Mango (Mangifera indica L.) is considered a desirable fruit in international markets and is grown throughout tropical and sub-tropical countries around the world (Alemu, 2014). Stem end rot is the ...

Sesame (Sesamum indicum L.) commonly known as ‘til’ is the most ancient and widely grown oilseed crop of Pakistan. During 2020, field survey conducted in various research fields of Faisalabad (31°2...

Brown leaf spot of rice is one of the most economically important diseases of rice, accounting for yield losses of 4 to 52% (Dhaliwal et al. 2018). A detailed survey of brown leaf spot was conducted in major rice-growing areas of Punjab, Pakistan during 2017-2018. Leaf spot symptoms were brown to purplish-brown, rounded spots, 0.7 to 1.0 cm in diameter, with grayish centers and chlorotic haloes. Disease occurrence was approximately 60% in the visited fields. Lesions were cut into 5 mm2 pieces, surface disinfested in 3% NaOCl for 2 min, rinsed three times with sterile distilled water, transferred to PDA plates, and incubated at 25oC for 1 week. Resulting colonies were powdery to hairy in texture and black in color after 4 to 5 days. Conidiophores were erect, unbranched, apically flexuose, septate, with flat conidial scars on the edges, up to 70 µm long. Conidia were thick walled, smooth and brown with (3-) 5 (-7) distosepta, cylindrical to cigar-shaped, 17-36 × 5-9 µm (Ellis 1971). For molecular identifica...

Production of watermelon (Citrullus lanatus) in Malaysia was 150,000 mt in 2020 (Malaysian Department of Agriculture, 2021). In November 2019, nine locally produced watermelon fruit (red flesh, seedless) from five local stores in the states of Kelantan, Terengganu, and Penang exhibited sunken, circular, brown lesions that enlarged to1.5 to 10 cm in diameter with scattered orange masses of conidia. Lesions coalesced to cover approximately 50% of the fruit surface. Lesions were surface sterilized by spraying 70% alcohol onto the fruit followed by drying with sterilized paper towels. A total of 153 tissue segments (1×1 cm) were excised from the rind, immersed in 1% sodium hypochlorite for 3 min, rinsed twice for 1 min in sterilized distilled water, air-dried, transferred to potato dextrose agar (PDA) plates, and incubated at 25±1°C for 7 days. Single-spore transfers produced pure cultures, resulting in 12 isolates. Colonies on PDA were initially white and turned pale gray with age. Conidia were hyaline, one end round and the other narrowly acute, aseptate, smooth-walled, straight, cylindrical to clavate, 10.5-16.5 µm × 3-4.5 μm (n = 30). Observed morphological characters matched published description of Colletotrichum spp. (Damm et al. 2012). Internal transcribed spacer (ITS) and glyceraldehyde-phosphate dehydrogenase (GAPDH) genes were amplified using primer sets ITS1/ITS4 and GDF1/GDF2, respectively. All sequences were deposited in GenBank (MW856808 for ITS; MZ219296 for GAPDH). A BLASTn search of both sequences on GenBank showed 99% identity with C. scovillei along with other closely related Colletotrichum species. Phylogenetic analysis of ITS and GAPDH alignments, using maximum likelihood along with reference strains of closely related species from Mycobank, confirmed species identity as C. scovillei. A pathogenicity test was conducted on two healthy watermelon fruit (red flesh, seedless). A 6-mm-diameter mycelial plug of a colony on PDA was positioned on a 0.5-cm-long wound on each fruit; a sterile PDA plug placed on a similar wound on the opposite side served as a control. Fruit were incubated at 25±1°C for 7 days in plastic-wrapped trays above distilled water to maintain high humidity. Small, sunken, circular brown lesions appeared and expanded at inoculation sites within 7 days. Symptoms were identical to those produced by natural infections, and the controls were asymptomatic. Isolates from the lesions at the inoculation sites were confirmed as C. scovillei based on morphological characteristics, fulfilling Koch's postulates. The pathogenicity test was conducted four times with a total of eight fruit. Many species in the C. orbiculare complex cause watermelon anthracnose (Keinath, 2018). To our knowledge, this is the first report of C. scovillei (C. acutatum species complex; Damm et al. 2012) causing anthracnose on watermelon in Malaysia. Anthracnose caused by C. scovillei has been confirmed on other crops such as pepper (Toporek and Keinath, 2021), banana (Zhou et al., 2017), and chili (Oo et al., 2017). This insight will inform efforts to improve management of watermelon anthracnose in Malaysia.

Soft Rot Pectobacteriaceae including Pectobacterium and Dickeya species are responsible for causing potato blackleg in the field and tuber soft rots in storage conditions reducing the yield and quality of the tubers (Adeolu et al. 2016). Since several decades, D. dianthicola has been reported as a plant pathogenic bacterium in USA, Australia, many European countries and in Morocco as well (Oulghazi et al. 2016). In January 2017, potato plants exhibiting blackleg symptoms were observed in local potato fields in the Okara district of Punjab, Pakistan. Initially, the stem bases of infected plants blackened and then rotted with vascular discoloration. Bacteria were isolated from the symptomatic part of the stem showing blackleg symptoms on the nutrient agar medium followed by streaking of the isolates on the specific crystal violet pectate (CVP) medium (Hélias et al. 2012). After 3 days on CVP at 28°C, pectinolytic bacteria showed the formation of pits around the bacterial colonies. To identify the pectinolyt...