Vol. 10 No. 1 (2012)

A research on natural enemies of aphids on citrus fruits was conducted in citrus growing district  of Chuong My, Hanoi to examine major morphological and biological features of the predatory fly  Dideopsis aegrota Fabricius. 13 species of natural enemies of aphids were found in 2011 spring,  including 6 species of ladybird, 1 species of ants, 1 species of parasitoid wasp, and 5 species of  predatory flies. Two predatory flies Episyrphus balteatus Larvae and Dideopsis aegrota Fabricius and  the lady beetle Menochilus sexmaculatus Fabricius are suggested to be the main natural enemies of  aphids. The predatory fly Dideopsis aegrota Fabricius was recently discovered in Hanoi. Dideopsis  aegrota Fabricius has large body size; adults range from 13.16 ± 0.36 mm in length and from 4.85 ±  0.19 mm in width with wingspan of 26.16 ± 0,68 mm. Its life cycle ranges from 24,60 to 25.30 days and  longivity from 33.81 to 34.19 days. The larval stage of a predatory fly prey consumes 214.20 to 220.70  individuals of the Green citrus aphid Aphis citricola Van Der Goot. The number of prey consumed per  day was recorded

In order to help farmers adopt organic foliar feririlizers available a comparative study on their effectiveness was conducted in Spring and Summer rice seasons on Red River Delta’s alluvial soils at Hanoi University of Agriculture. Research results indicated that for Bac Thom 7 variety, application of 12 tons and 10 tons of compost in spring and summer season, respectively, plus 1500 kg of Sông Gianh microbial organic fertilizer ha-1, together with spraying organic foliar fertilizer increased growth significantly in comarison with control (no foliar fertilizer). Among foliar fertilizers used, viz. Chelax Lay O, CHELAX Sugar Express, CHELAX Rice and combined nutrients, Chelax Lay O was most effective to the growth and productivity, followed by the combined nutrients. The corresponding economic return amounted to VND 97.3 mil. and VND 104 million ha-1, year.

The objective of this study was to analyze genetic diversity of 64 rainfed rice accessions by detecting the presence and degree of polymorphisms of simple sequence repeat (SSR) markers. Thirty-four SSR markers were used. There were eight SSR markers that do not show polymorphism and two markers are monomorphic. A total of 90 alleles were detected at twenty-four SSR marker loci with average 3.75 alleles per locus. With the genetic similarity coefficient of 0.65 the rice accessions were grouped into 7 main clusters. Most of rice accessions were found in two groups toghether with two controls CH5 and LC93-1. Information of SSR marker polymorphisms are useful for drought tolerance breeding in rice.

Sesame (Sesamum indicum L.) is an industrial crop for oil production with high nutritive and economical values. But, like other plants, sesame is attacked by many insect pests. There are not many articles on insect pest diversity in general and leaffolder in particularly elsewhere. The survey results in 2010 and 2011 showed that there are 16 insect pests on sesame during 2010 and 15 species appeared during 2011. Sesame leaffolder (Antigastra catalaunalis Dup.) is one among the important species affecting yield significantly. The density variation of leaffolder/webber during 2010 spring season was less than in summer season (5.6 ind./m2 and 28.6 ind./m2 at Thach Bang village). The population dynamics of sesame leaffolder during summer season of 2010 at three villages (Thach My, Thach Chau and Thach Bang) was similar and rather high. The sesame leaffolder appeared and damaged on sesame plant from early stage till pod maturity. In 2011, A. catalaunalis appeared later and thedensity was lower than that in 2010. The highest density was 5.4 ind./m2 and 1.8 ind./m2 in spring-summer and summer-autumn season, respectively, at Thach Bang village. The density of sesame leaffolder in summer-autumn 2011 at Thach Chau was higher than at Thach My and Thach Bang village.

