Spinach crown mite (SCM) can cause considerable damage to the leaves of spinach plants, reducing marketability and yield. This Vegetables NZ-ALT project aimed to understand what biocontrol options are available to be explored in further commercial-scale trials for SCM control.

The two biocontrol agents (BCAs) Neoseiulus cucumeris and Stratiolaelaps scimitus were tested in a laboratory to understand if they can feed and reproduce on SCM and how much they can predate each day.   

The second stage of the project was testing the efficacy of the BCAs under greenhouse conditions. Both research activities were undertaken by Bioeconomy Science Institute – Maiangi Taiao, in Auckland. 

The results showed combining the two commercially available BCAs delivered dual-zone effective pest control. When combined, they provided better control than used alone, even if single BCA use delivered significant SCM control under trial conditions. 

The findings have been summarised in a fact sheet along with an explanation of how the predator mites work, and practical recommendations for growers to follow when using predatory mites for pest control. 

The approach and learnings from this project may also be of interest to ALT crops where other pest mite species are difficult to control. 

Read more about the project: 

• September 2025: Two predator mites being trialled to control spinach pest.
• Download the factsheet on biological control of spinach crown mite.