–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Swathing seems to have interrupted the potato leafhopper increases that were seen prior to cutting. All the fields sampled prior to swathing in north central Kansas exceeded the treatment thresholds. Conversely, all the fields sampled post-swathing had potato leafhopper population well below economic injury levels, i.e. 20 potato leafhoppers per 20 sweeps pre-swathing vs. two per 20 sweeps post-swathing. Continued monitoring would be prudent as these pests may stray around until October and continue to produce offspring.
Spotted alfalfa aphids are still present in alfalfa fields but at relatively insignificant infestation levels. These aphids seem to do very well in mid-summer’s hot, dry conditions but usually don’t reach densities heavy enough to cause yield-reducing stress.