Since 2009 up to date, over 7,000 specimens of coffee scale insect infected with mycopathogens in three provinces in the Central Highland, i.e. Dak Lak, Dak Nong, and Gia Lai were collected, among these 360 specimens were selected for isolation. 25 strains of insect fungi were identified based on morphological and molecular characteristics and 6 parasitic species were identified including: Beauveria bassiana, Metarhizium anisopliae, Cephalosporium lanoso-niveum, Cordyceps nutans; Toxicocladosporium sp., and Paecilomyces cicadae. Virulence test by in vitro evaluation of  extracellular enzyme activities showed that 8 strains as MR3, MR4, MR8, MR9, BR5, BR11, BR13 and BR16. These strains showed high potential for mass product to control scale insect on coffee. The optimal temperature for growth and development of these strains ranged from 25 to 280C. At 300C fungal strains of BR2, BR4, BR7, BR10, BR11, BR13, and BR16 can grow well. The best substrate for mass product of these strains was rice. Application of bio-products under laboratory condition showed that highest control efficacy was 77.78% with strain BR5, followed by 74.45% with strain MR4.

Stenomesius sp. (Eulophidae) is the most frequently occurring parasitoid species on green bean leaffolder Omiodes indicata F. Life cycle of Stenomesius sp.  was about 11.11 ± 0.26 days at temperature of 25.4 ± 1.7°C  and 89.0 ± 3.5% relative humidity, in which the development of egg, larva, pupa and adult were 1.1, 4.39, 4.76 and 0.86 days, respectively. Food supplement showed a clear effect on adult longevity as well as oviposition. Adult’s longevity of wasp at each treatment (pure honey, 50%, 10% honey solution and water) was 12.75, 7.75, 3.13 and 2.38 days. Oviposition capacity at each treatment was 85.5, 39.3, 15.5 and 12.5 eggs per female on host individuals of 9.75, 5.25, 2.25 and 2.0 individual/female respectively. The percentage of adult emergence of Stenomesius sp. was very high in laboratory conditions (87.8 – 94.1%) as well as those pupae collected from green bean field (88.5 – 92.8%) in 2010 spring season. The sexual ratio of Stenomesius sp. was more on the side of female, 1male: 3.8-4.95 females from those pupae obtained in laboratory and 1male: 3.3-4.4 females of those pupae obtained from field.

A field trial was conducted in Spring season in Y Yen,  Nam Dinh to study the effect of hill spacing and number of plant per hill on the growth, development and pod yield of groundnut cv. L23. The three hill spacings were 25, 35 and 45 hill/m2 and three number of plants was 1, 2 and 3 plants per hill. The experiment was laid out in split-plot design with the main factor being hill density and number of plants per hill as subfactor. The results showed that hill density of 35 plants/m2 with 1 plant per hill or 25 plants/m2 with 2 plants per hill gave the highest yield compared  to 45 plants/m2. Two plants per hill gave significantly higher yield than that of one plant and three plants per hill. The highest economic return (33.985.000 VND/ha - 34.227.000 VNĐ/ha) was obtained in the treatment of 1 plant/hill with 35 hill/m2 and 2 plant/hill with 25 hill/m2. Therefore, a density of 25 plants/m2 with 2 plants per hill or a density of 35 plants/m2 with 1 plant per hill was suggested as the promising practice for the improvement of yield in groundnut cv. L23 in Spring season in Y Yen,  Nam Dinh

Drought is the main constraint to rice production under rainfed condition. With the aim of selecting rice varieties suitable for rainfed cultivation, the present experiment was carried out to evaluate characteristics related to drought tolerance and yield of 19 upland rice varieties collected in Tay Bac in comparison with the control CH5 at Tay Bac University.  Drought tolerance of rice varieties was evaluated at the germination stage using KClO3 solution and under natural rainfed condition in Thuan Chau, Son La. The results showed that in the germination and seedling stage most of the upland varieties exhibit higher drought tolerance than the control in terms of  germination percentage in KClO3 solution (G2, G4, G6, G9, G10, G18) and seedling and root growth (G2, G8, G9, G10, G14).  Under rainfed condition, upland rice varieties showed moderate to high drought tolerance (1 to 3  in IRRI scoring system).  The grain yields of the upland varieties range  from 1.28 to 2.23 tons per hectare, a yield reduction by from 14.75 to 37.51 percent compared to irrigated condition. In contrast, the control showed yield decrease by 37.,06 percent. The following upland rice varieties, G2, G4, G9, G10, G18 were identified as having higher yield in rainfed condition at Thuan Chau, Son la.

