Title : Molecular diversity and spatial distribution of the corn planthopper (Stenocranus pacificus) in the Philippines
Abstract:
Corn planthoppers (Stenocranus pacificus) are sap-feeding insect pests of maize and other grass species which can cause significant chlorosis, sooty mold infection, and stunted crop growth. Here, we generated abundance, molecular diversity, and spatial distribution data for S. pacificus in three localities, Los Baños and Bay, Laguna, and Malaybalay, Bukidnon in order to support plant biosecurity efforts. Across the sampling sites, the nymph stage exhibited the highest mean count (171.67 ± 49.37 SE), followed by the adult stage (117.33 ± 36.82 SE), while the egg stage had the lowest mean (40.33 ± 4.38 SE). Both wing morphs (brachypters and macropters) were also observed, indicating potential for local colonization and dispersal. Molecular detection using the cytochrome c oxidase 1 gene confirmed species identity, clearly delineating collected samples from Peregrinus maidis and Stenocranus pseudopacificus, and showing 99–100% sequence similarity to S. pacificus populations from Indonesia. Phylogenetic analysis and haplotype network analysis further revealed that Philippine populations cluster closely with Indonesian sequences, but are distinct from Japanese Stenocranus species, suggesting a recent introduction or shared ancestry with Indonesian populations and low intraspecific divergence among Philippine localities. A distribution map reflecting 28 local occurrences of S. pacificus was also generated. Taken together, these findings provide the first integrated dataset on S. pacificus in the Philippines, which can be used to strengthen plant biosecurity surveillance, guide pest management strategies, and provide baseline data for monitoring potential invasions and genetic shifts of this pest.
