The sugarcane aphid arrived to KY a month earlier in 2016 than in 2015

Raul Villanueva, University of Kentucky Extension Entomologist

Insect description and damage
The invasive sugarcane aphid (SCA) Melanaphis sacchari has arrived to Kentucky almost a month ahead in 2016 compared to 2015 (https://kentuckypestnews.wordpress.com/2016/02/16/sugarcane-aphid-losses-with-sweet-sorghum/). Sugarcane aphids have caused yield losses going from 30% to

Figure 1.  An adult SCA (pink arrow) and first 
instar nymphs (blue arrow) detected on a sweet 
sorghum  field in Trigg County, KY on 07/15/16. 

(Photo credit Raul T. Villanueva)

100% to sorghum grower since 2013 on many states of the US. Sugarcane aphids affected severely grain and sweet sorghum fields last year in GA, SC, MO, and TN and KY. Last Friday (7/15/16), a small numbers of sugarcane aphids were detected in a field of sweet sorghum in Trigg County (Fig. 1). Although the numbers are still low in this field, populations may pick up sooner. So far in the U.S all SCA populations are composed by female individuals. Each female can produce 6 to 12 nymphs per day, and in less than one week they can complete its life cycle. This rapid life cycle can cause quick outbreak of SCA populations.

Sugarcane Aphid Collected in Kentucky

Doug Johnson, Extension Entomologist, University of Kentucky

Sugarcane aphid (SCA) has been collected in two western Kentucky (KY) Counties. County Extension Agents Ben Rudy in Fulton Co. and Trent Murdock in Graves Co. have collected SCA from grain and sweet sorghum respectively. Identity was confirmed by Dr. Lee Townsend, Extension Entomologist, with the University of Kentucky (UK) in Lexington. Thus far, only the two infestations have been reported. The infestation in Fulton Co. is below treatment threshold, but the infestation in Graves Co. is much larger. Regardless of size, this does confirm that this new sorghum pest which likely migrates in from the Deep South can reach Kentucky during, if late, in the production season. Sugarcane aphid is a threat to all forms of sorghum (grain, forage, sweet) and will infest many other grasses including Johnson grass, which can act as a host for reproduction and a source of infestation.