This study was conducted to identify optimal rate of NPK (15:10:15) fertilizer applied to Tay Bac’s indigenous cucumber at the Faculty of Agriculture and Forestry, Tay Bac University. There were 6 treatments with 6 NPK (15:10:15) levels and a control without NPK-application. The experiment was laid in Randomized Complete Block (RCB) design with three replications.  Evaluation parameters were growing period, growth, development, pest and disease damages, yield components, yield, quality, efficiency of NPK application, and economic efficiency. The results showed that applying 800 kg/ha of NPK fertilizer (15:10:15) to Tay Bac’s indigenous cucumber was most suitable for plant growth, development and gave the highest individual productivity (4.34 kg/plant), highest harvested yield (90.12 ton/ha), high fruit quality, and highest fertilization and economic efficiency with net profit of VND 296.22 million  per hectar.

A pot experiment was carried out to study effect of four water deficit levels, viz. serious water deficit (SD, 35% ~ 45% θf, θf  field water capacity), medium water deficit (MD, 45% ~ 55% θf), mild water deficit (LD, 55% ~ 65% θf) and normal irrigation (CK, 65% ~ 80% θf) at the seedling – early joining stage, later joining – booting stage and booting – flowering stage of maize crop, on the photosynthetic rate, yield and water use efficiency of sticky maize. The results showed that water deficit decreased  photosynthetic rate, transpiration rate, dry matter accumulation and  grain yield at  all  growth stages of corn plant.  In comparison with the well-watered control, SD significantly decreased both dry matter accumulation and yield. However, LD and LD  did not significantly  decrease yield but reduced  total water consumptions by 10.75~19.85%.

The experiment was conducted in Nghia Dan, Nghe An to select varieties with high edible biomass yield and quality of forages used as feeds for dairy cows. 15 varieties were tested including 8 varieties of gramineae, Brachiaria Mulato II, Panicum maximum TD58, Panicum maximum cv., Panicum maximum Mombasa, Pennisetum purpureum cv., Paspalum atratum, Sorghum bicolor cv. and maize C919 and 7 varieties of legumes, Stylosanthes guianensis Ubon, Stylosanthes guianensis CIAT184, Croatalaria; Burgady bean; Sardy Ten, Ebody Cowpea and Leucaena leucocephala. The testing varieties were planted in a randomized complete block design (RCB) with three replicates on moderately acidic soils but rich in phosphorus in the area with annual rainfall of about 1600mm. Six varieties, namely Mulato II,  P.maximum Mombasa, P.maximum TD58, P.maximum cv., P. purpureum cv., Paspalum atratum,  produced 43.7 - 61.1 tones dry matter/ha/year. The green forage yield in dry season accounted for 37-41% and crude protein yield was 2.3 – 7.7 tones/ha/year. Two promising  leguminous varieties, Stylossanthes Ubon and Stylossanthes Guiassinensis CIAT 184 produced 27.05 -28 tones dry matter/ha/year, 3.9 – 4.5 tones/ha/year of crude protein. Seven of 15 varieties tested were found to possess high productivity and quality and they can be used as feed for dairy cows in Nghia Dan, Nghe An.

The present experiment was conducted to determine the effectiveness of fungal antagonist formulations derived from Trichoderma viride (CP2, CP3 and CP4) in controlling some soil-borne fungal diseases of potato, ground-nut and soybean. The T. viride  was isolated from the soybean soils at Phu Thi – Gia Lam and some other locations.  For potatoes, tuber treatment  with 50 g CP2,  200g CP4 and mixed with 100 kg manures per 10 kg tubers  gave the highest control efficiency against southern blight disease (58.3%),  For soybean, spraying CP3 at a concentration of 15g in 3 litters  per 30 m2 at seedling stage gave good control efficacy after 21 days (75.5% for the damping-off  and 67.7% for the southern blight ). Peanut seed treatment with 5g CP3 or CP2 per kg seeds gave good control of damping-off disease (80,8% and 79.4%, respectively.  In field demonstration plots potato, soybean and peanut yield increased by 9.7% , 12.2 %. and 15.6 %, respectively in comparison with the control.

