Invasives Blog

Proper assessment of damage caused by FAW are essential for estimating socio-economic impact as well as allowing efficacy comparisons of novel plant protection products.
Image © S. Toepfer

A trans-regional group of researchers has sought to cast light on the numerous rating scales used for assessing leaf damage caused by the highly destructive invasive maize pest, the Fall armyworm (Spodoptera frugiperda). 

Native to the tropical and subtropical regions of the Americas, the devastating fall armyworm (FAW) causes major damage to maize as well as to other grassy crops, and has recently invaded much of Africa and large parts of southern and eastern Asia. Several thousand studies have now been conducted on this pest. Researchers and practitioners have however struggled to use consistent, practical and reliable methods to assess the pest`s damage. Such consistency is important when testing plant protection products or estimating the impact of the fall armyworm’s damage.

Researchers from the University of Neuchâtel, CABI in Switzerland and Rwanda Agriculture and Animal Resource Development Board (RAB) have now reviewed and tested all major leaf damage rating scales for the fall armyworm.  They provide an analysis of the advantages and disadvantages of different scales, streamline existing scales, and provide a new high-precision scale. They also clarify inconsistencies in the use of common scales, such as the Davis’ scale. This information has been made available via open source https://link.springer.com/article/10.1007/s10340-021-01359-2.

CABI’s Dr Stefan Toepfer and Patrick Fallet from the University of Neuchatel stated “it is hoped that our results help to standardise methods of assessing the damage of this serious maize pest among researchers, will reduce human bias, and will allow better comparability among studies”.

Researchers from RAB and University of Neuchatel of Switzerland students assess damage caused by FAW. Image © S. Toepfer

Additional information
PhD student joins the fight against devastating fall Armyworm pest

FAO and CABI Training of Trainers Manual
Community-Based Fall Armyworm (Spodoptera frugiperda) Monitoring, Early Warning and Management

CABI Fall armyworm Portal
Find out more about FAW through the CABI Fall armyworm Portal

CABI Action on Invasives
Discover more about CABI’s work to help Prevent, Detect and Control crop pests and diseases as part of its Action on Invasives programme

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