Cultural, Morphological and Pathogenic Characterization of Alternaria porri Causing Purple Blotch of Onion

Twenty seven (27) isolates of Alternaria porri were isolated from diseased leaf samples collected from different onion growing regions of Bangladesh and characterized for cultural, morphological and pathogenic variabilities. A. porri colonies colony colour ranged between light to dark olivacious and grayish white with irregular, regular with concentric ring and regular without concentric ring shape. Margin of colonies were entire, irregular and wavy with effuse, fluffy and velvety texture. Isolates impregnated media with colour ranged between grey to brown on the reverse of the plates. Growth rate of isolates ranged between 2.433 and 3.950 mm/day with fast growth in isolate DSTR 02 and least in MMBH. Morphological variation in conidia production was between 7.720×103 to 47.02×103 per mm2 with sporulation time 3.33 to 11.00 days. The conidial shape was straight to curve with light to deep brown colour. The number of horizontal and vertical separation in the conidia ranged from 3.00 to 6.00 × 1.00 to 2.00 with size from 11.20 to 39.20 × 4.76 to 11.43 µm. In pathogenicity test isolates also exhibited variations in size of the lesions (2.77 to 7.55 mm) produced on onion leaves. The results demonstrate existence of considerable variation in cultural, morphological, and pathogenic characters of A. porri isolates prevalent in Bangladesh environment

Prevalence of seed-borne fungi of different vegetables seeds in Bangladesh

The experiment was carried out to evaluate the prevalence of seed-borne fungi of ten selected vegetables seeds e.g. amaranth, Indian spinach, bottle gourd, sweet gourd, snake gourd, okra, bitter gourd, cucumber, brinjal and country bean. Untreated and unknown grower’s bulk vegetables loose seeds were collected from three different seed sources of Rangpur district, Bangladesh e.g. New Bangla Seeds; Islam Seeds and Rafiq Traders. The high level of infection was found in the seeds of Rafiq Traders and the lowest infection was observed in the seeds of New Bangla Seeds. Islam Seeds provided moderate infection of fungal pathogens. Fungal fruiting bodies, mycelium (white and cottony) and acervuli were found under microscopic observation. The observed physical abnormalities viz. deformed, shrinkage, swelling, spotted and undersized seeds were recorded from all seed sources. Aspergillus flavus, Aspergillus niger, Fusarium sp., Alternaria sp., Chaetomium sp., Rhizopus sp. and unidentified bacteria were observed by blotter method. Aspergillus flavus showed maximum incidence (9.0%) in okra and minimum incidence (5.50%) in brinjal. Aspergillus niger was the most predominant (9.0%) in sweet gourd and minor (5.0%) in bottle gourd. Incidence of Fusarium sp. (5.0%) and Rhizopus sp. (8.75%) were predominant in bottle gourd. The lowest incidence for Fusarium sp. (2.50%) and Rhizopus sp. (3.0%) were found in snake gourd and amaranth respectively. The highest incidence of Alternaria sp. (4.75%) and Chaetomium sp. (9.0%) were found both in sweet gourd and bitter gourd but minimum incidence of Alternaria sp. (2.0%) and Chaetomium (3.75%) were recorded in amaranth and okra respectively. In case of unidentified bacteria, maximum incidence (4.50%) was recorded in bottle gourd

Experimental sites under survey at Jhikargacha Upazila in Jashore District of Bangladesh.

Experimental sites under survey at Jhikargacha Upazila in Jashore District of Bangladesh.</p

Farmers’ perspective on plant protection, fertilization, and growth regulators.

Farmers’ perspective on plant protection, fertilization, and growth regulators.</p

Farmers’ opinion on the occurrence, source, controlling of tuberose diseases.

Farmers’ opinion on the occurrence, source, controlling of tuberose diseases.</p

The socio-demographic profile of the participants in the present survey.

The socio-demographic profile of the participants in the present survey.</p

Overview of tuberose cultivation and cost-profit analysis in Jashore.

Overview of tuberose cultivation and cost-profit analysis in Jashore.</p

Cultural, Morphological and Pathogenic Characterization of Alternaria porri Causing Purple Blotch of Onion

Twenty seven (27) isolates of Alternaria porri were isolated from diseased leaf samples collected from different onion growing regions of Bangladesh and characterized for cultural, morphological and pathogenic variabilities. A. porri colonies colony colour ranged between light to dark olivacious and grayish white with irregular, regular with concentric ring and regular without concentric ring shape. Margin of colonies were entire, irregular and wavy with effuse, fluffy and velvety texture. Isolates impregnated media with colour ranged between grey to brown on the reverse of the plates. Growth rate of isolates ranged between 2.433 and 3.950 mm/day with fast growth in isolate DSTR 02 and least in MMBH. Morphological variation in conidia production was between 7.720×103 to 47.02×103 per mm2 with sporulation time 3.33 to 11.00 days. The conidial shape was straight to curve with light to deep brown colour. The number of horizontal and vertical separation in the conidia ranged from 3.00 to 6.00 × 1.00 to 2.00 with size from 11.20 to 39.20 × 4.76 to 11.43 µm. In pathogenicity test isolates also exhibited variations in size of the lesions (2.77 to 7.55 mm) produced on onion leaves. The results demonstrate existence of considerable variation in cultural, morphological, and pathogenic characters of A. porri isolates prevalent in Bangladesh environment

<i>Colletotrichum truncatum</i> Causing Anthracnose of Tomato (<i>Solanum lycopersicum</i> L.) in Malaysia

Tomato (Solanum lycopersicum L.) is a popular nutritious vegetable crop grown in Malaysia and other parts of the world. However, fungal diseases such as anthracnose pose significant threats to tomato production by reducing the fruit quality and food value of tomato, resulting in lower market prices of the crop globally. In the present study, the etiology of tomato anthracnose was investigated in commercial tomato farms in Sabah, Malaysia. A total of 22 fungal isolates were obtained from anthracnosed tomato fruits and identified as Colletotrichum species, using morphological characteristics. The phylogenetic relationships of multiple gene sequence alignments such as internal transcribed spacer (ITS), β-tubulin (tub2), glyceraldehyde 3-phosphate dehydrogenase (gapdh), actin (act), and calmodulin (cal), were adopted to accurately identify the Colletotrichum species as C. truncatum. The results of pathogenicity tests revealed that all C. truncatum isolates caused anthracnose disease symptoms on inoculated tomato fruits. To our knowledge, the present study is the first report of tomato anthracnose caused by C. truncatum in Malaysia. The findings of this study will be helpful in disease monitoring, and the development of strategies for effective control of anthracnose on tomato fruits