Showing papers in "Jarq-japan Agricultural Research Quarterly in 1997"

Prospect for Integrated Pest Management in Tea Cultivation in Japan

Abstract: Tea plant is perennial and evergreen, and leaves are stratified into 2 layers. The bush below the plucking surface is very important as a refuge for natural enemies because of minimal artificial effects. The ecosystem of tea field is the most complex and most stable among the Japanese agroecosystems. Most of the tea pests are polyphagous and complete their life cycle in tea fields Since the effects of natural enemies on the population of insect pests are pronounced even under insecticidal control because of the complexity of the ecosystems, excessive insecticide application is not recommended and conservation and utilization of indigenous natural enemies should be promoted in the control system of tea pests. A tentative IPM system for tea cultivation in Japan was proposed. In the system, both natural enemies and insecticides are used complementarily. Discipline: Insect pest/Tea industy Additional key words: agroecosystem, economic injury level, insecticide resistance, natural enemy JARQ 31, 213-217 (1997)

Utilization of Oil Palm Frond as Cattle Feed

Abstract: A series of studies was conducted on the processing and utilization of oil palm frond (OPF) as a cattle feed. Chemical analysis revealed that OPF was composed of 70% fiber and 22% soluble carbohydrates on a dry matter basis. It was shown that OPF could be conserved as silage by determining the pH value and organic acid content in the silage. Urea addition at 1 to 2% (on a dry matter basis) at ensiling was found to be effective to prevent aerobic deterioration of OPF silage after opening of the silo by monitoring the change of temperature in the silage after exposure to the air. Nutritive value of OPF silage was found to be as high as that of rice straw based on voluntary intake and digestibility determined by the digestion trials using Kedah-Kelantan bulls. Feed intake, growth and carcass characteristics in Australian Commercial Cross fattening bulls, and feed intake and milk production in Sahiwal-Friesian lactating dairy cows were determined in the respective feeding trials and it was found that the optimal inclusion level of OPF in the diet ranged from 30 to 40% and was 30% for beef cattle and dairy cows, respectively. OPF has been found to be a suitable substitute for tropical grasses and has been successfully adopted by the ruminant producers in Malaysia. Discipline: Animal industry Additional key words: tropics, silage, digestibility, beef, milk

Inheritance and Selection Efficiency of Bacterial Wilt Resistance in Tomato

Abstract: Bacterial wilt resistance of F2, F3, F4 and F5 generations was evaluated in tomato. Parents and each generation were transplanted into a field heavily infested with Pseudomonas solanacearum and inoculated with bacterial wilt. Bacterial wilt resistance was evaluated based on the date of plant death and a resistance index from 1 (susceptibility) to 13 (high resistance) was assigned to each plant. Mean resistance indices of the F1 generations of the 2 crosses were 4.5 and 6.2, which were lower than the mid-parent values of 6.9 and 7.1, respectively. These findings suggest that bacterial wilt resistance is partially recessive as there was incomplete dominance toward susceptibility. There was no correlation between the resistance index and fruit weight in the F2 generations of the 2 crosses (r = -0.074, r = -0.019), indicating that it is possible to select plants with both high resistance and large fruits in segregating populations. High parent-offspring correlation between the resistance indices of the parental F2 plants and the resistance indices of the F3 progenies was observed and the mean resistance indices of F3, F4 and F5 progenies derived from highly resistant F2, F3 and F4 plants were higher than the mean resistance indices of the progenies derived from susceptible or moderately resistant F2, F3 and F4 plants. These findings indicate that selection of resistance in early generations is apparently effective. Discipline: Plant breeding/Horticulture Additional key words: breeding, Lycopersicon esculentum, fruit weight, correlation, Pseudomonas solanacearum JARQ 31, 195-204 (1997)

Eradication of the Melon Fly, Bactrocera cucurbitae Coquillett, by Mass Release of Sterile Flies in Okinawa Prefecture, Japan

