Certification Programs Article 1

Grape and Apple Certification Programs: What are they and how do they work?

Authors: Victoria Hoyle and Marc Fuchs | Publishing Date: 2/8/2023

Viruses can be major threats to woody perennial crops such as grapevines and apple trees. They diminish the quality and quantity of the crops produced, causing substantial economic impacts. Once a plant is infected by a virus, there is no cure in a vineyard or an apple orchard. So how can we “nip it in the bud” before it becomes an issue? The best way to manage a virus in grapevines and apple trees is through prevention. In New York state, the Department of Agriculture and Markets (DAGM), Cornell University at Cornell AgriTech, and the New York grape and apple nurseries have teamed up to establish a certification program for implementing clean planting stock.

What is a Certification Program?

A certification program is a system of establishing clean planting stock absent of undesirable pathogenic agents through field isolation and a multitude of frequent testing and monitoring steps to set up a source of plant material that fits the desired criteria. Use of isolated and tested plants allow nurseries to produce clean planting stock that can be certified. Use of certified planting materials allow growers to minimize the risk of introducing infected plants into their field.

How does it work?

The establishment of the desired planting material is a multi-step process which can be broken down into three main production lines: National or Regional Institutions, nurseries, and growers. The establishment of clean planting stock occurs with the National Clean Plant Network (NCPN) and begins with the introduction of candidate materials, often sourced from imports or domestic accessions. These prospective vines are subjected to a series of disease testing panels, targeting select viruses, viroids, bacteria, and phytoplasmas. Grapevines or apples which test positive for undesired pathogens, go through pathogen elimination, often via microshoot tip therapy (grapes) or heat therapy combined with shoot tip grafting (apples). Following therapeutics work, plants that pass diagnostics make up the foundation block or G1 (first generation) material. This includes materials such as scion budwood, rootstock cuttings, liners, or seedlings. Usually only 2-4 plants of each accession are maintained at a G1 foundation site.

   Figure 1. Flow chart depicting the three areas of the production line for clean grapevines and what occurs at each stage shared by Marc Fuchs.

 

To help meet the demands for planting stock, materials from the foundation block are distributed to grape nurseries and will make up the G2 (second generation) population in what is known as an increase block. This process of maximizing the supply of pathogen-tested plants eventually continues through the G3 (third generation) and G4 (fourth generation) populations. Throughout this process, there is ongoing testing of G2 materials, and eventually G3 and G4 materials that fluctuates seasonally depending on the target pathogen to ensure its cleanliness in increase blocks (See article 2 for more information). These materials are then used to produce planting stocks by grafting (grapevine) or budding (apple) in a nursery block (Figure 1). Materials in nursery blocks are inspected for cleanliness as well. If materials in increase and nursery blocks match the criteria of cleanliness, the planting stocks will be certified in New York under Article 14 of the DAGM Law Prevention and Control of Disease in Trees and Plants, Regulations Part 150, Voluntary Program for the Production of Virus-Tested Plant Materials.

 

Apple and grapevine nursery blocks in New York. Photographed by Marc Fuchs.

How can you benefit from the program?

The development of foundation material is the cornerstone for sustainable grape and apple production. It is also the frontline for virus disease management. There are many advantages to seeking out certified planting stock with the largest being from an economic standpoint. Virus diseases of grapevines can cause damages ranging from approximately $900 (the low side impact of red blotch disease) to $92,000 (the high side impact of leafroll disease) over a 25-yr lifespan of a vineyard with cases of entire losses (the high side impact of tomato ringspot virus on own-rooted interspecific hybrid such as ‘Vidal’). Similarly, mixed infections of two or more latent viruses in apple trees have also been reported to result in a 10-30% reduction in fruit yield. For growers to reap the most benefit from a program such at this, vineyards and apple orchards should be established with certified stock from nurseries. For more information, on where to purchase pathogen-tested grapevine or apple materials in New York, proceed to article 2.

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