|Medrano, Enrique - Gino|
|Schuster, Greta - Texas A&M University|
|Fields, Kendall - Texas A&M University|
Submitted to: Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2016
Publication Date: 10/27/2016
Citation: Medrano, E.G., Schuster, G., Fields, K. 2016. Cotton (Gossypium hirsutum L.) boll rot and associated microorganisms from fields in south Texas. Agricultural Sciences. 7:732-746.
Interpretive Summary: Cotton is a significant cash crop of US Agriculture, particularly in Texas. In south Texas, a recent cotton yield decrease has been partially attributed an increased incidence of boll rot. Although there have been general associations as to the cause of the infections, research toward dissecting the situation is lacking. This study was initiated to focus on the potential causes of the malady. During 2011 and 2012, boll samples were collected from a variety field trial on a research farm located at Texas A&M University-Kingsville, and from several producer fields. The variety trial consisted of five current cultivars of cotton to compare both overall disease occurrence and relative susceptibility to boll rot. The commercial fields were located from Wharton County down to US border counties (Cameron and Willacy). Findings from this work included identification of cotton varieties that are apparently less susceptible to boll rot than the others tested. The producer field boll disease survey revealed that a particular bacterial type from the group Bacillus is associated with the disease. This research provides crucial baseline information to begin formulating avoidance and/or control strategies to address boll rot in cotton grown in south Texas, thereby assisting producers in maximizing yield.
Technical Abstract: Increased cotton production losses in areas of south Texas have been generally associated with a rise in boll rot that reduces lint quality and causes deteriorated seed. Here, we measured boll rot incidence during two growing seasons (2011 and 2012) at a south Texas variety trial in research plots and in producer fields. The variety trial was planted at a research farm (Kleberg County) and boll rot susceptibility was compared between five current cultivars. The commercial fields surveyed were located in the Coastal Bend (Wharton and Nueces Counties) and Rio Grande Valley regions (Cameron and Willacy Counties). Bolls with evidence of damage potentially inflicted by piercing-sucking insect vectors were dissected for disease detection and plated for microorganism characterization. Purified colonies were putatively identified based on a Fatty Acid Methyl Ester profile analysis. In the variety trial, the highest incidence of disease occurred in July for both growing seasons, and significant differences in susceptibility to boll rot between cultivars were determined (P > 0.05). The highest boll disease incidence was 28% in August 2012 for the Coastal Bend region and also 28% but in June 2011 in the Rio Grande Valley. Bacillus species were predominately associated with boll rot of south Texas cotton from all the fields studied over the 2 year period. This is the first report to directly study the occurrence of boll rot in south Texas and associate a potential and prevalent causative agent.