In addition, hurricanes in 1999 damaged the portion of the crop that could have been affected and may have masked some problems. The problems in 1998 ranged from fields with very little abortion to isolated fields where essentially all the fruit on the lower four to six fruiting nodes aborted, especially first position fruit. Both plant bugs and drought stress can cause poor fruit retention. However, large scars were noted at the aborted fruiting sites, indicating the problem was not due to plant bugs. Plant bugs cause abortion of pinhead squares, which leaves small scars.
Large scars indicate boll rather than square abortion.
In fields where the problem was detected early, small and abnormally shaped bolls could be found on the ground. Drought stress can cause abortion of small bolls on heavily fruited cotton. However, abortion of small bolls was observed in some fields that had just begun blooming and were not under moisture stress. Roundup-induced fruit abortion is a result of poor pollination, although the exact cause of the poor pollination is unknown. Such bolls had low seed counts in many locks.