Vineyard Leafhoppers
Leafhopper Identification
Management Strategies
Local Leafhopper Research
2022 Leafhopper Counts
There are three species of leafhoppers (Erythroneura) in Napa County vineyards; Western grape, Virginia creeper, and Variegated leafhopper. Adults and nymphs damage vines by feeding in the leaf mesophyll, giving leaves a white speckled appearance.
Leafhopper Identification
Western Grape Leafhopper
The Western grape (E. elegantulais) leafhopper is native to California. The adults are a creamy-white color with orange markings and two distinct black dots on their head. The nymphs are whitish yellow with six yellow spots on their back.
H.Wilson
H.Wilson
UC IPM
Viginia Creeper Leafhopper
The Virginia creeper (E. ziczac) leafhopper is invasive to California. The adult is identified by brownish-yellow zigzag markings. First instar nymphs are pale-colored and difficult to distinguish from WGLH; 2nd-5th instar nymphs have four distinctive red spots on the thorax.
UC ANR
H.Wilson
M.Hobbs
M.Hobbs
Variegated Leafhopper
The variegated leafhopper (E. variabilis) is also an invasive species in California. Adults and nymphs are darker in color than the other vineyard leafhopper species. Adults are rust colored and the nymphs are yellowish orange with dark edges around their body.
UC IPM
H.Wilson
H.Wilson
Leafhoppers in Yellow Sticky Traps
Management Strategies
UC IPM
Biological Control
Parasitism by Anagrus spp. can be helpful in controlling populations of the Western grape leafhopper. Parasitism of the other species is low. These egg parasites have not adapted to Virginia creeper leafhopper as a host and the variegated leafhopper lays its eggs too deep in the leaf tissue for them to be reached.
Leaf Removal
Removing basal leaves when 1st generation nymphs start emerging can reduce adult leafhopper populations. This practice is most effective when done as soon as the first instars of the 1st generation are detected on leaves. (Lowery 2021)
Insecticides
Chemical controls used for WGLH can be effective against VCLH, but the timing of sprays must be adjusted to target the first brood of VCLH. VCLH is well controlled by one, properly timed application of a neonicotinoid insecticide or an insect growth regulator (IGR). Our studies indicate that in organic vineyards oil and pyrethrin are the most effective treatments. Oil applications are most effective against the younger nymphal stages (1st to 3rd instars) of the first brood, but two applications may be needed. Pyrethrin is most effective during peak emergence of first brood nymphs; this typically occurs when the later stage nymphs (4th instar) begin to appear. For both products, it is important to have good coverage. Since IGRs, oils and pyrethrin target nymphs, early season sprays are more effective because the first VCLH brood is relatively well synchronized (i.e. eggs, nymphs, and adults).
To learn more about these strategies see Lowery 2021, UC IPM Leafhopper, and "Recent Advances in Management of Virginia Creeper Leafhopper" for more information.
Local Leafhopper Research
From May to August of 2021, the UCCE-Napa Vit team monitored leafhopper populations at a site in St. Helena. Yellow panel traps were used to monitor adults. And 10 leaves were collected and inspected for nymphs. Data were recorded weekly.
To view a full summary of UCCE Napa leafhopper trials from 2021-2022, click here.
In spring 2021, we detected many leafhoppers in our traps, evidence of a large overwintering population.
In mid-May (bloom), we detected the first Virginia creeper nymphs of 2021.
Oil sprays targeted 1st and 2nd instar nymphs:
On May 12, 2021, the first treatment of 2% oil was applied (1.5 gpa oil in 75 gpa of water). On May 27 and June 9, 2021, the second and third treatments of 2% oil were applied (2 gpa in 100 gpa of water). One final oil treatment (1.25% or 1.25 gpa in 100 gpa of water) was made on June 22, 2021, although few nymphs were present at that time and application rate was lower.
The summer generation of adults was very small. During Aug & Sep, nymphs of the 2nd generation were rarely detected.
Click here to view 2022 adult and nymph leafhopper counts.