Published: 2024-04-25
Full Issue
Agronomy and Forestry Sciences
Morphological characteristics of Bracon hebetor (Hymenoptera: Braconidae), a larval parasitoid of coconut Black Headed Caterpillar Opisina arenosella Walker (Lepidoptera: Xyloryctidae)
Electronic version:
25 Apr 2024
| DOI:
10.52997/jad.2.03.2024
Abstract
|
PDF (431.5K)
Abstract
The Bracon hebetor is an essential natural enemy in suppressing the coconut black-headed caterpillar (BHC) Opisina arenosella, which was common in coconut field in Ben Tre province. Under laboratory conditions, with six-instar larvae of BHC as a host, the adult body of B. hebetor was yellow-brown and the male’s antennae were longer than those of the female, with oblong and rectangular shapes consisting of 17 - 20 segments, while the female’s antennae were square-shaped with 11 - 14 segments. The abdomen of B. hebetor was pale yellow, with its last segment being dark brown. Females of B. hebetor were larger than males. The average body length of female and male was 3.2 ± 0.17 mm and 3.0 ± 0.18 mm, respectively. The average body length of 2-day-old pupae was 3.0 ± 0.20 mm and that of 3-day-old ones was 3.5 ± 0.21 mm. The average egg length was 0.7 ± 0.07 mm. The findings of this study helped provide information on the identification of B. hebetor larval parasitic wasps on the BHC host, aiding in the search for natural enemies of BHC in coconut fields. Additionally, the research also facilitated the exploration of the biological and ecological aspects of this natural adversary in Vietnam.
Evaluation of specific combining ability and heterosis of 6 melon (Cucumis melo L. var. inodorus) self-pollinated lines at the 5th generation
Electronic version:
25 Apr 2024
| DOI:
10.52997/jad.2.02.2024
Abstract
|
PDF (313.1K)
Abstract
The study was carried out from August 2022 to February 2023 at the Biotechnology Center of Ho Chi Minh City with the objective of determining inbred melon lines with high combining ability and heterosis. The experiment was executed in plastic house condition and laid out in a completely randomized design with single factor with 3 replications, including 16 treatments corresponding to 15 hybrid combinations from 6 melon self-pollinated lines at the 5th generation (S5) and Kim Hong Ngoc variety as control. The results indicated that the melon line DLE06 used as female showed a high positive specific combining ability (SCA) for both fruit weight and the Brix of fruit with the DLE04 line used as male (THL14). Two hybrid combinations with high heterosis for fruit weight and the Brix of fruit flesh, including THL11 (1416.7 g; 16.33%) and THL14 (1520.0 g; 16.57%). Briefly, THL14 shows good growth and development potential in plastic houses, with morphological characteristics meeting the consumers’ preferences, and has potential to be developed into a new variey for production.
Effect of eggshell powder and phosphorus on growth and yield of MD7 groundnut variety in spring season in Phu Xuyen, Ha Noi
Electronic version:
25 Apr 2024
| DOI:
10.52997/jad.2.01.2024
Abstract
|
PDF (143.8K)
Abstract
The experiment was conducted to evaluate the effect of eggshell powder and phosphorus on growth and yield of MD7 groundnut variety in the spring season in Phu Xuyen, Ha Noi. The twofactor experiment was laid out in a split-plot design with three replications. The main plot consisted of three rates of eggshell powder (0, 300, 500 kg/ha). The sub-plot included three rates of phosphorus (30, 60, 90 kg/ha). The results showed that the growth and yield of plants fertilized with eggshell powder were higher than those with unfertilized eggshell powder. In addition, the growth traits and yield of MD7 groundnut variety increased with increasing phosphorus fertilizer doses from 30 kg P2O5/ha to 90 kg P2O5/ha under the same fertilized or unfertilized eggshell powder conditions. Briefly, the results indicated that the rate of 500 kg eggshell powder/ha combined with 90 kg P2O5/ha was suitable for MD7 groundnut variety to grow, develop and produce the highest yield in the spring season in Phu Xuyen, Ha Noi.