Abstract: In 1972, MAFF, Japan and the Okinawa Prefectural Government initiated an experimental eradication project of the melon fly from Kume Island, Okinawa Prefecture, Japan using the sterile insect technique (SIT). Following the successful eradication on Kume Island in 1978, large scale SIT was started to eradicate the melon fly on the 3 groups of islands, Miyako, Okinawa and Yaeyama of Okinawa Prefecture, Japan in 1984, 1986 and 1989, and eradication was achieved in 1987, 1990 and 1993, respectively. For the successful eradication on Miyako, Okinawa and Yaeyama groups of islands, about 6,340, 30,940 and 15,440 million sterile melon files were released, respectively. Discipline: insect pest Additional key words: male annihilation, SIT (sterile insect technique)

Application of Near Infrared Reflectance Spectroscopy to Forage Analysis and Prediction of TDN Contents

Abstract: Near infrared reflectance spectroscopy (NIRS) method was used to predict the chemical composition and total digestible nutrients (TDN) content of forage. A total of 388 out of 503 samples were used to develop the calibration equation. The samples consisted of temperate grass in the form of hay (n = 126), silage (n = 120), and its hay-silage mixture (n = 60), and corn silage (n = 142). The remaining 115 forages samples including temperate grass hay (n = 58), silage (n = 39), and corn silage (n = 18) were used to validate the developed calibration equations. These samples were analyzed in duplicate for moisture, crude protein (CP) and crude fiber (CF) contents by the proximate method. Organic cellular contents (OCC), organic cell wall (OCW), low digestible fiber fraction (organic b fraction: Ob), and high digestible fiber fraction (organic a fraction: Ob) were determined by an enzymatic method, while acid detergent fiber (ADF) was determined by a detergent method. Accuracy of the predictions was assessed by the correlation coefficients (r) and standard error of prediction (SEP). Two prediction methods of the TDN by NIRS were compared. In the first method, NIRS values were extrapolated to the TDN value calculated by the following equations (indirect method): (1) equation in Adams method, (2) equation in Martin method, (3) Donker equations, (4) equations based on enzymatic analysis, and (5) equation for detergent method. In the other method, the in vivo TDN was directly calibrated (direct method). In vivo value was obtained from digestion trials carried out in sheep. In the prediction by NIRS method, the r and SEP values of hay were 0.98 and 0.96 for CP, 0.79 and 2.95 for CF, 0.92 and 2.44 for OCC, 0.91 and 3.01 for OCW, 0.81 and 4.80 for Ob, 0.74 and 2.44 for ADF, respectively. Similar values were obtained for grass silage. However, lower r and higher SEP values were observed in corn silage compared with the hay samples used in this study. These results indicated that the moisture, CP, CF, OCC, OCW, Ob and ADF contents in forage samples can be predicted by using NIRS techniques with an acceptable accuracy. For the TDN, in the case of the indirect method, an r value of over 0.7 and a standard error (Se) of 1.5-3.8 were obtained from calibration based on the equations of Adams, Martin, and enzymatic analysis in hay. However, for corn silage a very low r value, below 0.5, and Se values of 0.8-3.8 were obtained. In the direct method of TDN calibration, correlation coefficients over 0.8 and standard error of 2.3-3.4 for all the feed groups were recorded. Discipline: Animal industry Additional key words: corn silage, grass silage, hey JARQ 31, 55 63 (1997)

Successive Transmission of Resistance to Bluegrass Webworm to Perennial Ryegrass and Tall Fescue Plants by Artificial Inoculation with Acremonium Endophytes

Abstract: Perennial ryegrass (Lolium perenne) and tall fescue (Festuca arundinacea) plants were imparted the resistance to the bluegrass webworm (Parapediasia teterrella Zincken) by artificial infection with Acremonium sp. and A. coenophialum, respectively. The Acemonium endophytes were isolated from perennial ryegrass and tall fescue plants which were resistant to the larvae of the bluegrass webworm. The endophytes were inoculated by inserting the mycelia from the pure culture into the meristematic region. The presence of hyphae of the Acremonium endophytes in the inoculated plants was monitored by light microscopy 1-2 months after inoculation. The percentages of successful infection of perennial ryegrass with Acremonium sp. were 9-33%, and that of tall fescue with A. coenophialum was 7%. There were no differences in the appearance between the endophyte-infected plants and uninfected ones. The plants infected with the endophytes had acquired a feeding deterrent to the bluegrass webworm and the survival rate of the larvae on the infected leaf blades was definitely lower than that of the larvae on the uninfected leaf blades. The endophytes were transmitted to all seeds which were produced by the artificially infected perennial ryegrass and tall fescue plants. The plants grown from the seeds had also acquired the feeding deterrent to bluegrass webworm. Discipline: Biological control Additional key words: feeding deterrent JARQ 31, 109 115 (1997)

