Tomato brown rugose fruit virus – ToBRFV – has become one of the most disruptive threats facing greenhouse tomato and pepper growers worldwide. First identified in Israel in 2014, the virus has since spread across Europe, North America, and Asia. In Canada, ToBRFV was first detected in 2019 in an Ontario tomato greenhouse, with subsequent confirmations in Alberta, Quebec, and additional Ontario facilities through 2024. Recent genomic surveillance of Canadian greenhouses has revealed multiple independent introductions, with the virus detected in roughly one in five surveyed facilities.
The stakes are high: ToBRFV overcomes all three known tobamovirus resistance genes in commercial tomato cultivars, including the widely relied-upon Tm-22 gene. Infected fruit develop brown or yellow rugose patches that render them unmarketable, and once the virus enters a greenhouse, complete eradication without crop destruction is extremely difficult. The virus spreads through contaminated tools, hands, clothing, growing media, seeds, and even pollinating bumblebees.
Early detection is the single most important tool growers have against ToBRFV. The sooner you identify an infection, the faster you can isolate affected plants, implement biosecurity protocols, and prevent facility-wide spread. Here is a practical breakdown of the three main testing approaches available to Canadian greenhouse operations today.
Three Testing Methods for ToBRFV Detection
1. ImmunoStrip Rapid Field Test
The Agdia ImmunoStrip for ToBRFV is a lateral flow device that uses monoclonal antibodies to detect viral protein directly from plant tissue. It works like a pregnancy test for plants: extract sap from a suspect leaf, dip the strip, and read the result in about 30 minutes – no lab, no equipment, no specialized training.
ImmunoStrips are ideal for routine scouting. Walk your greenhouse rows, test suspect plants on the spot, and get immediate answers. With an analytical sensitivity of 64-320 pg/mL, the ToBRFV-specific ImmunoStrip offers superior specificity compared to using a generic TMV strip, which cross-reacts with several related tobamoviruses and cannot distinguish ToBRFV from TMV or ToMV.
Best for: Field scouting, rapid screening of symptomatic plants, incoming transplant inspection, and situations where immediate on-site answers matter. The 25-strip pack is an efficient way to screen multiple areas of your greenhouse in a single session.
2. ELISA (Enzyme-Linked Immunosorbent Assay)
For operations that need to screen large numbers of samples – seed lots, transplant batches, or facility-wide surveys – ELISA provides high-throughput, cost-effective detection with the same monoclonal antibody specificity as the ImmunoStrip. Agdia’s PathoScreen Kit for ToBRFV processes 96 samples per plate in a laboratory setting.
ELISA is the go-to method for seed health testing programs, where you may need to screen thousands of seeds before planting. It requires a microplate reader and trained personnel, but the per-sample cost is significantly lower than testing each seed individually with rapid strips. Agdia also offers individual reagent sets and pre-coated plates for labs that build their own assays.
Best for: High-throughput seed screening, bulk transplant certification, and systematic greenhouse surveys where sample volumes justify lab-based testing.
3. AmplifyRP XRT (Isothermal Molecular Detection)
When you need PCR-level sensitivity without PCR infrastructure, Agdia’s AmplifyRP XRT for ToBRFV detects viral RNA at femtogram-level sensitivity (15 fg/µL) – roughly 4,000 to 20,000 times more sensitive than serological methods. It uses recombinase polymerase amplification (RPA), an isothermal process that runs at a single temperature and delivers results in about 30 minutes.
The XRT is especially valuable as a confirmatory tool. Samples that test positive by ELISA can be retested with XRT for molecular-level confirmation – using the same crude extract, no re-extraction needed. It is also the best choice for detecting low-level infections in asymptomatic plants, which recent Canadian research has shown can carry significant viral loads in emerging leaves and fruit tissue even before visible symptoms appear.
Best for: Confirming ELISA-positive results, detecting early or asymptomatic infections, testing environmental samples (irrigation water, nutrient solution), and any situation requiring molecular-level sensitivity. The 48-reaction kit is ideal for labs running routine molecular surveillance.
Which Test Should You Use? A Practical Decision Framework
The most effective ToBRFV testing programs combine multiple methods. Here is how leading Canadian greenhouse operations layer their approach:
Routine scouting (weekly): ImmunoStrips on any plant showing foliar mosaic, leaf narrowing, or fruit discoloration. This catches active, symptomatic infections quickly and cheaply.
Pre-planting seed screening: ELISA on bulk seed lots before transplanting. This is especially critical if sourcing seed from regions with known ToBRFV pressure.
Early-season baseline testing: AmplifyRP XRT on a representative sample of transplants 2-4 weeks after planting, before symptoms would typically appear. Recent research shows that sampling nutrient solution or monitoring bumblebee activity can detect ToBRFV up to two weeks before visual symptoms become apparent.
Confirmation of positives: Any ImmunoStrip or ELISA positive should be confirmed with XRT molecular testing to rule out cross-reactivity with TMV or ToMV.
Beyond Testing: What to Do If ToBRFV Is Detected
A positive test result requires immediate action. Isolate affected rows, restrict worker movement between zones, and implement full tool sanitation protocols – soap and water first, followed by disinfection with approved virucides. Report confirmed cases to your local CFIA office, as the agency actively monitors ToBRFV distribution across Canadian greenhouse facilities.
For facilities considering resistant varieties, note that while commercial cultivars with intermediate resistance (IR) are now available, no variety offers complete immunity. Resistant cultivars buy time but do not replace biosecurity – consistent testing remains essential even in IR crops, as resistance-breaking isolates have been documented.
Where to Source ToBRFV Test Kits in Canada
Immunomart is Canada’s authorized distributor of Agdia diagnostic products, offering the complete ToBRFV testing suite: ImmunoStrips, PathoScreen ELISA kits, AmplifyRP XRT kits, and supporting reagents including positive and negative controls. Browse the full range of Agdia ImmunoStrips and plant ELISA kits available for Canadian growers.
Disclaimer: Agdia diagnostic kits referenced in this article are intended for plant pathogen detection in agricultural, horticultural, and research settings. For regulatory guidance on plant health in Canada, consult the CFIA.