The application nitrogen fertilizer aim to define sensible nitrogen dose for tuberous root yield of mondo grass on Ferralic Acrisols at Phu Tho province. The application nitrogen dose change from 30 to 50 kgN/ha + 10 tons organic fertilizer +  30kg P2O5 + 30kgK2O/ha. Mondo grass was researched on   growth of foliate, root and tuberous root yield.  Results showed that:  the dose of nitrogen fertilizer applying on  30kg N + 10 tons organic fertilizer +  30kg P2O5 + 30kgK2O/ha  achieved the max tuberous root yield and economic effectivity. The tuberous root yield of mondo grass achieved 33,08 ton/ha. The income achieved  850,792 million VND/ha/3 years and investable effectivity of nitrogen fetilizer - 38,52 fold.

This study aimed to clarify the scientific name of a common grasshopper species belonging to the Hieroglyphus Krauss (1873) genus, which causes serious damage to plantation in Hoa binh province since 1997. Fifty individuals of this species were reared singly at 250C ambient temperature condition for their morphologic characteristic observation and description. These characteristics were collated to those described in taxonomic system of Mistshenko (1952). Our study has confirmed that the species studied is H.tonkinensis Bolivar (1912). Our results of survey on the grasshopper species during 2010 and 2011 at 3 epidemic sites in Hoa Binh province at coordinates of 20053’34”N, 105014’56”E; 20045’53”N, 105015’49”E and 20041’39”N,  105013’44”E indicated that the most common grasshopper species in this province is H.tonkinensis Bolivar (1912). During survey periods this species occurs with high frequency of above 40% and may account for 87% of the population.

In recent years, the new rice two-line hybrids developed in Vietnam have been growing widely in Summer as well as in late Spring seasons, because of the high yield, good quality and short growth duration. The Hybrid rice Technology Division has continuosly improved parental lines for better quality, plant type and lodging resistance.. TH7-5 (T7S/R5) is a new two-line hybrid rice variety with short growth duration (107-110 days in Summer crop and 120-125 days in Sping crop). TH7-5 has intensive plantype, thick and stirl culm, good lodging resistance with long errect and dark green flag leaf color, big panicle and high grain number and high yield (5-7,5 tons/ha), good grain quality, blast resistance, moderate pest resistance(slightly susceptible to blast and bacterial leaf blight). TH7-5 is suitable to the late Spring and early Summer crop in the northern provinces of Vietnam. T7S is a TGMS line, that has been selected from the combination T1S-96/Huong125S, with intesive plant-type, high out-crossing rate and moderately sensitive to GA3. The restorer line R5 is an aromatic line selected from the combination R3/Huong com. The hybrid seed production protocol has been establised and used for seed production trial with the yield 1.83-2.68 tons per hectare.

This research was conducted to indentify the stage of applying pressed and slow-release organic mineral granular fertilizer to help increase yield of maize grown on sandy soils in Quang Binh. The fertilizer granules that weigh 1.8 g each was applied for corn in spring 2010. The experiment was arranged in a Randomized Complete Block Design (RCBD) with 3 replications with 6  application timings  and frequency. The results showed that 3 applications including basal and two times of top-dressings at 3-4 leaf and 6-7 leaf  stage gave the highest yield.

Myogenin is one of genes which affect for performance and meat quality traits in pigs. Based on traits for measured-chemical composition, pH value and driploss of loin and ham as well as detected-MyoG genotypes (3’-UTR, MspI) in a crossbred population of Yorkshire x Landrace, polymorphic association between MyoG genotypes with the traits was analyzed. Significant difference between MyoG genotypes for ash and pH60 value of loin was found. There was no significant effect of MspI polymorphic sites on other chemical compositions (dry matter, crude protein, ether extract) and driploss of loin and ham.