Photo-Deterioration of Chemically Modified Wood Surfaces : Acetylated wood and alkylated wood

Abstract: Acetylation with acetic anhydride and alkylation with butylene oxide were applied to sugi (Cryptomeria japonica D. Don) veneers and blocks and the treated surfaces were evaluated for their photo-resistance using XPS (X-ray photo-electron spectroscopy) and colorimetry. Chemical modification treatments were expected to increase the weathering resistance of wood and the durability of weathering-resistant transparent type of coating films. Color changes on the chemically modified wood surfaces upon exposure to UV light were less conspicuous than those of untreated wood surfaces, but the photo-oxidation of modified wood surfaces, as estimated using XPS, was similar to that of untreated wood. Chemical modification did not increase the bonding strength or weathering resistance of transparent coating films. Discipline: Forestry and forest products Additional key words: weathering resistance, XPS, colorimetry, ultraviolet ray, transparent finishing JARQ 31, 147-154 (1997)

New Application of Konjac Glucomannan as a Texture Modifier

Abstract: In addition to being used as a material for the preparation of traditional alkaline gel, konjac glucomannan (KGM) can be utilized as a texture modifier under neutral or acidic conditions. Rheological and thermal properties of KGM with different molecular weights were studied under neutral conditions to promote further utilization. KGM molecules showed a coil overlap and entanglements even at a low concentration (0.01%). The mixed gels of-KGM and x-carrageenan (CAR) were considered to involve 2 crystalline regions: one consisting only of CAR molecules and the other consisting of the interaction between CAR and KGM. Upon heating, the latter region was disintegrated at a lower temperature and the former melted at a higher temperature. Gels containing KGM with a higher molecular weight or a higher KGM content have a stronger tendency to make junction zones formed by CAR and KGM. Discipline: Food Additional key words: differential scanning calorimetry, gel, viscoelasticity. Viscosity JARQ 31, 301 -'306 (1997)

Epidemiological Aspects of Citrus Huanglongbing (Greening) Disease in Thailand

Abstract: Field investigation on citrus huanglongbing (HGB, greening) disease caused by insect-borne liberobacter was carried out in Thailand from 1992 to 1993. The disease and its vector Diaphorina citri were present in all the citrus orchards surveyed in 12 districts throughout Thailand. Electron microscopic examination confirmed the presence of causal organisms in sieve cells of leaves with symptoms. Many viruliferous psyllas that transmitted the pathogen on young citrus seedlings were collected in HGB-infected fields. Many orchards had been destroyed due to the disease, while some pummelo orchards were still productive. HGB disease spread from infected trees to healthy pummelo trees. Sour lime, Citrus aurantifolia, was the major HGB-carrier and inoculum source. Circulation of infected nurseries or bud-sticks through growers promoted the inter-field transmission of the disease. The disease was more prevalent in flat or plain fields than in those surrounded by hills or wind breakers, due to the enhancement of vector dissemination by the wind. Rough lemon, Calamondin, Som-pan and Ladu mandarins were tolerant, while large numbers of sweet orange, mandarin and tangelo trees were susceptible. The tree growth and yields were markedly reduced by the disease when the trees were infected at young ages. There were 2 types of citrus trees in the relation of yield to canopy volume after infection, those with high and low yields. Grapefruit, some tangelos and Som-pan mandarin trees were highly productive, while large numbers of mandarin and sweet orange trees showed a low productivity. Discipline: Plant disease/Horticulture Additional key words: liberobacter, vector transmission, Diaphorina citri, host resistance

A monitoring method of land cover/land use change in Naiman, Inner Mongolia autonomous region, China using landsat data

