PJB-2024-413
PREVALENCE AND PATHOGENICITY OF XANTHOMONAS CUCURBITAE CAUSING BACTERIAL SPOT OF CUCURBITS AND EFFECT OF RESISTANCE INDUCERS ON DISEASE DEVELOPMENT
Priyanka Bhardwaj
Abstract
During the present studies, disease was prevalent in all cucurbit growing areas surveyed in sub-tropical zone of Himachal Pradesh, India. Disease severity ranged from 35.33 and 72.33 per cent during 2021 and 40.00 to 94.67 per cent during 2022. Symptoms were prevalent on all aerial plant parts in pumpkin, bottle gourd and sponge gourd. All the fourteen isolates from different locations were variable in terms of cultural and pathogenic characters. Colony diameter ranged from 12.22mm to 43.71mm while, colony colour varied from light yellow to yellow. Colonies were mucoid, circular with smooth margins and convex elevation. Biochemically, all the isolates tested positive for esculin hydrolysis and protein digestion test while, negative for Gram staining. All isolates were pathogenic on three cucurbit species under study viz., pumpkin, bottle gourd and sponge gourd being more virulent on their respective crop. Incubation period ranged from 1.67 days to 4.67 days in different isolates and disease severity ranged from 5.33 per cent to 35.33 per cent during cross pathogenicity tests. Among resistance inducers, mean minimum (10.56%, 10.82 and 11.48%) disease severity was recorded with salicylic acid leading to maximum (71.03, 62.57, 56.39%) disease control in pumpkin, bottle gourd and sponge gourd, respectively. Phenol content was recorded to be higher in all leaves sprayed with resistance inducers being mean maximum (42.17 mg/GAE/g) in salicylic acid. A negative and significant correlation was recorded between disease severity and phenol content which could influence disease severity of pumpkin, bottle gourd and sponge gourd up to 63.57, 69.50 and 95.46 per cent.During the present studies, disease was prevalent in all cucurbit growing areas surveyed in sub-tropical zone of Himachal Pradesh, India. Disease severity ranged from 35.33 and 72.33 per cent during 2021 and 40.00 to 94.67 per cent during 2022. Symptoms were prevalent on all aerial plant parts in pumpkin, bottle gourd and sponge gourd. All the fourteen isolates from different locations were variable in terms of cultural and pathogenic characters. Colony diameter ranged from 12.22mm to 43.71mm while, colony colour varied from light yellow to yellow. Colonies were mucoid, circular with smooth margins and convex elevation. Biochemically, all the isolates tested positive for esculin hydrolysis and protein digestion test while, negative for Gram staining. All isolates were pathogenic on three cucurbit species under study viz., pumpkin, bottle gourd and sponge gourd being more virulent on their respective crop. Incubation period ranged from 1.67 days to 4.67 days in different isolates and disease severity ranged from 5.33 per cent to 35.33 per cent during cross pathogenicity tests. Among resistance inducers, mean minimum (10.56%, 10.82 and 11.48%) disease severity was recorded with salicylic acid leading to maximum (71.03, 62.57, 56.39%) disease control in pumpkin, bottle gourd and sponge gourd, respectively. Phenol content was recorded to be higher in all leaves sprayed with resistance inducers being mean maximum (42.17 mg/GAE/g) in salicylic acid. A negative and significant correlation was recorded between disease severity and phenol content which could influence disease severity of pumpkin, bottle gourd and sponge gourd up to 63.57, 69.50 and 95.46 per cent.
To Cite this article:
Under Review
We Welcome Latest Research Articles In Field Of Botany The Pakistan Journal of Botany is an international journal .... Read More