A study was conducted in 5 districts of Hanoi, Haiduong and Namdinh provinces. It was found by fecal examination that the prevalence of Clonorchis sinensis infection in dogs and cats was 8.53% and 16.66%, respectively. Whereas, results of partial necrosis showed that the prevalence was 14.76% and 23.59%, respectively. The older the dogs and the cats were, the higher was the prevalence. The prevalence of infection in confined dogs and cats was lower than that in wandering ones. There were also 7 larvae-infected fish species determined with the highes prevalence in silver carps (53.33%) and the densest larvae distribution noticed in the muscle (72.05%). the highest infection intensity in selver carps was 45.5 larva per carp. The interviews revealed 19.39% people eating raw-fish.

Comparative study on utilisation efficiency of inclusion of sesame meal, rice bran and maize meal in common carp feeds was conducted with fish of 60g initial body weight. Three isoproteic (31%) and isoenergetic (15.5 MJ/kg) experimental feeds (TAvừng, TAcám gạo,TAngô) were formulated. It was found that the average daily gain (ADG) ranged from 3.1 to 3.8 g/fish/day, protein efficiency ratio (PER) varied from 1.61 to 1.95 and protein retention (PR) efficiency was between 31.11 and 38.76. All the three indicators (ADG, PER, PR) were highest in fish fed the diet containing sesame meal (TAvừng), followed by fish fed TAngô and the lowest was rice bran diet (TAcám gạo). Feed conversion ratio (FCR) ranged from 1.63 to 1.92. The cost of raw materials to achieve 1 kg of fish weight gain ranged from 22.0 to 26.5 thousand VND/kg. FCR and the cost of raw material to achieve 1 kg of fish weight gain were lowest in fish fed TAvừng and highest in fish fed TAcám gạo. The results of the present study indicated that sesame meal gave the highest utilisation efficiency, followed by maize meal and then rice bran. The conclusion should have an important practical significance in the selection of raw materials for common carp feed formulation, which would help to lower production costs and improve economic profits.

A feeding trial was carried out to determine effects of replacement of complete pellets with water spinash (Ipomoea aquatica) at different levels in the diet on feed utilization, growth rate and carcas composition of exotic rabbits. A total of 30 growing New Zealand White rabbits at 1.5 months of age were randomly divided into 5 groups to be fed diets in which 0, 25, 50, 75, or 100% complete pellets was replaced with water spinach. Results showed that intake of water spinash increased accordingly with the reduced levels of complete pellets, making the total feed intake almost unchanged (P>0,05). Total tract digestibility was not affected with the different levels of replacement (P>0.05). However, the average daily gain (ADG) and feed conversion ratio (FCR) tended to decline when the level of water spinash was increased in the diet, especially for those fed totally on water spinash. Nevertheless, the ADG and FCR were almost unaffected (P>0,05) when only 25% complete pellets was replaced with water spinash. Dressing percentage and proportions of fore legs, rear legs, and loin in the carcass were not significantly influenced by the replacement; whereas, the proportion of visceral organs increased with the increased levels of water spinash in the diet (P<0.05). It is therefore suggested that growing New Zealand White rabbits should not be fed totally on water spinash, but complete pellets can be replaced up to 25% with it as this level of replacement appeared to result in better economic efficacy compared with 100% complete pellets in the diet.

