PMV®-01 is the result of 10 years of scientific research in Belgium, the Netherlands and Spain. This research showed that the best protection against PepMV was achieved with a vaccination strategy based on a unique, mild and stable Chilean PepMV-isolate. This isolate quickly colonizes the plants and subsequently offers optimal protection against PepMV damage. Based on this knowledge PMV®-01 was developed. The product itself has a certified production process with strict quality controls.
But PMV®-01 is more than just a product, it is a strategy. Taking pre- and post-vaccination leaf samples is part of the vaccination strategy. Pre-vaccination samples are taken to check the young plants for a possible PepMV infection before vaccination and post-vaccination samples are taken to confirm a successful installation of the vaccine.
PMV®-01 is authorized for use as a biological plant protection product in the majority of the European member states and in a handful of countries outside the European Union. This number will be increasing in the near future. Currently, several evaluations procedures are in progress, both in- and outside Europe.
Since its very first use, a total surface of more than 10000 ha has been treated with PMV-01.
The most typical symptom of a PepMV infection is marbling of the tomato fruit. Brown sepals, bright yellow spots on the leaves and nettle-heads are also characteristic PepMV symptoms. In addition to these typical symptoms, some damage profiles with a physiological cause, such as flamed fruits or open fruits, can also be enhanced by the presence of PepMV.
Because PepMV is a RNA-virus, the replication process in the plant cell proceeds in a less controlled way and mutations occur regularly. The yellowing mutant and the necrotic mutant for example are two atypical forms caused by a mutation in the viral genetic material. Both mutants can cause severe damage to the crop.
Marbling of the tomato fruit
Brown sepals
nettle-heads
yellowing mutant
necrotic mutant
bright yellow spots
Four different strains of the virus are known: the Chilean strain (CH2), the European strain (EU), the Peruvian strain (LP) and the American strain (US1). Within these strains, many different individuals, called isolates, can be observed. In Europe, the Chilean strain (CH2) is dominant and present in 90% of the infections. If more strains are found in case of infection, the infection is usually more aggressive than when only one single strain is present. Within the strains, however, there is also variability among different isolates belonging to the same strain. Although different isolates within one and the same strain are genetically very similar, they can show very different levels of aggressiveness in the plant and, as a consequence, in the severity of the symptoms and the damage they cause. For example, there are very aggressive Chilean isolates, but also very mild ones that cause less symptoms.
In the early 2000s, PepMV became such a huge problem in Belgium and the Netherlands, that there was an urgent demand for support and control measures from the tomato sector. As a first step, fundamental research was carried out to identify the problem and a very strict hygiene protocol was developed to avoid PepMV infections. These strict hygiene measures turned out to be insufficient to ensure the grower a PepMV-free crop. Soon, research was oriented towards concrete, biological management tools and step by step PMV®-01 vaccination strategy was developed to immunize plants in order to prevent infection.
The next step of the vaccination strategy consists of a pre-vaccination sampling. The samples are taken no earlier than 1 week before planting. Depending on the grower’s preference, they can be taken at the plant nursery or at the grower’s place. The leaf samples are sent to the laboratory of Scientia Terrae VZW for molecular analysis in order to check if the plants are free of PepMV. The result of this analysis can be expected within 3 working days after arrival at the laboratory. Tomato plants are grown with great care and are usually free of PepMV. As soon as this is confirmed by the sampling and the accompanying analysis, the vaccination procedure can be started.
For optimum results, it is recommended to vaccinate as soon as possible after planting. The vaccination itself consists of one treatment with 4 to 8 L of PMV®-01/ha diluted in 150 to 300L water at a spraying pressure of 5 to 7 bar. In order to guarantee optimum effectiveness, the temperature of the product should never exceed 15°C during treatment. After vaccination, a crop treatment is recommended so that the vaccine can easily and quickly penetrate the plant. 4L/ha is considered to be the standard dose for an optimum effect and a sufficiently rapid colonization. In case of a high risk of contamination and the need for accelerated colonization, the dose may be increased to 8 L/ha.
The vaccine finally installs itself in the plants. After an incubation period of 4 to 6 weeks, the crop is protected against damage caused by PepMV for the entire growing season. During this period, the team of experts will take post-vaccination samples to confirm the successful installation of the vaccine.
The PMV®-01 vaccination strategy is based on the principle of cross-protection, a well-known mechanism in plant virology. At a first infection with the Pepino Mosaic Virus, the plant’s immune system is activated. Afterwards when the plant gets into contact again with the same virus , the plant’s immune system recognizes the virus and goes into action. As a result, the virus that causes the infection pressure will be eliminated by the plant itself.
The higher the level of genetic similarity between the virus causing the first infection and the virus causing the infection pressure afterwards, the more efficiently the mechanism will work. The active substance of PMV®-01 contains a mild isolate of the Chilean PepMV strain. This mild and stable Chilean isolate quickly installs itself in all the parts of the plant, so that the immune system will be activated in the entire crop 4 to 6 weeks after vaccination. After this period the plant is protected against future attacks of aggressive PepMV-isolates. Moreover, the mild isolate causes no symptoms on the fruits and has no effect on production, nor on quality.
PepMV damage on tomatoes
No PepMV symptoms after vaccination
The main reason why tomato growers use PMV®-01 is that PMV®-01 has proven to be an excellent solution for PepMV problems. Quality and production losses due to PepMV can be avoided after vaccination with PMV®-01. Strict quality controls during the production process guarantee the excellent effect of PMV®-01 and the accurate support of our vaccination experts ensures a correct implementation of the vaccination strategy.
PMV®-01 is currently authorized for use as a biological pesticide against PepMV in 22 different countries.
The effectiveness has been shown in a series of official GEP trials. In these trials, crops with and without PMV®-01 vaccination were inoculated with an aggressive PepMV isolate three weeks after the vaccination date. The PMV®-01 vaccinated crops showed no loss of quality and production, whereas the non-vaccinated crops showed average production losses ranging from 7 to 11%.
PMV®-01 vaccinated and non-vaccinated crops were inoculated with an aggressive PepMV isolate 3 weeks after the vaccination date. The PMV®-01 vaccinated crops showed no loss of quality and production in all GEP trials performed. In these 4 GEP trials, the non-vaccinated crops showed average production losses ranging from 7 to 11%. GEP: Good Experimental Practice.
In addition to the official trials, the production data of several commercial growers have been compared. The grower in the following example continually obtains higher yields of specialty tomatoes after PMV®-01 vaccination. Before vaccination, the crop suffered from a spontaneous, aggressive PepMV infection. After PMV®-01 vaccination, the plants were much healthier and more vigorous and their improved vitality resulted in a higher yield.
Commercial data from a tomato grower who continually obtains higher yields of specialty tomatoes after PMV®-01 vaccination. Before he used the vaccine, the crop suffered from a spontaneous, aggressive PepMV infection. After PMV®-01 vaccination, the plants showed a faster and more generative growth, resulting in more yield.
Production increase in specialties with PMV®-01 (kg/m2)
Vaccine against PepMV authorized in North America
PMV-01 is now available in Canada and the USA. PMV-01 is the first plant vaccine against Pepino Mosaic Virus (PepMV) in tomato authorized by EPA and PMRA. The product is registered in name of DCM and marketed by Biobest.
Source: http://www.hortidaily.com, 15/3/2019
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