Integration of Predator Releases with Insecticidal Soap Sprays for Management of the Sugarcane Aphid

The sugarcane aphid (SCA), Melanaphis sacchari (Zehntner) (Hemiptera: Aphiddae) is a new pest of sorghum in Kentucky. When left unmanaged SCA can lead to a complete crop loss. While multiple management tactics have been developed for grain sorghum, there are only two recommendations for sweet sorghum: a conventional insecticide and planting sweet sorghum earlier in the season. In this proposal we develop a third option that can be integrated with current prescribed practices: mass release of predacious green lacewings (GLW) to suppress SCA population growth early in the season. GLW release is a feasible tactic for both conventional and organic growers as it would be utilized prior to the need for insecticides. Testing will be done on eight Amish farms in Hestand KY in 2019 and 2020, averaging 1.5 acres per field. The Amish growers in Hestand use insecticidal soap to manage SCA currently. Fields will be divided into two treatments: insecticidal soap sprays plus GLW release or insecticidal soap sprays only, yielding four replicates for both treatments. SCA populations will be monitored weekly starting in June and ending at harvest. Upon detection of SCA in release fields, GLW will be ordered and held in cages in growth chambers supplied with food for two days once they are received to ensure that they are past their preovipositional period. GLW will then be released in mass in release fields. . GLW eggs will be counted immediately before and five days after release. Two weeks after the initial release, if SCA populations continue to increase in release fields a second release of GLW adults will be done with eggs counted in the same manner. If SCA action thresholds are reached in either treatment, growers will use insecticidal soap sprays. Yield will be assessed by growers. The results of this project will be assessed by comparing SCA populations, GLW egg abundance and yield between treatments. Outreach materials will consist of fact sheets, videos and presentations based on research results discussing SCA identification and scouting and methods for predator mass releases. Field days and workshops will be held to give these presentations.