 weeks, form then decrease. 3. Dry leaf yield three weeks after planting was found to be no difference in the same diameter of saplings between with and without fertilization. 4. The content of chlorophyll in the leaves was higher in thicker group and in fertilized group than thinner and no fertilized one, respectively. 5. There was no difference in the amount of carbohydrates of the bark of stem and root among the stem diameters. There was a transient increase in the amount of total sugar in the bark of stem and root in the first three weeks after planting, followed by gradual decline up to five weeks. The amount of reducing sugar in the bark of stem and root increased both in fertilized and in no fertilized group up to three weeks after planting, and then it decreased. There was a gradual decline in the content of starch in the bark of stem and root both in fertilized and in no fertilized group up to five weeks after planting, followed by gradual increase.

• Journal of Sericultural and Entomological Science
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• v.36 no.2
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• pp.102-109
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• 1994

Profitability was analysed in the fields of various planting densities from 1,666 trees/10a to 4,166 with mulberry grafts or conventional saplings under the consideration of leaf yield and quality. Leaf yield per tree decreased with the higher planting densities. Seasonal and total leaf yield per area, however, increased by 20 to 63% as a mean for 3 years in the densities of 2,083~4,166 trees per 10a than in the conventional density of 1,666 trees per 10a. The increase in leaf yield per area was not so high in the densities over 2,083. Leaf yield in the sapling plots was a little higher than that in the graft plots. Topping of shoot tip affected neither on the branch length nor on yield. Yield was higher in the planting spacing with single raws than in that with double raws. Quality of leaves in the densities from 2,083 to 3,333 trees per 10a was relatively good judged based on the results of the pupation rate and cocoon yield and quality.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.985-994
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• 2019

Muberry (Morus alba L.) leaves fermented with Hericium erinaceum mycelium (MA-HE) were assessed for the protection against oxidative modification of antioxidant enzymes, Cu,Zn-superoxide dismutase(SOD) and ceruloplasmin(CP). MA-HE were shown to significantly inhibited oxidative modifications and inactivations of Cu,Zn-SOD and CP induced by peroxyl radical. Antioxidant activity of MA-HE evaluated using peroxyl radical scavenging assays. MA-HE showed 44.03% of peroxyl radical scavenging activity at $100{\mu}g/mL$. Thus, MA-HE protect the antioxidant enzymes from oxidative damage by the scavenging peroxyl radicals. The results suggested that MA-HE was effectively removed reactive oxygen species in cells, thereby protecting cytotoxicity caused by oxidative stress.

• Journal of Sericultural and Entomological Science
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• v.7
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• pp.1-26
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• 1967

In order to develop the standards for the measurement of drought resistance in mulberry trees (Morus genus) the varietal differences of drought resistance were measured for 30 mulberry varieties, and the relationships between the drought resistance and the histological and physiological characteristics of mulberry leaves were investigated. The results were summarized as follows; 1. It is reasonable to use the drought resistance ratio, expressed by D/D'＊100, for the standard of drought resistance measurement for mulberry tree as a perennial tree crop. Where: D stands for growth amount(shoot length) in the plot of dry treatment, at the end of treatment. D' stands for an expected value of D which is expressed by B＊C/A. Here, A is the growth amount of wet treatment plot at the beginning of treatment, B is the growth amount of dry treatment plot at the beginning of treatment, and C is the growth amount of wet treatment plot at the end of treatment. 2. The results obtained from the application of above formula showed that the varieties Cadaneo, Tahozosaeng, Yongchunchuwu, Kaeryang suban. and Kabsun were highly resistant to drought and the varieties Jukmok, Shipyung, Sobun, Kaeryangzosaeng shipmoonza and Chungagokyo were highly susceptible. 3. Among leaf tissues. the rate of inter-cellular space showed the highest relationship with drought resistance. The correlation coefficient calculated (r=0.4153) was highly significant. Other leaf tissues such as epidermis and palisade showed no significant correlations with drought resistance. 4. The size and density of stomata were correlated to drought resistance. That is: Correlation between drought resistance and size of stomata(length ${\times}$ width)......r= -0. 3253(signif. at 5%) density(No. of stomata/l$\textrm{mm}^2$......r= +0.5047(signif. at 1%)

• Journal of Sericultural and Entomological Science
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• v.6
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• pp.1-8
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• 1966

