Streamlining leaf damage rating scales for the fall armyworm on maize

Abstract The fall armyworm ( Spodoptera frugiperda , Lepidoptera: Noctuidae), which is native to the Americas, has recently invaded Africa and Asia. There, it become a major pest of maize Zea mays ). variety methods used assess feeding damage caused by its caterpillars makes difficult compare studies. In this paper, we aim at determining leaf rating scales for are most consistently purposes, might provide possibilities statistical analyses, would be an acceptable compromise between detail workload. We first conducted literature review then validated common under field laboratory conditions. Common nominal “yes-no scale” that only assesses incidence, as well difficult-to-analyse ordinal combine incidence severity information such “Simple 1 5 whole plant scale”, “Davis’ 0 9 whorl & furl or “Williams’ scale”. These have been adapted many times, sometimes incorrectly, were wrongly cited. therefore propose simplifications some these novel “0.0 4.0 index” improves precision parametric data analyses. argue choice scale use should depend on desired level detail, type analyses envisioned, manageable time investment.