Spissistilus festinus (Hemiptera: Membracidae)susceptibility to six generalist predators

Authors: Kron, Cindy; Sisterson, Mark

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2020
Publication Date: 11/30/2020
Citation: Kron, C.R., Sisterson, M.S. 2020. Spissistilus festinus susceptibility to six generalist predators used in augmentative biological control. American Journal of Enology and Viticulture. 15(1). Article 0242775. https://doi.org/10.1371/journal.pone.0242775.
DOI: https://doi.org/10.1371/journal.pone.0242775

Interpretive Summary: Grapevine red blotch virus is an economically important pathogen of wine grapes. Recent studies documented that the threecornered alfalfa hopper is capable of transmitting grapevine red blotch virus. Release of commercially available insect predators may aid in reducing abundance of threecornered alfalfa hoppers in vineyards, which in turn, may reduce spread of Grapevine red blotch virus. In this study, five species of commercially available insect predators were evaluated to determine which (if any) threecorned alfalfa hopper life stages were within the host range of the predator. Two species of predator did not consume any threecornered alfalfa hoppers (Cryptolaemus montrouzieri and Sympherobius barberi). Two species consumed only early instar three cornered alfalfa hoppers (Zelus renardii and Hippodamia convergens). Finally, once species (Chrysoperla rufilabris) consumed all five immature stages of the threecorned alfalfa hopper. Results indicate that Chrysoperla rufilabris is an ideal candidate for additional field testing to determine if augmentative release of C. rufilabris can reduce threecornered alfalfa hopper populations in vineyards.

Technical Abstract: Spissistilus festinus (Say) (Hemiptera: Membracidae) has been reported to transmit Grapevine red blotch virus (GRBV). Grapevines infected with GRBV exhibit reduced sugar accumulation, altered secondary metabolite production and delayed berry maturation that negatively impacts wine quality and economics. Augmentative biocontrol may be a useful integrated pest management (IPM) tool for suppressing S. festinus populations in vineyards, but minimal research has been conducted on testing potential predators against the different life stages of S. festinus. The susceptibility of S. festinus adults and nymphs (1st through 5th instar) to predation by six commercially available biocontrol agents in petri dish and bell bean plant arenas was determined under greenhouse conditions. No significant mortality of S. festinus nymphs or adults occurred when exposed to Cryptolaemus montrouzieri adults, C. montrouzieri larvae and Sympherobius barberi adults in petri dish or bell bean plant arenas. Significant mortality of 1st and 2nd instar nymphs of S. festinus in the presence of Zelus renardii nymphs was observed in petri dish arenas, but not in bell bean arenas. Hippodamia convergens adults and Chrysoperla rufilabris larvae both consumed a significant number of S. festinus nymphs in petri dish and bell bean arenas. No significant predation of S. festinus adults was documented in this experiment. Results of this study aid in identifying predators that may be suitable candidates for additional field testing to determine their potential efficacy as biocontrol agents of S. festinus in a vineyard setting.