Various relationships with the leaf yield per 1,000m in the length of mulberry branch were investigated. The results obtained are as followings. 1. Relationship with the mulberry varieties. There were little differences of the leaf yield among the mulberry varieties, being 106∼109kg in an average and the distributions of the leaf yield were of 60∼160kg class for Morus bombycis Koidz, 50-17kg class for Morus Lhou(Ser.) Koidz and 50∼180kg class for Morus alba L. Otherwise, 79 per cent of all varieties was between 80∼140kg class to which 85 per cent of only Morus Lhou(Ser.) Koidz belonged. There was one or two peaks for each strains, for example, the peak at 80∼90kg class and at 120∼140kg class in Morus bombycis Koidz showed the best yield, the peak at 90∼100kg class in Morus alba L. and 100∼110kg class in Morus Lhou(Ser.) Koidz. 2. Relationship with the pruning. The multi-stemed pruning showed 149kg mulberry leaf yield which was more 75 per cent increase than the low-stemed pruning, 85kg. 3. Relationship with the degree of cutting off. The leaf yield varied according to the degree of cutting off the branch, such as, 166kg in 1/3 cutting off the branch and 180kg in $\frac{1}{2}$ which were more 19 per cent and 34 per cent increase of 140kg in non-cutting off the branch, respectively. The main cause of the leaf increase was thought because of the increase of young branch. 4. Relationship with the branch diameter. In the relation to the leaf yield per 1,000m in branch length, there was no significance comparing 66kg for thin branch with 80kg for medium one ana the thick branch had 150kg leaf yield and increased 88 per cent when compared with the medium one. In the relation to the leaf yield per l0cm in diameter, 811g leaves for thin branch and 875g for medium one were produced, but there was no significance between them. Thick branch had 1,461g, and increased 67 per cent when compared with medium one and the average yield was 1,201g for total branch.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.155-159
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• 2000

In the spring silkworm rearing period of year 1998, some nutritional aspects were studied in the Agricultural Research Station of the Komotini town in Greece, to investigate the feeding behaviour of some Bulgarian silkworm hybrids, suitable for spring rearing, during the fourth and fifth instal under the local climatic conditions. The silkworms were fed by locally cultivated Japanese Kinriu mulberry (Morus alba L.) variety leaves. Eight Bulgarian hybrids had been used, namely Vratza-53xVratza-52, Ukraine-20xVratza-53, Super 1xHessa 2, Merefa 2xVratza 35, as well as their reciprocal crosses. The studies showed out a remarkably higher feed intake and feed utilization by the hybrids Hessa 2xSuper-1, Merefa 2xVratza 35 and Vratza-52xVratza-53. The same hybrids showed an efficient food utilization by means of daily growths cocoon shell ratio and raw silk output. In terms of food to silk conversion efficiency Hessa 2xSuper-1 hybrid gave the best results. Larval stage duration for fourth and fifth instar was not affected by feed intake and utilization. All hybrids showed a good adaptation to the local environment and their feeding performance was equal to the international existing standards. All calculated parameters were found to be around the mean values of other up to date presented results and thus considered as acceptable for the needs of the local production.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.171-174
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• 2002

Two systemic fungicides, SF1 (Bavistin, a carbandazim fungicide 50% WP, Rallis India ltd., India) and SF2 (Bayleton 25% WP-Triadiamefon, a Triazole compound, Rallis India Ltd., India) were screened for control of muscardine disease in silkworm, Bombyx mori. One and two percent of SF1 and 0.05 and 0.1 % of SF2 in aqueous solution were found to be effective in in vivo condition for the control of the disease. These fungicides, on feeding through mulberry leaves continuously for two days to 4$^{th}$ and 5$^{th}$ instar silkworm larvae inoculated topically with conidia of Beauveria bassiana (4$\times$10$^{6}$ conidia/ml) resulted in reduction in mortality due to muscardine by over 90% as against 100% mortality in inoculated control. SF1 at 1% reduced the mortality by 90% in 4$^{th}$ instar and 91% in final instar silkworm while at 2%, the reduction was 92% and 96%, respectively. SF2 at 0.05 and 0.1 % concentration reduced the mortality by 82 and 88% during 4$^{th}$ instar and by 88 and 92% during 5$^{th}$ instar, respectively.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.127-131
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• 1995

A crude crystal of phytoecdysone was obtained 355 mg per Kg dry radix of A. japonica, and it was identified to $\beta$-ecdysone by TLC. Feeding silkworms on mulberry leaves sprayed with the extract, mounting time shortened and pupation ratio improved. The feeding effects of the extract was differed according to the rearing seasons, spring and summer. In spring season, only mounting time shortened without any difference in pupation ratio from the control. In summer season, not only mounting time shortened, but also pupation ratio remarkably advanced.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.146-153
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• 1997

The microsporidian infection with Nosema bombycis, reconfirmed its high virulence and transovarial tranmissibility, however, the characteristic symptom of the spots like pepper grains on the diseased larval skin was no more recognized by present varieties of the silkworm. Transovarial transmission rate detected from moth was above 90% in dead eggs or dead larvae in the rearing by mulberry leaves, 80% in the newly hatched larvae starved to death. Transovarially transmitted N. bombycis was easily observed from dead eggs and larvae, and were suggested an individual inspection of a few of dead eggs for detection of the pathogenic spores. The progeny population provided indicative factors on the sampling of predictive and corrective inspection. The higher concentration of N. bombycis spores included in the hindabdormal part of infected moth, applicative on the simple method of indivisual moth inspection. For the predictive inspection of growned 5th-instar larvae, N. bombycis infection was detectable without microscopic observation by the unique symptom of turbid milky-white spots on the silk gland. Inspection of the meconia artificially discharged from silkworm moth, was also succesful of microscopic observation before crossing, without killing or homogenize the moths. The results provided a basis of rational methods for the inspection of N. bombycis infection of the silkworm.