Association of phytopathogenic Pantoea dispersa inner boll rot of cotton (Gossypium hirsutum L.) in Maharashtra state, India Dipak T. Nagrale & Shailesh P. Gawande & Nandini Gokte-Narkhedkar & Vijay N. Waghmare Accepted: 2 July 2020 # Koninklijke Nederlandse Planteziektenkundige Vereniging 2020 Abstract During 2018–19, unusually higher inci- dences of inner cotton boll rot were reported in farmers’ fields from cotton growing tracts of Maharashtra. Ex- tensive survey was conducted to investigate these in- stances of boll rot. An unusual emerging problem in cotton has been associated with reduced boll develop- ment and yield. Green bolls with and without any sign of damage were collected from farmers fields and dis- sected under aseptic conditions. Bacterial species belonging to members of Enterobacteriaceae family (facultative anaerobe) were predominately isolated from rot affected cotton bolls. Four bacterial strains isolated from four locations were identified on the basis of morphological, biochemical and molecular characteri- zation. Pathogenicity of all the four isolates (CBR2- YTML, CBR1-JLGN, CBR2-BLDN and CBR5-JLGN) was proved by Koch’s postulates. To the best of our knowledge, this is the first report of occurrence and association of phytopathogenic bacteria Pantoea dispersa, a member of the Enterobacteriaceae family as a potential and principal pathogenic agent causing inner cotton (G. hirsutum L.) boll rots in Maharashtra state, India. Keywords Cotton . Inner boll rot . Facultative anaerobe bacterium . Insect vector . Mechanical injury Introduction Cotton (Gossypium hirsutum L.) is the most important fiber and oilseed crop cultivated in the India, China, United States, Australia, Egypt, and African tropics (Fortucci 2002). India has the largest area under cotton cultivation (12.429 million ha) and largest cotton pro- ducer in the world (CICR, Annual Report 2017–18). Maharashtra is one of the major cotton growing state in India with acreage of 4.207 million ha and estimated production of 8.5 million bales (170 kg each) and pro- ductivity of 343.48 kg lint/ha (CICR, Annual Report 2017–18). Though, insects are major biotic factors Eur J Plant Pathol https://doi.org/10.1007/s10658-020-02071-0 Dipak T. Nagrale and Shailesh P. Gawande contributed equally to this work. D. T. Nagrale (*) : S. P. Gawande Scientist (Plant Pathology), Division of Crop Protection, ICAR- Central Institute for Cotton Research, Post Bag No.2, Shankar Nagar P.O., Nagpur 440010, India e-mail: dip29unique@gmail.com e-mail: Dipak.Nagrale@icar.gov.in S. P. Gawande e-mail: spgawande1@gmail.com N. Gokte-Narkhedkar Principal Scientist (Nematology) & Head (I/c), Division of Crop Protection, ICAR- Central Institute for Cotton Research, Post Bag No.2, Shankar Nagar P.O., Nagpur 440010, India e-mail: nnarkhedkar@rediffmail.com V. N. Waghmare Principal Scientist (Genetics), Director (Acting) & Head, Division of Crop Improvement, ICAR- Central Institute for Cotton Research, Post Bag No.2, Shankar Nagar P.O., Nagpur 440010, India e-mail: vijayvnw@yahoo.com