Prevalence, incidence and molecular characterization of Phomopsis vexans (Diaporthe vexans) causing leaf blight and fruit rot disease of brinjal in Karnataka (India)

Abstract

The distribution, prevalence and incidence of Phomopsis vexans in six major brinjal growing agro-climatic zones of southwest India is reported. P. vexans was isolated from diseased leaf and fruit samples from six zones and was studied for its morpho-cultural and molecular characteristics. Eighteen isolates were tested for their pathogenicity on 30-days old brinjal seedlings. The ITS regions of these fungal isolates were used for the molecular identification followed by phylogenetic analysis. The incidence of leaf blight and fruit rot disease was high in northern transition zone (NTZ: 10.625.3% and 2133.3%) followed by southern dry zone (SDZ: 8.318% and 22.362%) and central dry zone (CDZ: 1017% and 2939%). All the isolates exhibited similarities in colony morphology. Variation was observed with regard to number of pycnidia, colony growth and type. Among the 24 isolates, 18 belonged to G-type and the rest could not be ascertained to either colony type. The 18 G-type isolates produced leaf blight and fruit rot symptoms 2528 and 4555 days post inoculation, respectively. In the phylogenetic analysis, all the 24 isolates formed a single clade, thus confirming their close genetic relatedness, though they were isolated from different agroclimatic zones of southwest India. Phylogenetic analysis of complete ITS2 sequence showed the presence of two distinct groups based on substitutions and indels observed among the populations where six isolates from NDZ and CDZ formed a distinct group from the rest of the isolates.

Management of Fruit Rot of Brinjal Caused by Phomopsis vexans

“…Disease free varieties namely, Pusa bhairabi and Pusa cluster were recommended for cultivation to avoid the Phomopsis blight and fruit rot (Singh et al, 2014). Further, hybrids observed to show less incidence of Phomopsis blight compared to farmer-collected seeds (Mahadevakumar et al, 2017).…”

“…The disease infection and spread are highly influenced by weather conditions. The incidence of Phomopsis blight was high during humid conditions (Mahadevakumar et al, 2017). The temperature of 25 0 C and pH 5.5 were optimum for the best growth of P. vexans on PDA culture media in 7 days at 12/12 D/N and; the spore formation was decreased by 30 0 C and reached to zero by 35 0 C (Islam et al, 2009).…”

“…Jayaramaiah et al, (2013) reported that Phomopsis vexans cause leaf blight to the extent of 5 to 23 per cent and fruit rot to the extent of 30 to 60 per cent. Recently Mahadevakumar et al, (2017) reported leaf blight incidence (8 to 25 %) and fruit rot incidence (15 to 62 %) caused by P. vexans. In another recent study, the Phomopsis blight incidence ranged from 8.81 to 23.85 per cent among 25 genotypes (Bhoshan and Samnotra, 2017).…”

Morphological and molecular characterization of Neopestalotiopsis vitis associated with leaf blight disease of Manilkara zapota —a new record from India

“…A total of 50 sapota trees were randomly selected from each field and the disease incidence was determined by counting the proportion of sapota plants affected by leaf blight disease and the incidence was calculated following the protocol of Mahadevakumar et al . (2017).…”

Caracterización morfológica de hongos asociados al agroecosistema café (Coffea arabica L.), en el estado de Tabasco, México

“…Las especies de hongos se identificaron teniendo como base a estructuras reproductivas (conidióforos, fiálides, conidios y clamidosporas), de las cuales se colectaron datos sobre descripciones morfológicas (forma, color y tamaño), descrita por autores mencionados; para Colletotrichum (Cristóbal-Martínez et al, 2017;James et al, 2014James et al, , 2014Nguyen et al, 2010;Prihastuti et al, 2009;Rojo-Báez et al, 2017;Singh & Doyle, 2017;Weir et al, 2012), para Fusarium (Nalim et al, 2011;Nguyen et al, 2010;Robles Yerena et al, 2016;Summerell et al, 2011;Weir et al, 2012) (Song et al, 2013); para Phomopsis (Gong et al, 2020;Mahadevakumar et al, 2017); para Hemileia (Carvalho et al, 2011). Para esto, los aislamientos se desarrollaron en caja petri conteniendo medio PDA durante 7 días y facilite describir dichas características macroscópicas.…”