Vol. 17 No. 12 (2019)

Tetranychus urticaeKoch (Acari:Tetranychidae) is a dangerous peston manycropsin Vietnam and worldwide. The objective of this study wasto find outthe biological and ecological characteristics of this harmful two-spotted spider miteas a basis to launch the effective pest managing strategies in the future. In this study, the development time, reproduction and population growth of two-spotted spider mite reared on the green bean variety TN38 and cucumber F1 (VA.103) were investigated at 23.5C. Results showed that the total immatures of male T. urticaewere not significantly different when reared onthebean and cucumberfor11.93 days and 11.73 days, respectively. However, the life cycle of female T. urticaereared on bean (13.69 days)wassignificantly shorter than its rearingon the cucumber (15.65 days). The oviposition rate and total number of eggs laid by the females fed on the bean (6.00 eggs/female/day and 62.69 eggs/female, respectively) were significantly higher than that of the female fed on cucumbers (3.13 eggs/ female/day and 29.35 eggs/female, respectively). The generation time (T) of the two spotted spider mite reared on bean (17.72 days)was significantly shorter than that on cucumbers (19.98 days). The net reproductive rate (R0) of the female fed on bean (45.02 females/female) was much higher than that of females reared on cucumbers (21.97 females/female). The intrinsic rate of natural increase of T. urticaeon bean was 0.210 which showed asignificantly higher than in cucumber (0.150).

The objective of this study was to purify IgY antibodies from chicken egg yolks and apply them for prevention and treatment of Gumboro disease in chickens. In this study, ISA Brown layers of 16 weeks old were used for hyper-immunization to produce eggs with high antibody titers. The immunization results showed that IBD antibody titer sharply increased, especially after hyper-immunizing. The highest titer in the serum samples was obtained at 8 weeks post first vaccination (S/P value was 2.86 ± 0.068). Similar with sera, titter of IBD antibody also raised in eggs, S/P value of IgY-antibody was 2.56 ± 0.111, S/P value of purified IgY from the appropriate yolk was 2.60 ± 0.052. The antibody titer of purified IgY product was stable at 4C with 0.1% sodium benzoate added. The treatment results of chickens that were experimentally infected with gumboro virus showed that 10/10 chickens previously received IgY antibody and 9/10 chickens were treated with IgY antibody after challenging gumboro virus were survived and recovered while 9/10 chickens in the control group that did not receive IgY antibody before challenging test were died.

The study aimed to identify some epidemiological and clinical characteristics of Strongyloidosison dairy cow. By using theepidemiological methods, 809 fecal samples were collected for examinationby floatation method. The results indicated that the infection rate of Strongyloidesspp. at 5 farms in Mocchau dairy cow breeding joint stock company was 26.58%. Dairy cow infected Strongyloidesspp. with all ages, the infection rate of Strongyloidesspp. reduced according to the age (60.48% in dairy cow under 6 months old and decreased by 7.78% in dairy cow over 2 years old. Strongyloidosiscould occur in all year round, although the infection rate of Strongyloidesspp. in February and March were higher than December and January, respectively. The infection rate of Strongyloidesspp. at households (35.48%) were higher as compared with industrial farms (23.56%). The infection rate of Strongyloidesspp. in dairy cows with diarhhea (58.29%) was higher than dairy cow with normal feces (17.04%). The infection rate of Strongyloidesspp. showed clinical sign 17.67% with the main symptoms as scraggy, ruffled, sticky feces in the anus, loss of appetite, non-appetite, loose stools.

The current research was conducted on lekima (Pouteria lucuma)fruit in order to produce a new product in powder form which is rich in antioxidants, vitamins, especially beta-carotene. The product attained in this research has a high potential application in food industry as a functional ingredient or a natural food coloring powder, and added value to the lekima farming. The fruit flesh was dried at 60oC in 8 h, then grounded into a very fine powder and packed in three layers packaging material. The lekima powder includes vitamin C content of 2.5 mg/100g dried matter (DM), totalcarotenoid of 1.33 mg/100g DM, and beta carotene content of 0.3 mg/100g DM. The product meets the food safety standard of the Ministry of Health.

In this study, based on the first shear deformation theory (FSDT),a finite element model using a 3D-Degenerated shell element is developed for dynamic analysis of functionally graded spherical shell panel in the thermal environment. The modulus of elasticity is assumed to be temperature-dependent and graded in the thickness direction according to the simple power-law distribution,while the Poisson factor is assumed to be constant and the temperature is assumed to be nonlinear variation in the thickness direction. The numerical results are also compared with the results available in the literature to validate the present model. On the other hand, the effect of material parameters, geometric dimensions, boundary conditions; damping factor; ratio of forced frequency/natural frequency (ratio Ω/) on the dynamic behavior of FG spherical shell panel in the thermal environment are also investigated in detail and some useful conclusions are drawn.

Export of fruit and vegetables are considered as one of Vietnam's promising sectors and has been gaining success in some important markets, such as Japan in recent years. This paper assesses the current situation and potential of vegetables and fruit export from Vietnam to the Japanese market using the secondary data of International trade centre (ITC) and the General Department of Vietnam Customs. The results showed that although Vietnam's vegetable export market share in the Japanese import market has only accounted for about 1,2%, it has increased steadily over years, with the advantage of products from the tropics. Revealed Comparative analysis shows that overall vegetable and fruit export from Vietnam has an advantage over the years. Factors affecting Vietnam's vegetable and fruit exports include increased market demand, competition from exporting countries, free trade agreements, product quality issues and conformity with consumer demand, post-harvest losses and high logistics costs. Several recommendations to promote vegetable exports to Japan are proposed accordingly.

Da Bac district, Hoa Binh province has started implementing the PFES policy since 2013. PFES is a mandated payment program from users of forest environmental services (FES) to service providers without using the state budget. Based on secondary and primary information gathered from various stakeholders related to PFES, this paper aims to assess the success and shortcomingsof PFES in Da Bac district.The results show that in2017, the area of ​​forest protected by using PFES money has reached 90,35% of district's forest area; Income of 5.883 households has been increased; People's awareness of forest protection has been improved. However, there are still some difficulties in process of implementing policy, such as low PFES money received by the forest owners; limited propaganda activities; insufficient activities of checking and monitoring quantity and quality of forests after payment. Therefore, the paper suggests that it is essential to support households to increase their income from forests; propaganda activities on the policy should be consecutively encouraged, and a mechanism to check and monitor forest areas and forest quality should be developed...

Van Duc, Gia lam, Hanoi is one of the first selected communes to pilot and pioneer in the application of the VietGAP standards in cabbage production. By the qualitative and quantitative information was collected by various tools, the study focused on analyzing the current status and behavioral differences between VietGAP and traditional farmers in pesticide use. The results showed that VietGAP farmers' behavior had positive changes compared to that of the traditional group leading to a significant decrease in the amount of pesticide in the crop but the level was not still really high as required. The main reason is that farmers' qualifications and knowledge are still limited, the inspection and supervision are not regular, theconsumer market is not stable. In order to promote and create motivation for farmers to strictly implement the regulations, it is necessary to enhance training, supervision, and the expansion of the market.