Abstract: Naiman Qi is located on the eastern edge of the Horqin desert and has recently experienced desertification. The desertification has progressed due to overgrazing and overcutting and fixed sand dunes began to move again in this area. In this study, we intended to develop a monitoring method of land cover/land use changes using Landsat data in order to analyze the progression of desertification. First, we were able to define the area that underwent desertification (hereafter referred to as “desertified area”) using the following 3 indices; vegetation [(TM 4-TM3)/(TM4 + TM3)], structure [(TM 5 TM 1)/(TM 5 + TM 1)], and redness [(TM 3 TM 1)/(TM 3 + TM 1)]. We determined the yearly changes by superimposing the desertified areas identified based on data from different years. Second, we developed a monitoring method of land cover/land use changes to analyze the changes in the desertified areas. These methods enabled us to obtain basic information for clarifying the desertification processes. Discipline: Agricultural environment Additional key words: desertification, Landsat TM

Long Term Storage of Pear (Pyrus spp.) Shoot Cultures In Vitro by Minimal Growth Method

Abstract: Pear (Pyrus serotina cv. Senryo) shoots grown on MS medium containing 2.5% sucrose, 1 mg/l BA and solidified with 0.8% agar (control medium) were stored at 5 different temperatures for 64 weeks. The shoots did not survive at 0? for more than 4 weeks. At intermediate temperatures such as 18°C and 10°C, the survival rates of the shoots gradually declined after 16 and 32 weeks, respectively. Both survival and shoot regeneration rates were the highest in the shoots stored at 5°C under an 8 h light and 16 h dark regime. Modified media containing Paclobutrazol (PP333), Uniconazole-P (S-327D), 10% sucrose, 2% agar or 1/4 strength MS salts were more effective for 2-year storage compared with the control medium. Pyrus communis (cv. Winter Nelis) shoots stored at 5°C for 64 weeks also regenerated shoots normally. The established storage method was successfully applied to nearly 200 pear accessions conserved in the field genebank. Discipline: Biotechnology/Genetic resources Additional key words: growth retardant, low temperature, shoot regeneration, sucrose concentration JARQ 31, 1-7 (1997)

Use of Coccinella septempunctata brucki Mulsant as a Biological Agent for Controlling Alfalfa Aphids

Abstract: Ecology, mass production and release of a lady beetle, Coccinella septempunctata brucki, were investigated in Japan to use the beetle as a biological agent for controlling alfalfa aphids. In the alfalfa field, the number of overwintered aphids, Acyrthosiphon kondoi, increased on alfalfa in April and the occurrence from late April to mid-May showed a marked peak. Without C. septempunctata brucki, the reduction of alfalfa yield by aphids amounted to 40 to 70%. The overwintered adults of C. septempunctata brucki appeared in early March on the alfalfa field and began predation and oviposition. In total about 20% of the egg population developed to adults successfully. For mass production, A. pisum population was reared on Vicia faba as prey for the lady beetle. The overwintering adult lady beetle was used to obtain the eggs for mass production. The optimum development stages for release to the alfalfa fields where C. septempunctata brucki was absent were the 2nd, the 3rd and the 4th instar larvae in early March when the maximum temperature was around 10°C. The Japanese pampas grass, Miscanthus sinensis, was planted near the alfalfa field for keeping lady beetle populations in winter and summer as their overwintering and estivating sites. Discipline: Insect pest Additional key words: biological control, Acyrthosiphon kondoi

Regulation of arbuscular mycorrhiza symbiosis: Hyphal growth in host roots and nutrient exchange

Abstract: Arbuscular mycorrhizal (AM) fungi, which have often been designated as vesicular-arbuscular mycorrhizal (VAM) fungi, symbiotically inhabit plant roots. The promotion of phosphorus uptake and plant growth of host by AM fungi is now well recognized. Therefore, it is anticipated that AM symbiosis could be applied for sustainable agriculture. The author investigated the regulation of the symbiosis with emphasis placed on nutrient exchange, namely phosphorus transfer from AM fungi to host plant and reverse transfer of carbon. The following results were obtained: 1) The growth of AM fungi in host roots was regulated by the supply of photosynthates and the growth of both partners in the symbiosis was well harmonized. 2) A new method for the isolation of intraradical hyphae from host root tissues was developed. The characteristics of enzyme activities in the isolated intaradical hyphae suggest that alkaline phosphatase activity is localized in arbuscular hyphae and that glucose is one of the carbon sources from host plant to AM fungi. 3) Electrophoresis analysis showed that symbiosis-specific may originate from AM fungi. Based on these findings, the regulation of the symbiosis was discussed. Discipline: Soils, fertilizer and plant nutrition/Biotechnology Additional key words: vesicular-arbuscular mycorrhizal fungi, VAM, phosphatase, enzyme JARQ 31, 179 183 (1997)

