Implementing Ultra Violet Light as Disease Control in Apple and Pear Nurseries and Newly Established Orchards

Fireblight Erwinia amylovora, has become an increasingly problematic apple disease. Over the past 10 years, the increased prevalence of bacterium, developing chemical resistance, and changing weather patterns has increased the destruction it causes within the region.  It spreads most quickly through young fast growing tissue and in young plantings of apples and pears. While a notable problem in orchards, it can be devastating in nursery settings. In our nursery alone the disease causes tens of thousands of dollars of damage annually despite our existing management system that includes, spraying, scouting, removal of infected material, and testing for chemical resistant strains. 

There are hundreds of nurseries in the northeast. These nurseries range in size from less than one thousand  to one million+ trees annually. Additionally, in young orchards, trees are small enough in the first three years that the UV machine will be useful. Fireblight is most devastating in the nursery and the first three years of an orchard's life. I have seen entire young orchards destroyed by blight. 

Streptomycin, Oxytetracycline, copper and  Apogee growth hormone are the primary chemical protectants for fireblight. Of these treatments, only copper is available to organic orchards. Ultraviolet light would be acceptable and is a very effective organic substitute. 

By adding ultraviolet light, a proven biocide to this bacteria, to our existing regiment we hope to better control the disease on our farm.  Dr. Cox has published a design to build and a protocol for applying ultraviolet light in a mature orchard setting.  We plan to work with him to redesign the device and adapt it for the nursery and young orchard setting.  

Our main goal is to better control the damage and spread of fireblight in our nursery, but the device will also help control for other diseases and pests including apple scab, powdery mildew, mites and aphids. 

The application of ultraviolet light will not entirely replace chemical applications but will supplement and decrease the reliance and frequency required.  Ultraviolet light offers several additional benefits: pests cannot build resistance to ultraviolet light in the ways they do to some chemicals, ultraviolet light is safer for the applicator to apply,  Ultraviolet light can not have any wider effect on the environment. Unlike chemicals, it can not enter the water table, it can’t get into the air. Once built, the UV-C light application rig is cheaper to operate than the annual cost of chemicals.