D3439: Increased resilience in sorghum aphid suppression as indicated by region-scale shifts in natural enemy diversity and abundance over a decade

Indicators of increasing suppression of sorghum aphid, Melanaphis sorghi (Hemiptera: Aphididae), have been observed since the aphid’s invasion into the large sorghum production system including the far-southern and south-central regions of the U.S. Great Plains. Indicators of suppression across a decade-long time period of sampling commercial sorghum fields were: aphid abundance trending downward over the years, overall natural enemy abundance trending upward, and natural enemy diversity shifting spatially and over the years (increasing abundance of selected parasitoids, primarily Aphelinus nigritus, in the far southern region and relatively more lady beetles, several species of Coccinellidae, in the south-central region). Classic predatory-prey population dynamics also became more frequent as the decade progressed. These data confirmed suppression potential as documented in cage exclosure experiments conducted in the same two regions.