Weight Loss and Germination Failure Caused by Psocids in Different Wheat Varieties

We investigated weight loss caused by Liposcelis entomophila (Enderlein) feeding in damaged (cracked) and intact kernels of 'Jagger' variety of hard red winter wheat over a 90-d period at 30 +/- 1 degrees C and 75 +/- 5% relative humidity. L. entomophila caused 8.5% weight loss in damaged wheat kernels, which was significantly greater than the weight loss found in intact wheat kernels (0.2%). We also evaluated the suitability of six wheat varieties commonly grown in Oklahoma, namely, Jagger, 'Endurance,' 'Overley,' 'Jagalene,' 'OK Bullet,' and 'Deliver' to support populations of four psocid species, namely, Liposcelis bostrychophila Badonnel, L. decolor (Pearman), L. entomophila, and L. paeta Pearman over a 30-d period. The greatest population increase was observed in L. bostrychophila followed by L. paeta. Subsequently, weight loss of damaged and intact wheat kernels and germination of intact kernels infested by L. paeta over a 45-d period were assessed in OK Bullet variety. L. paeta caused weight loss of 3.3% in damaged kernels, which was significantly greater than the weight loss found in intact kernels (0.4%). Based on our data, 40% of infested intact kernels failed to germinate after 45 d of infestation by L. paeta, but this decreased to 32% when adjusted using germination failure of uninfested kernels. Our data show that psocid infestations do not only cause considerable loss in weight of wheat, but also result in significant germination failure. These data call for the formulation of effective integrated psocid management strategies for stored wheat to mitigate the negative impacts of psocid pests.