Paddy rice cultivation is a cause of methane emission, which belongs to green house gases.  This study was carried out to investigate methane emission situation of rice paddy (at fully initiation stage) at some provinces of the Red river delta (Hai Phong, Thai Binh, Nam Dinh, Hai Duong, and Hanoi). 10 samples were taken in each province at the summer rice season 2010. Results showed that the average methane flux of 5 provinces was the lowest in Thai Binh (39.5 mg mgCH4/m2/h) and was the highest in Nam Dinh (61.3 mgCH4/m2/h). The methane flux in Hai Phong varied from 31.4 to 69.9 mgCH4/m2/h, Thai Binh varied from 32.1 to 60.3 mg mgCH4/m2/h, Nam Dinh varied from 40.7 to 94.2 mgCH4/m2/h, Hai Duong varied from 30.9 to 84.3 mg mgCH4/m2/h Hanoi varied from 33.1 to 57.9 mg mgCH4/m2/h. In the summer rice season 2010, methane flux reached the highest value at 5 weeks after transplanting, which was 72.3 and 66.0 mg mgCH4/m2/h in experiment sites of Hai Duong and Hanoi, respectively. Then it gradually reduced to the end of growing season. In the spring rice season 2011, methane flux gained its peak at 9 weeks after transplanting, which was 53.6 and 44.7 mg mgCH4/m2/h at 2 sites, respectively, and it was lower than methane flux of the summer season 2010. The research results of correlation between methane flux with soil properties showed that methane flux was tightly correlated inversely with pHKCl in Hai Phong soils (r = -0.82), with available Mn and Eh in Thai Binh, Hai Duong, and Nam Dinh soils (r from -0.55 to -0.85), and correlated positively with organic matter content in Hanoi soils (r=0.6).

Thí study was carried out to determine soil properties and for soil mapping of Ba Lat estuary. The main methods applied are soil servey, soil analysis, and soil classification according to FAO. The results showed that soils of Ba Lat estuary, Giao Thuy district were divided into 3 soil groups with 5 soil units, including 5 soil sub-units. Salic Fluvisols group has largest area of 7,498.01 ha, accounts for 77.61% of total surveyed area and nearly 50% of total natural area. Typical character of salic fluvisols of Ba Lat estuary, Giao Thuy district is various soluble salt concentration. More than 71% of salic fluvisols has high salinity which has total soluble salt greater than 0.5%; the rest has medium and low salinity, with total soluble salt less than 0.5%. Salinity comes from chloride. Total concentration of substances varies from medium to rich. Fluvisols group has only 1,859.16 ha, accounts for 19.24% of total surveyed area. Fluvisols of Giao Thuy district is typical with light to medium soil texture, rich total nitrogen and total phosphorous, medium potassium. Acidity from light acid-medium to light alkaline. Entire area is slightly saline. Arenosols group has smallest area of 303.71ha, accounts for 3.14 of total surveyed area or 2% of district’s total natural area.  Arenosols of Ba Lat estuary, Giao Thuy district has very light soil texture (the main content is sand), medium acidity, poor nutrients and low cation exchange capacity, normally less than 3 meq/100g soil.

  Membrane fouling is one of the great challenges for application of membrane bioreactor technology to wastewater treatment. Aeration system is a key factor to avoid the sludge cumulated on the membrane surface. The effects of aeration intensity on the cross flow velocity and membrane fouling were determined in this study. As a result, the cross flow velocity was increased with increasing in aeration intensity. When aeration intensity was increased from 0.014 to 0.069 L/cm2/min, the cross flow velocity was increased rapidly. However, it was almost unchanged when aeration intensity was higher than 0.069 L/cm2/min. The transmembrane pressure was also increased quickly when the cross flow velocity was lower than the critical velocity (30.5 cm/s). When the cross flow velocity was higher than 30.5 cm/s, the transmembrane pressure was increased negligible. Therefore, the air flowrate should be controlled to make sure the cross flow velocity to be higher than the critical value. This will prevent the membrane fouling and help the system to be operated longer.

This study aims to estimate the air pollutant emissions into the asmostphere caused by open rice straw burning after rice crop harvest in the Red River delta. The results revealed that the emission of CO2 is the largest, between 1.2 – 4,7 million tons per annum when the burning rate varies from 20-80%. The emission of CH4 is between 1.0 – 3.9 thousand tons per year while CO pollutant emission is between 28.3 – 113.2 thousand tons per year. The GHG emission from open rice straw burning in the Red River delta could cause the environmental damage from 19.05 to 200.3 million USD per year depending upon on open rice straw burning rate (20-80%) and on the market price of CO2 emission right in the world. Enhanced use of rice straw for mushroom production, biofertilizer,and  power generation... could be the relevant ways that should be studied for mitigating the open rice straw burning in the Red River delta in the coming time.