Bacterial spot incited by Xanthomonas cucurbitae: a serious emerging disease of cucurbits

North Central Region (NCR) of the United States of America (USA) is a leading region in pumpkin and squash production.
Illinois is the largest pumpkin producing state in USA. Bacterial spot, caused by Xanthomonas cucurbitae, is an emerging disease of cucurbits, especially on pumpkin and winter squash.
To assess the incidence of this bacterial disease in commercial pumpkin and winter squash fields in the NCR, field surveys were conducted within three weeks of harvest for two years.
In each field, 12 locations on an M-shape path were selected, and at each location, five fruits were randomly chosen and evaluated for the presence of bacterial spots.
During the survey, 119 pumpkin and 58 winter squash fields were visited.
Symptomatic pumpkin fruits were observed in 108 pumpkin fields with 28% infected fruits of all fruits examined.
Similarly, symptomatic fruits were observed in 52 winter squash fields, with 21% infected fruits.
The highest incidence of fruits with bacterial spot was 97 and 93% in pumpkin and winter squash fields, respectively.
Infected fruits had lesions measuring 1-3 mm in diameter.
Symptomatic fruits were collected from visited fields, and the causal agent was identified as Xanthomonas cucurbitae. The pathogen was identified based on the colony characteristics, polymerase chain reaction (PCR) test, and causal infection in pumpkin in a greenhouse.

IX South-Eastern Europe Symposium on Vegetables and Potatoes

M. Babadoost, Q. Liu

pumpkin, squash, cucurbits, bacterial disease, leaf infection, fruit infection

https://doi.org/10.17660/ActaHortic.2024.1391.59