Cultural practices affect sap beetle (Coleoptera: Nitidulidae) populations in matted row and plasticulture production of strawberries

Abstract

Strawberry sap beetles, Stelidota geminata (Say), are a pest problem in strawberry production in the northeast United States. Both adults and larvae reduce the quality and yield as the result of feeding directly on ripe, overripe, and decaying berries. This study (i) examined the seasonal activity and feeding injury of sap beetle populations in the matted row and plasticulture production systems, (ii) compared the yield and fruit quality associated with the sap beetle feeding in both production systems, and (iii) evaluated the effects of mulching and the timing of renovation in the matted row system on sap beetle populations. Results provide clear evidence that certain cultural management practices of each production system can significantly reduce the risk of sap beetle injury. The lack of straw mulch in the matted strawberry rows resulted in minor reductions in damaged fruit and sap beetle emergence; however, this is not a common practice in commercial production. The heavy mulch treatment provided no additional protection for sap beetles or any decrease in fruit damage compared to the normal mulched strawberries. The timing of renovation immediately after the last harvest resulted in 60% fewer adults emerging compared to the emergence in plots renovated 10 d later. This practice reduced the number of beetles that leave the strawberry field to infest other host crops, as well as lowering the risk to strawberries the following year. This study provides the first evidence that the annual plasticulture system can significantly reduce the risk of sap beetle feeding injury. Strawberries grown in this system are at less risk to sap beetles because of the physical restrictions of the plastic mulch, along with earlier ripening and less accessibility of berries hanging higher on plants above the mulch layer.