Animal Sciences, Veterinary Medicine, Aquaculture and Fisheries
The effect of water hardness on the development of embryo and larvae of silver carp (Hypophthalmychthis molitrix)
Electronic version:
25 Apr 2024
| DOI:
10.52997/jad.2.05.2024
Abstract
|
PDF (122.6K)
Abstract
This study aimed to investigate the effect of water hardness on the fertilization rate, hatching rate, survival rate, and deformity rate of common carp larvae. In the experiment, fertilized eggs of silver carp were incubated in different water hardness levels of 70, 100, 130, 160, & 190 mg CaCO3/L, with a stocking density of 400 eggs/L. The experimental results showed that the fertilization rate was high (78.0 - 79.3%) and did not show significant differences between the treatments (P > 0.05). The hatching rate ranged from 41.0 to 54.0% and larvae stage had the highest survival rate of 54.0% at 70 mg CaCO3/L. The deformity rate of larvae ranged from 5.7 to 74.3% with the lowest observed at the 70 mg CaCO3/L. From the results of the study, it can be assumed that silver carp eggs should be incubated in an aquatic environment with a water hardness of 70 mg CaCO3/L.
Application of conjunctival graft surgery in the treatment of corneal ulcers in dogs
Electronic version:
25 Apr 2024
| DOI:
10.52997/jad.2.06.2024
Abstract
|
PDF (771.7K)
Abstract
The study of conjunctival graft surgery for treating corneal ulcers in dogs was conducted at Alpha Pet Veterinary Clinic and Bang Pham Veterinary Hospital from August 2021 to August 2022. Dogs were clinically examined with corneal ulcers and corneal perforations, corneal reflexes, and then fluorescein 2% reagent was used to examine and measure the diameter of the corneal damaged area by using Castroviejo calipers. The surgical method of conjunctival stem grafting was applied and evaluated effects of treatment on corneal ulcers in dogs. A total of 3,024 dogs were examined and treated during the study period. There were 195 dogs with eye diseases, accounting for 6.45% of the cases. The rate of corneal ulcers was 15.90% (31/195 cases). Among the corneal ulcer cases, conjunctival graft surgery was performed in 14 cases. The successful rate of conjunctival stem grafting was 71.43%. The complication rate of conjunctival stem grafting was 42.86%, in which 2 cases of mild complications were successfully treated. The average wound healing duration was 39.45 days. The occurrence of complications depended on the types of complication. Mild complications including suture detachment and corneal edema appeared after 2.5 to 5.5 days while corneal epithelial cysts and ocular edema occurred at 22 to 42 days after surgery. Therefore, this method could be used in treatment of corneal ulcers, particularly in cases of deep ulcers or corneal perforations that required to directly connect to blood vessels.
Antibacterial activity of the black soldier fly (Hermetia illucens) larva protein hydrolysates against some pathogenic bacterial strains on freshwater fish
Electronic version:
25 Apr 2024
| DOI:
10.52997/jad.2.04.2024
Abstract
|
PDF (275.1K)
Abstract
The study was carried out to determine the antibacterial activity of protein hydrolysates from black soldier fly (Hermetia illucens) larva (PHBSF) on some pathogenic bacteria including E. ictaluri, A. hydrophila, A. verroni, and S. agalactiae on freshwater fish. The results showed that the tested bacteria were highly sensitive with significant difference (P < 0.05) in diameter clear zone compared to the negative control at the tested concentrations of 20, 35, and 70 mg/100 µL. Particularlly, E. ictaluri was sensitive at all three test concentrations with the diameter of clear zones following 14.0 ± 1.0, 18.7 ± 0.7, and 20.7 ± 0.7 mm, respectively. A. veronii and S. agalactiae were sensitive at concentrations of 35 and 70 mg/100 µL, and A. hydrophila with a clear zone diameter of 14.3 ± 0.3 mm at the concentration of 70 mg/100 µL. The PHBSF was able to kill A. veronii and S. agalactiae with MIC (minimum inhibitory concentration) = MBC (minimum bactericidal concentration) = 44 mg/mL, while E. ictaluri and A. hydrophila were inhibited at MIC 44 mg/mL, and MBC was 88 mg/mL. These results indicated that PHBSF could be potentially used to prevent fish diseases caused by E. ictaluri, A. hydrophila, A. verroni, and S. agalactiae.