Parrot-Beaked Cotton Bolls

Several calls and pictures have came in this week regarding “parrot-beaked” cotton bolls.  There are a number of things that can result in parrot beaked bolls including insect damage, heat stress, and water stress as well as others.  The root cause of parrot beaked cotton bolls is incomplete fertilization of a given flower.  When this happens, the number of seeds per boll is reduced thus the boll does not completely develop and usually has a flat spot on one side (the side that the flower wasn’t properly fertilized on) and the tip hooks over.

When parrot-beaked bolls are present, there are usually similar locs per boll; however, there are not as many total seeds in the boll.  This is particularly true in 1-2 locs of the affected boll.  Historical data would suggest that there are substantial differences in varietal susceptibility to heat stress and subsequent appearance of parrot-beaked bolls.  In addition, the longer cotton is subjected to water stress the greater the incidence of parrot-beaked bolls.

If parrot-beaked bolls are present, there is little that can be done at this time.  If a higher number of affected bolls are present, reduced yield may occur as these bolls usually do not open properly making it difficult to harvest all seed cotton from affected bolls.  Also, given that there are reduced numbers of seeds in the affected bolls, boll weight and lint production is reduced which can contribute to reduced yields.  At this point, continue to manage your crop based using established thresholds and your experience.

Photo Courtesy of Jeff North.