Live microbial products: keeping the declared count all the way to the field

For a chemical pesticide, the declared content measured at release is a reliable guide to what reaches the field. For a live product, the number that matters is the count of viable cells or spores when the farmer applies it, and that number depends on everything that happens between the factory and the field. This article explains how Huasheng handles that difference.

1. Why live products are handled differently

The FAO and WHO manual for chemical pesticides expects formulations, in contrast to biological pesticides, to remain satisfactory for at least two years from release when stored as the label directs [2]. Its companion manual for microbial pesticides notes that microorganisms are sensitive to elevated temperatures, that the accelerated storage test used for chemicals is not suitable for them, and that their labels therefore need an expiry date and storage conditions [1].

2. What the specification fixes

For a live product, the specification Huasheng agrees with the customer states the strain identity, the method used to count viable cells, when the count is made, and the storage conditions that apply. A count without its method and its timing cannot be compared with another supplier's figure, or with a later test of the same goods.

3. Storage conditions differ by product

The table shows the storage conditions and shelf life declared for a selection of Huasheng live products. Some need refrigeration, some tolerate ambient storage, and the Orvan™ formats also set a time limit once a pack is opened.

4. Transport and warehousing

General guidance for crop protection products applies with more force to live ones. FAO notes that shelf life is shortened when products are stored at high temperature, and that stock planning must allow for the time products spend in transit [3]. CropLife guidance asks that products be stored under a roof and out of strong sunlight, which also damages plastic containers and labels [4]. For products that must be refrigerated, the storage condition is part of the order and is planned with the shipment.

5. On arrival and before use

• Check the production date or batch release date and the shelf life on the label, and plan stock so that the oldest goods are used first.
• Move refrigerated products into cold storage on receipt and keep the others within their declared range, away from direct sun.
• Keep packs closed until use; for products with an opening limit, such as Orvan™, use the opened pack within the stated days.
• Follow the label on compatibility: some live products are not mixed with fungicides or other inputs that harm them.