Grapevine Red Blotch Disease (GRBD)
Vector(s) Live Map
GRBV Vector(s)
GRBD Symptoms
GRBD Resources
Typical red blotch leaf symptoms (V. vinifera cv. Pinot noir (PC: ML Cooper)
Grapevine red blotch virus (GRBV) is the causal agent of Red blotch disease (GRBD), an incurable grapevine disease that affects pH, sugar and phenolic accumulation (Blanco-Ulate et al. 2017; Girardello et al. 2019) & ultimately reduces wine quality.
From 2021-2024, the UCCE Napa Vit Team will be monitoring vectors in 9 unique vineyard blocks in Napa County across 6 AVAs. Our grower partners are monitoring 22 blocks across 11 AVAs, for a collective total of 31 blocks in 13 different AVAs.
Insect monitoring
S. Vengco
Spissistilus festinus
Threecornered Alfalfa Hopper (TCAH)
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K. Daane
B. Bahder
C. Kron
Scaphytopius sp.
Tortistilus albidosparsus
Comparing TCAH to Tortistilus
T. albidosparsus is generally larger than TCAH
C. Kron
C. Kron
Lateral ridge:
T. albidosparsus: meets above thorax
TCAH: meets further down the body
If you were T. albidosparsus, your lateral ridge would meet at your shoulder blade, whereas if you were TCAH your lateral ridge would meet at your mid to lower back.
Spissistilus festinus (TCAH)
Video: H. Fendell-Hummel
T. albidosparsus: "flat face" & lateral ridge closer to a 90° angle. TCAH: curved "face" & lateral ridge at an obtuse angle.
C. Kron
C. Kron
Spissistilus festinus (TCAH)
Video: S. Vengco
Additional Vector Resources
GRBD Foliar Symptoms
Reddening of the leaf blade in a blotchy pattern is a characteristic visual symptom of red blotch disease in black-fruited cultivars. White-fruited cultivars have less obvious visual symptoms.
These photo galleries showcase visual symptoms for red blotch disease or vines that are not infected with GRBV.
Visual symptoms of GRBD
Vines not infected with GRBV
Test your red blotch symptom knowledge with a short quiz!