Seasonal dynamics of Spissistilus festinus (Hemiptera: Membracidae) in a Californian vineyard

Authors: PRETO, CINDY - University Of California; BAHDER, BRIAN - University Of Florida; BICK, EMILY - University Of California; Sudarshana, Mysore; ZALOM, FRANK - University Of California

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2019
Publication Date: 2/23/2019
Citation: Preto, C.R., Bahder, B.W., Bick, E.N., Sudarshana, M.R., Zalom, F.G. 2019. Seasonal dynamics of Spissistilus festinus (Hemiptera: Membracidae) in a Californian vineyard. Journal of Economic Entomology. 112(3):1138-1144. https://doi.org/10.1093/jee/toz022.
DOI: https://doi.org/10.1093/jee/toz022

Interpretive Summary: The three-cornered alfalfa hopper, Spissistilus festinus (Say) (Hemiptera: Membracidae) was shown to vector Grapevine red blotch virus (GRBV) in a greenhouse study. GRBV is the causal agent of Grapevine Red Blotch Disease, which reduces the quality of wine produced from infected grapes. Due to the general lack of prior concern regarding S. festinus on grape vines, the biology of this species in vineyards has been largely unknown. A two-year study with weekly sampling was conducted in a Californian vineyard to increase knowledge of S. festinus seasonal dynamics and distribution. The overwintering S. festinus adults were first captured in the vineyard before bud break. Detection of late-instar S. festinus nymphs, the first in-field adult generation, and grape anthesis occurred concurrently in 2016 and 2017. Two in-field S. festinus generations were documented by peaks in sweep net sampling of vineyard groundcover in 2016, whereas only one generation was observed in 2017. There was an inverse relationship between the number of S. festinus adults sampled on ground cover and the number of girdles in the grapevine canopy. Spissistilus festinus exhibited an aggregated distribution in the vineyard and a significant edge effect. Results from this study will contribute to the development of sampling and management guidelines and determine timing of control measures to reduce populations of S. festinus within vineyards to minimize the virus spread.

Technical Abstract: The three-cornered alfalfa hopper, Spissistilus festinus (Say) (Hemiptera: Membracidae) was shown to vector Grapevine red blotch virus (GRBV) in a greenhouse study. GRBV is the causal agent of Grapevine Red Blotch Disease, which reduces the quality of wine produced from infected grapes. Due to the general lack of prior concern regarding S. festinus on grape vines, the biology of this species in vineyards has been largely unknown. A two-year study with weekly sampling was conducted in a Californian vineyard to increase knowledge of S. festinus seasonal dynamics and distribution. The overwintering S. festinus adults were first captured in the vineyard before bud break. Detection of late-instar S. festinus nymphs, the first in-field adult generation, and grape anthesis occurred concurrently in 2016 and 2017. Two in-field S. festinus generations were documented by peaks in sweep net sampling of vineyard groundcover in 2016, whereas only one generation was observed in 2017. There was an inverse relationship between the number of S. festinus adults sampled on ground cover and the number of girdles in the grapevine canopy. Spissistilus festinus exhibited an aggregated distribution in the vineyard and a significant edge effect. Results from this study will contribute to the development of sampling and management guidelines and determine timing of control measures to reduce populations of S. festinus within vineyards to minimize the virus spread.