5.15 CBCVd-Monitoring 2021

Sponsor: Bayerische Landesanstalt für Landwirtschaft, Institut für Pflanzenbau und Pflanzenzüchtung (Bavarian State Research Center for Agriculture, Institute for Plant Production and Plant Breeding) Financing: Bayerisches Staatsministerium für Ernährung, Landwirtschaft und Forsten (StMELF) (The Bavarian State Ministry for Food, Agriculture and Forestry) Erzeugergemeinschaft HVG (Hop Producers Group) Project Management: S. Euringer Team: IPZ 5b, IPZ 5a, IPS 2c Duration: April 1, 2021 to March 31, 2021 Sampling Period: June 2021 to September 2021

CBCVd monitoring was once again on the agenda in the Hallertau in the 2021 crop year. No monitoring was carried out in other German growing areas. The selection of plots for sampling was guided by their assumed risk of infection. Unlike in the previous year, 10 individual plants were always combined into a single mixed sample for a reduced number of sample units but an increased number of plants sampled.

Table 5.5: Classification of CBCVd monitoring in 2021

Classification of CBCVd monitoring in 2021

Cultivation area monitoring in infested regions

Plot section Samples Sampled plants Farms

165 1650 16500

HVG Biogas monitoring 137 137 1370 Voluntary Monitoring (EG HVG) ~15 ~15 150 Areas of the newly infested farms (2021) ~30 ~45 450 Sum ~350 ~1850 18470 187

Table 5.6: Results of CBCVd monitoring in 2021

Year

Affected farms Infested hop area [ha]

2019 2020 2021

3 7 10 37 94 91

During monitoring in 2021, CBCVd was detected for the first time in 3 additional farms, which increased the total number of affected farms to 10. These farms are located on the periphery of areas that are already known to be infested. The overall area on which CBCVd was detected in 2021 decreased because plots on which CBCVd was detected in the previous year were cleared.

The following findings were the result of CBCVd monitoring in 2021. They confirmed data from the 2020 CBCVd monitoring:

• Infested areas are expanding • The level of infestation in affected farms ranges from low to high. A future increase in the level of infestation ought to be expected • There is a need to organize coordinated consultations for infested farms during their control efforts and containment measures • Within a farm, the spread can progress very quickly without a mitigation concept • There is great uncertainty on farms that tested negative but are located in areas containing infested farms • There are indications that CBCVd infections have existed in the Hallertau growing region for several years • Heterogeneous crops (in terms of soil, cultivation, and variety) make visual assessments more difficult – verification in the laboratory is a necessity • The severity of symptoms is not the same every year and there may be time lags between infection and the appearance of symptoms

Outlook 2022

• Monitoring will continue in 2022 • EU regulations governing so-called “Plant Passports” (that is, safety clearance certificates) will be revised to include stipulations relating to sanitary standards for viroid pathogens The Hüll Hop Research Center (LfL IPZ) is supported financially and in terms of staffing by StMELF, LfL IPS, GfH e.V. and the HVG e.G. Other research activities and any official appraisal activities are only marginally influenced by such support.