ABSTRACT

Hardlock is a major problem for cotton producers in the humid regions of the cotton belt. In Florida, from 20- 60% of the cotton is lost due to hardlock almost every year. When hardlock is only 20%, yields of 2 bale lint are often made. Yields are often reduced more by hardlock than any other factor including drought. However, this is seldom reported since identification and means of control have not been developed. The Cotton Disease Council has put the total yield loss from disease in the U.S. at about 12% per year for all diseases. Research with hardlock and boll rot have identified several different bacteria and fungi associated with symptoms and the incidence seems to increase with rainfall, humidity, high nitrogen, plant size and density. 2002 was one of the most severe years for hardlock in the humid areas of the cotton belt in recent history, and yields in Florida averaged 346 lbs/A. Hardlock has been known to be a problem for years with unknown etiology and without any apparent means of control. Symptoms do not appear until the boll opens and the locks of cotton look more like a slice of an orange than a fluffed out boll of fiber. In many cases the quality of the fiber is not severely affected, but yields have been noted to be reduced by 50% or more in the lower Mississippi River delta of Mississippi and Louisiana as well as other humid areas because conventional cotton pickers either knock the hardlocks to the ground or do a poor job of picking them. Due to the common occurrence of hardlock along the Gulf coast, there has been interest in strippers in UNR that could harvest cotton regardless of hardlock. However, gin deductions, higher seed costs, and poor stands in narrow rows especially with reduced tillage have led to less interest and the dilemma of how to harvest the cotton produced. Boll rot has been mentioned in the literature since the early 1900’s and has had many different organisms associated with it. However, no definite cause or control measure has been presented. Cotton was hand picked in the U.S. prior to 1950 and is now almost completely machine harvested. Most of the U.S. crop is harvested with spindle pickers which require that cotton be fluffed out to harvest it. New data from Florida has identified a cause of hardlock and a potential solution to the problem.