Optimization of the Design of Subsoiling and Pressurized Fluid Injection Equipment

Abstract: There are two different design objectives for subsoilers with pressurized fluid injection, for use as pan-breakers or injectors respectively. A large soil failure is desirable when it is used as a pan-breaker and little soil failure is advantageous when it is used as an injector. This paper determines optimum shapes of pan-breaker and injector, where the draught can be reduced by injecting pressurized air (about 1·2 MPa at the air tank) from a nozzle port at the tip of the chisel. The results show that the optimum pan-breaker with fluid injection should have a rake angle of 45 to 60°, a chisel thickness of 50 × 50 mm, and a heel position at 100 mm. The optimum injector with fluid injection should have a rake angle of 90°, a shank thickness of less than 15 mm, a chisel length of 250 mm, a chisel thickness of 30 × 30 mm, and a heel position at 100 mm.

Solid-liquid separation of agricultural products using twin-screw press and electro-osmosis.

Abstract: Solid-liquid separation is one of the main processes in the agricultural and food industry. Screw pressing is one of the methods solid-liquid separation using mechanical pressing. A new type of screw press (twin screw press: screw diameter = 136 mm, L/D = 6.5, feeding rate = 50-150 kg/h) was designed with partial intermeshing and counter-rotation and tested for oil extraction from oilseeds (sunflower, rapeseed), for squeezing juice from cabbage and dewatering of soy milk residue (okara). Oil recovery with a twin screw press increased compared with the use of a single screw press. The oil expressed with a twin screw press contained a smaller amount of foreign material than single screw oil. Other properties of the oil were also satisfactory. Energy consumption of the twin screw press was the most efficient. Juice recovery from cabbage was also highly efficient (88%) with low energy consumption. Since dewatering of fluid material like soy milk residues was difficult to attain a high level of efficiency even using a twin screw press, the application of electro-osmosis was examined and found to be suitable. Discipline; Postharvest technology/Food Additional key words: waste treatment

Eco-physiological study of root lodging tolerance in direct-seeded rice cultivars

Abstract: To investigate the morphological and physiological characteristics relating to root lodging tolerance in direct-seeded rice plant, anchoring ability, root growth and its distribution to soil layers were compared among root lodging-susceptible Japanese varieties, tolerant USA varieties and Korean semi-dwarf indica varieties. Pushing resistance, i. e. the maximum resistance of plant to horizontal pushing and inclination of shoot to 45? toward the verical direction, was higher in tolerant USA varieties and Korean semi-dwarf indica varieties than in susceptible Japanese varieties. Tolerant varieties developed a larger amount of roots at full heading stage than susceptible Japanese varieties, due to the higher rate of dry matter allocated to roots in USA varieties and higher crop growth rate in Korean semi-dwarf indica varieties. Also, tolerant varieties developed a larger amount of roots in deeper soil layers than susceptible varieties. The pushing resistance was remarkably reduced when root elongation to the subsoil layers was prevented by laying an unwoven cloth between the topsoil and subsoil layers. The higher soil strength and bulk density in the subsoil layers was attributed to the higher efficiency of a unit root weight in the subsoil layers for anchoring compared with that in the topsoil layers. The above results indicate that root growth, especially root development in the subsoil layers, contributes significantly to the anchoring ability and lodging tolerance in directseeded rice plant. Discipline: Crop production Additional key words: anchoring, dry matter allocation, pushing resistance, soil bulk density, varietal difference JARQ 31,

Use, research and development of pesticides in relation to sustainable agriculture in Japan

