Ian Todd, technical area sales manager for Scotland and Northern England, believes some ornamental growers still need to change their mindsets when it comes to nursery hygiene.

With a dwindling range of chemical crop protection products at growers’ disposal, due to the continuing loss of chemical actives, good nursery hygiene has become a high priority.  With few silver bullets left in the crop protection armoury, the industry need to change its way of thinking regarding how it’s going to tackle problems encountered during the growing season.

With this in mind, it is difficult not to over stress the importance of starting with a crop clean – by this I mean carrying out a thorough clean-up programme between crops.  I believe ornamental growers could learn a lesson or two from those producing protected salads.  Almost totally reliant on non-chemical means of crop protection, tomato, cucumber and pepper growers have become experts in carrying out thorough clean-up programmes between crops.

A few key pointers are:

• When bringing in new plant material, inspect it closely and if necessary reject suspect batches. It’s a good idea to quarantine new plant arrivals – by this I mean allow any latent disease to develop before unknowingly allowing it to infect the nursery.
• Where practical, isolate individual crops and different stages of production from one another.
• Whether growing in outdoor container beds, or in glasshouses, polytunnels or propagation units, all should all be cleaned between crops. Where appropriate, capillary matting and ground cover should be replaced between crops.   
• If growing under protection, don’t overlook maintenance issues as drips and leaks are often where disease outbreaks start.
• It’s also important to control weeds as these can become hosts not only for pests and diseases but also their vectors. 

To add to the challenges, with plastic prices continuing to rise, pot and tray recycling has become standard. While making sense from a sustainability angle as well as an economic one, it adds another level of complexity.  To help prevent the carryover of pathogens between crops it is essential these plastic items are thoroughly washed, ideally using hot water, and sterilised using a powerful disinfectant such peroxyacetic acid.  Check the label, but some can be used to disinfect all surfaces; including glasshouses, tools, pots, trays, benches, paths, building stores and irrigation systems.

Don’t overlook irrigation systems and water tanks. These should be regularly inspected, the water laboratory tested and where appropriate sanitised.  Where feasible, water tanks should be covered as otherwise they can all to often turn into major breeding grounds for water borne diseases, such as Pythium and Phytophthora.

Of course, prevention is better than cure.  With this in mind you can help ensure plants have instant protection from these diseases by incorporating the biofungicide Prestop into your growing media.  In the distant past biopesticides were regarded by some as ‘muck and magic’.  So for some this again requires a change of mindset.  Following years of extensive research and development and commercial trials, biopesticides have evolved into an area that growers ignore at their peril.  Biopesticides can make a major contribution helping to prevent diseases that in no time can lead to plant losses and lost revenue.