Investigations Into Timing And Frequency Of Insecticide Applications For Cotton Fleahopper

The cotton fleahopper, Pseudatomoscelis seriatus (Reuter), is considered a key pest in the eastern part of Texas.  Both adults and nymphs feed on new growth, including small squares.  Squares up to pinhead size are susceptible to damage and the plant is most susceptible during the first three weeks of fruiting.  Cotton fleahopper numbers increase in wild hosts and move into cotton fields prior to squaring.  In the Southern Blacklands, the population dynamics are consistent through years and vary only in numbers.  Since cotton fleahoppers migrate continuously between wild hosts, cotton in this production region averages two insecticide applications for cotton fleahoppers, with a range of one to four applications depending on the populations.

 This study was initiated to evaluate cotton fleahopper control strategies in two different production regions in Texas in light of new research.  The study was expanded to include not only insecticide treatments but to incorporate movement and population studies of cotton fleahoppers.  Cotton fleahopper populations prior to squaring were high in the eastern part of the state (Brazos and Burleson Counties) but extremely low in the western part of the state (Lubbock and Tom Green Counties).  Populations were so low in wild hosts that it is difficult to determine how populations build up in levels in cotton. 

 Insecticide treatments again showed no significant yield advantages.  However, the trial in Williamson County indicated that yields in the insecticide treatments were numerically higher than the untreated.  After three years, it appears that thresholds in the Southern Blacklands are adequate.  Over the four years of the trial, the three automatic treatments have received 12 applications while the threshold treatments have received only five.  Producers may be able to more effectively target their applications.  The Southern Rolling Plains data indicate that thresholds may need to be re-evaluated.