Abstract: To promote sustainable agriculture in Japan, the use of, and research and development strategy for, synthetic pesticides were studied. The following aspects were investigated: (1) history of pesticide use in Japan, (2) benefits and risks of pesticide use, (3) changes of pesticide properties, and (4) effects of pesticides on ecosystems. Based on the results of the investigation, optimum method of pesticide use and research and development strategy to promote sustainable agriculture were proposed. Discipline: Agricultural chemicals Additional key words: benefits and risks, toxicity, behavior in environment JARQ 31, 13-20 (1997)

Separation and Identification of Desulfoglucosinolates in Japanese Rapessed by LC/APCI-MS

Abstract: To identify seed glucosinolates in Japanese rapeseed (Brassica napus L.), a method for the separation and identification of various desulfoglucosinolates that were prepared by digestion with sulfatase from glucosinolates, was developed using liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS). Desulfoglucosinolates were separated by a high-performance liquid chromatography (HPLC) system and were analyzed by APCL-MS. Nine desulfoglucosinolates were easily identified from the protonated molecular ions (M + N) +and the group-specific fragment ions (M + H C6H10O5) +. The seed of Japanese rapeseed contained the same glucosinolates as the exotic cultivars. These results revealed that LC/APCI-MS analysis is suitable for the identification of desulfoglucosinolates. HPLC analysis showed that there were remarkable varietal differences in the total and individual glucosinolate contents among the 50 main Japanese cultivars. Among these cultivars, Norin 18 showed the lowest glucosinolate content. Discipline: Plant breeding Additional key words: seed glucosinolate, HPLC, mass spectrometry, Brassica napus, oilseed rape JARQ 31, 73-80 (1997)

Structural Changes of Forage Grass Lignin by Rumen Digestion : Characteristics of Soluble Lignin Released from Timothy (Phleum pratense L.) by In Vitro Rumen Digestion

Abstract: Timothy, harvested at the seed setting stage, was subjected to 3 different treatments: (1) ball milling followed by in vitro rumen digestion, (2) ball milling followed by cellulase digestion, (3) digestion by a heifer, and then dioxane-soluble lignins (RDL, CDL and HDL, respectively) were isolated from the 3 resultant residues. RDL contained a larger amount of lignin components and smaller amounts of carbohydrate residues, and bound phenolic acids than CDL and its composition resembled that of HDL. Alkaline nitrobenzene oxidation and IR spectra showed that all the lignins consisted of guaiacyl-syringyl lignins. The molar ratio of syringaldehyde to vanillin was higher for HDL than for CDL and RDL. In gel permeation chromatograms, RDL and HDL were distributed in lower molecular weight regions than CDL. The results suggested that timothy lignin was depolymerized and the phenolic acids bound to timothy lignin disappeared by rumen fermentation. Discipline: Animal industry/Grassland Additional key words: carbohydrate, degradation, phenolic acids JARQ 31, 49-53 (1997)

Changes of ABA, IAA and GAs Levels in Reproductive Organs of Citrus

Abstract: This review provides information about the levels of abscisic acid (ABA), indole-3-acetic acid (IAA) and gibberellins (GAs) in reproductive organs and the effects of uniconazole-P application on those hormones in citrus to analyze their possible relationships with fruit set and growth. Endogenous phytohormone levels in flowers and fruitlets were studied in ‘Hyuganatsu’ (Citrus tamurana [Hort.] Ex. Tanaka), which had no parthenocarpic ability, and Satsuma mandarin (Citrus unshiu Marc. cv. Ozaki). ABA concentration in the style of Satsuma increased 6-fold from the bud to the anthesis stage. Stamens in Hyuganatsu contained higher concentrations of IAA and GAs than in Satsuma. Immediately after pollination, Hyuganatsu showed peaks of ABA and IAA concentrations in fruitlets and parthenocarpic Satsuma also showed smaller peaks of ABA and IAA concentrations. Parthenocarpic fruitlets contained higher concentrations of GAs than pollinated fruitlets after fruit-set. ‘Sepals’ which included floral disks, sepals and receptacles in both setting types contained higher concentrations of ABA than in the nonsetting type, suggesting that ABA in ‘sepals’ plays a positive role. ‘Sepals’ in both setting types contained higher concentrations of IAA after fruit-set, suggesting that IAA from ‘sepals’ may hinder fruitlet abscission. Uniconazole-P, a GA biosynthesis inhibitor, markedly stimulated fruitlet abscission in Satsuma and increased 4-fold the concentration of endogenous ABA in fiuitlets. Discipline: Horticulture Additional key words: abscisic acid, gibberellin, indole-3-acetic acid, fruit drop, fruit-set

