Management of Ralstonia solanacearum (potato wilt disease) virulence by using bioactive compounds

Potato is an important vegetable crop of Bangladesh which is facing challenges worldwide due to a quarantine pathogen, Ralstonia solanacearum. It is a very successful bacterial pathogen against most of the traditional management practices. Suspension of ten bioactive compounds viz. propolis, honey, turmeric powder+oil, turmeric powder, magnesium chloride, boiled rice fluid, boiled rice fluid+iodine, sun dried cow dung powder, honey+iodine and sodium bicarbonate were evaluated and compared with control (sterile water), commercial bactericide (Krosin AG) and farmers practice (stable bleaching powder). In vitro assessment was done by comparing the inhibition zones produced on TZC (tetrazolium chloride) solid medium in disc diffusion method. All of those compounds produced larger inhibition zones as compared to control which indicated the effectiveness of the test compounds against the bacteria. To screen out the performances of those compounds in vivo, potato seedlings were inoculated in sterilized soil by soil soak method. Later, mature plants were inoculated in unsterilized soil to find the better resulting compound(s) in field soil condition against the disease. Finally, suspension of cow dung (@25%), propolis (@ 6mg/ml) and turmeric powder (@25%) were selected for trial as soil and seed treatment against the pathogen. It was found that, cow dung reduced 28.89% disease severity index which was followed by 26.67% in propolis and 22.22% in turmeric powder as compared to control (84.44%) in artificially inoculated potato plants against R. solanacearum.&#x0D; J. Biodivers. Conserv. Bioresour. Manag. 2020, 6(1): 65-76</jats:p

In-vitro Screening of some Chemicals and Biocontrol Agents against Erwinia carotovora subsp. carotovora, the Causal Agent of Soft Rot of Potato (Solanum tuberosum)

Erwinia carotovora subsp. carotovora was isolated from the infected potato tuber and was identified by pathological, morphological and biochemical studies. Five chemicals viz. Cupravit 50 WP (Copper oxychloride), Sulcox 50 WP (Copper oxychloride), Champion 77 WP (Copper hydroxide), Indofil M- 45 (Mancozeb) and Bavistin 50 WP (Carbendazim) and five biocontrol agents viz. Bacillus subtilis, Pseudomonas fluorescens, Rhizobium leguminosarum, Trichoderma harzianum and Aspergillus flavus were screened out in vitro against the growth of Erwinia carotovora subsp. carotovora by well diffusion method measuring the inhibition zone. Among the chemicals, Sulcox 50 WP (Copper oxychloride) was highly effective against it with 31.00 mm inhibition zone after 48 hours of incubation at 0.2% concentration when 100 ?l/well was used. In case of biocontrol agents, Bacillus subtilis was the best against the bacterium with 16.67 mm inhibition zone after 48 hours of incubation. DOI: http://dx.doi.org/10.3329/agric.v11i2.17480 The Agriculturists 2013; 11(2) 1-9</jats:p

Effect of age and height position on physical and mechanical properties of rubber wood (Hevea brasiliensis) of Bangladesh

The physical and mechanical properties of rubber (Hevea brasiliensis) wood of Bangladesh of 20, 25 and 30-year age groups were studied. The moisture content of rubber wood was 63% and volumetric shrinkage was 7.43%. The green density and air-dry (12% moisture content) density of rubber wood from 30 years age class was 570 and 590 l.c./m3. Significant difference in moisture content, shrinkage and density was found among the different age classes and height positions. However, longitudinal shrinkage did not vary among the age classes. The MOE and MOR values (air dried) of rubber wood from 30 years age class was 9200 and 65.33 MPa. In most conditions, significant difference with age class and height positions was observed for mechanical properties. The maximum values were found at the bottom position of 30 years age group. On the other hand, the lowest values were observed in the top position of 20 years age group. The strength properties were lower than teak (Tectona grandis), but some strength properties were higher than mahogany (Switenia macrophylla). DOI: http://dx.doi.org/10.3329/bjsir.v49i2.22000 Bangladesh J. Sci. Ind. Res. 49(2), 79-84, 2014</jats:p

Two new species of Xanthagaricus and some notes on Heinemannomyces from Asia

Xanthagaricus flavosquamosus and X. necopinatus, two new species of Agaricaceae, are described and illustrated from Asia. Macroscopically, both species are closely related to each other, but there are obvious micromorphological and molecular differences between them. Morphological and phylogenetic data showed that the two new species are distinct from other known species of the genus Xanthagaricus. Xanthagaricus flavosquamosus from China is characterized by its small, yellow basidiomata, short clavate cheilocystidia, epithelial pileipellis, and verrucose basidiospores measuring 5–5.5 × 3–3.5 μm. Xanthagaricus necopinatus from Bangladesh is characterized by having small, yellow basidiomata, a fugacious annulus, clavate to narrowly clavate cheilocystidia, epithelial pileipellis, and rugulose-rough basidiospores measuring 4–5 × 2.7–3.2 μm. In addition to the new species, a Heinemannomyces collection from China is reported. Morphological data and molecular phylogenetic analyses fully support the Chinese collection being Heinemannomyces splendidissimus, a species of Agaricaceae, originally described from Southeast Asia. Detailed descriptions, color photos and illustrations of the three species are presented. A key to the genus Xanthagaricus occurring in Bangladesh and China is provided