Serenade® Optimum – Getting the best in Apples & Pears for Fire blight

When it comes to controlling Fire blight, Serenade Optimum is one of the great options available to New Zealand Apple and Pear growers for control of this potentially destructive disease.

However, as a biological product, the mode of action of Serenade Optimum is often not fully understood. Having a full understanding of how Serenade works and how to use it effectively is important to get the very best return on investment.

What is Serenade Optimum?

Serenade is an optimized fermentation product of a unique microbial strain: the QST 713 strain of Bacillus subtilis. And while there are other strains of Bacillus subtilis, there is a tremendous difference between these strains. QST 713 is unique and different from other Bacillus in the types and amounts of biological chemistry that it can produce.

What’s contained in Serenade?

Production expertise is very important when producing biological products. All Serenade products are manufactured using a highly optimized and well controlled fermentation process that results in a consistent product. Each batch of Serenade contains not only a standardized viable spore count of the QST 713 strain of Bacillus subtilis but also standardized levels of biological chemistry. Serenade is also very stable and does not require refrigeration.

How does Serenade work?

On Fire blight, Serenade has two modes of action.

• Direct Contact:
  • Due to antibacterial biological chemistry produced in the fermentation process, Serenade provides preventative control of Erwinia amylovora via direct contact:
  • Difficidin group: inhibition of cell division, protein and cell wall synthesis
  • Macrolactin group: Blocks protein synthesis and cell division
    
    
• Antagonistic colonization.
  • The viable spore count contained in Serenade provides flower colonization of Apple and Pear flowers:
  • QST 713 is able to grow and colonize the flower blossom and exclude growth of Erwinia and provide niche exclusion of bacteria.
  • In situ antibacterial biological chemistry production
  • Peak colonization occurs 24hrs after application

When should I apply Serenade?

With these modes of action, it is recommended that Serenade Optimum is used as a protectant application, applied during lower pressure levels of Fire blight and during periods of early or later bloom, i.e. lower numbers of flowers.

From early flowering apply Serenade and repeat at three to five day intervals as a programmed application to maintain colonization of flowers. Peak colonization occurs 24hrs after application. This can be tank mixed with a fungicide spray if required.

Streptomycin with its systemic activity remains the main strike weapon against heavy infection potential during periods of large flower numbers. If forecast infection risk becomes high or extreme, apply Streptomycin according to label directions.

For late flowering if forecast conditions are for an extreme event, apply Streptomycin as a first application as per label directions and follow up with Serenade Optimum three to five days later, depending on disease risk.

In post flower situations, Serenade Optimum will also protect newly grown shoots from Fire blight. Apply at 7 day intervals to protect from Fire blight infection to damaged foliage.

Is Serenade compatible with other crop protection products?

Serenade is extremely robust and can be used in a tank mixed with most commonly used Fungicides and insecticides. This includes Streptomycin. There is no need to apply it separately. This makes it an extremely versatile option for disease control.