Central Nervous Disorder of Calves Consuming Colostrum Containing 4 Methyl-Imidazole or Colostrum from Cows Fed Excess Ammoniated Hay

Abstract: Holstein cows were fed fresh hay with a high sugar content and treated with 6% liquid ammonia as their main ration, for 3 weeks before and after calving. Their colostrum (test milk) was compared to normal colostrum to which 4 methyl-imidazole (4MI milk) had been added, and to normal colostrum lacking 4MI (control). Ten male Holstein calves (2 hours to 12 days of age) were used in this trial. Following the consumption of test milk, 4MI milk or normal colostrum, the symptoms of a central nervous system disorder were compared. Additional parameters monitored included heart function analyzed through electrocardiogram (ECG), auditory brainstem response (ABR), hematological and blood chemistry profiles. Two calves became febrile, hyperexcitable, and displayed an abnormal circling behavior within 2 days after the consumption of test milk. ABR decreased and disappeared intermittently. Four out of 6 calves given 4MI milk developed similar signs and showed a similar disappearance of ABR, while 2 older calves (6 and 12 days) did not develop fever or did not exhibit circling or abnormal ABR. Nearly all the experimental calves showed an elevation of blood pyruvate and lactate concentrations coinciding with the onset of illness. No remarkable changes in other blood components were detected. The autopsy did not reveal any pathological changes. These findings suggest that the age of the calf is related to the toxicity of a compound and in this experiment therefore affected the comparison of clinical signs induced by either 4MI milk or test milk. Discipline: Animal health Additional key words: auditory brainstem response (ABR), electrocardiogram, neurotoxicity, feed poisoning JARQ 31, 225-231 (1997)

Characteristics of wild silk fibers and processing technology for their use

Abstract: The physical properties and processing technology of wild silk fibers, yarns and fabrics have been studied for the promotion of new uses of silk by developing novel fabrics made of fibers of wild silkworms different from those of the domesticated silkworm (Bombyx mori). Although wild silk fibers show advantages such as thickness, bulkiness, compressive elasticity, resistance to chemicals, they display many defects, including shrinkage with hot water, poor cohesion, development of bright specks in the yarn, low dyeing ability, etc. However, we succeeded in pro by combining mori silk with wild silk fibers, and by effectively utilizing the latter’s characteristics for a wider demand of silk products. The mixed twisted yarns produced by the combination of wild silk fibers with mori silk with limited shrinkage enabled to improve the dimensional stability of wild silk fabrics. Also, the use of thick yarn enabled to prevent the occurrence of bright specks. The use of acid milling dyes or reactive dyes for wild silk yarns led to the induction of dark shades and rich, fast colors, especially since it had been hitherto difficult to use reactive dyes for mori silk products and wild silk fabrics. Discipline: Sericulture/Agricultural environment Additional key words: wild silk, physical property, silk fabrics, dyeing JARQ 31, 287-294 (1997)

A New System for the Detection of Phytopathogenic Phytoplasmas Using PCR (Polymerase Chain Reaction) and Laser Stylectomy

Abstract: A new system for the detection of phytoplasmas in both rice and mulberry plants using PCR assay and laser stylectomy was investigated. Pure phloem sap was collected in a capillary tube from plants with phytoplasma diseases using laser stylectomy (insect laser technique). Direct detection of phytoplasmas in the phloem sap was attempted using the polymerase chain reaction (PCR). The phloem sap was heated at 95°C for 5 min or not heated. and used directly as the DNA template for PCR amplification. Two sets of oligonucleotide primer pairs were used to amplify the target DNA fragment (length, 1.37 kb and 0.75 kb) from 16S rRNA genes of phytoplasma. The predicted band was observed for almost all the heated or unheated samples collected from diseased plants, whereas no band was detected in the samples collected from healthy plants. Each of the amplified PCR products was found to be the target DNA from 16S rRNA genes of phytoplasmas based on the analysic of their restriction enzyme digestion and determination of the DNA sequence. Thus, the new detection system using both laser stylectomy and PCR assay was found to be sensitive and specific. Discipline: Plant disease/Biotechnology Additional key words: rice yellow dwarf disease, mulberry dwarf disease, diagnosis, mycoplasmalike organisms JARQ 31, 281-285 (1997)

Comparison of Resistance to Theileria sergenti Infection between Holstein and Japanese Black Cattle under Grazing Conditions

Abstract: To analyze the resistance against Theileria sergenti infection in Holstein and Japanese Black cattle under field conditions, clinical, hematological and parasitological findings in these breeds of cattle that were grazed in the same pasture were examined during the grazing period. Holstein cattle showed a higher level of parasitemia than Japanese Black. With the progression of parasitemia, packed cell volume (PCV) decreased in both breeds and the minimum value of PCV recorded in Japanese Black was higher than in Holstein. The daily gain rate was higher for Japanese Black cattle than Holstein. These results suggest that the Japanese Black cattle display a higher resistance to T. sergenti infection than the Holstein under field conditions, based on a previous infection test carried out under experimental conditions without external factors. Discipline: Animal health Additional key words: daily gain (DG), ELISA, packed cell volume (PCV), piroplasm JARQ 31, 219-223 (1997)

Switch in searching behavior and stimulus causing host examination by Trichogramma chilonis Ishii, an egg parasitoid of Plutella xylostella L

Abstract: The locomotory response of walking Trichogramma chilonis female to the contact of scales and secretions of host moth, Plutella xylostella, and elicitation of oviposition behavior were observed. In response to a contaminated Sealon film with host moth scales and secretions, a T. chilonis female exhibited a response involving walking at a reduced speed. T. chilonis female remained during a much longer period of time on a contaminated Sealon film than on a clean one. Also moth scales and/or secretions elicited the oviposition behavior of T. chilonis females. Discipline: Insect pest Additional key words: biological control, moth scales and secretions

Current Conditions of Reservoir Sedimentation in Irrigation Dams in Japan

Abstract: Field data of 53 high dams were comprehensively analyzed to clarify the current conditions of sedimentation in irrigation dams in Japan compared with dams for other purposes. At first, it was shown that the CI ratio was an important index which markedly affected the sedimentation factors, the stages of sedimentation and the trap efficiency. Next, the sedimentation characteristics of the irrigation dams were analyzed and clarified by using the CI ratio. Main results obtained are as follows: (1) The annual sediment deposit rate of irrigation dams is relatively smaller than that of power generation dams in general, implying that the locations of irrigation dams are usually suitable for preventing the occurrence of sedimentation problems. (2) The specific sediment rate of irrigation dams is relatively large in general. Accordingly, it is necessary to investigate the factors which cause the increase of the specific sediment rate rather than the sediment deposit rate in irrigation reservoirs. Discipline: Agricultural engineering, irrigation, drainage and reclamation Additional key words: annual sediment deposit rate, CI ratio, specific sediment rate, trap efficiency JARQ 31, 29-34 (1997)

Study on Groundwater Flow System Using Underground Temperature Survey Method

Abstract: Groundwater flows which contribute significantly to slope failure are concentrated in highly permeable layers or continuous fracture zones and are referred to as groundwater vein streams. The underground temperature survey method is a simple technique for measuring the temperature at a depth of 1 m from the ground surface. The method not only enables to locate the groundwater vein streams, but also to determine the radius and the depth down to their center assuming they have a cylindrical section. A distance of about 6 m or less between the measurement points is essential for the accurate estimation of the radius and depth of groundwater vein streams. On the other hand, measurement conducted at 20 m intervals is sufficient for approximate location, and the difference between the temperature at a measurement point and the average temperature of neighboring measurement points provides a useful clue for the detection of a temperature change associated with ground water vein streams without considering influences of the topography and land cover. An underground temperature survey was conducted in a landslide area in Niigata prefecture for the study of the groundwater flow system. The depth of the groundwater vein stream estimated by this method agreed well with that determined by conductivity logging, permeability test and temperature logging conducted in a boring hole. Discipline: Irrigation, drainage and reclamation Additional key words: boring, land conservation, landslide JARQ 31, 117-123 (1997)