Other pests of maize are present in Africa which resemble to some degree the FAW. You can differentiate them by learning to identify the worms themselves at their different stages, and the type of damage they produce.
Below are different species of maize stalk borers and their life stages. The most important stem borers pests on maize are Busseola fusca, Chilo partellus and Sesamia calamistis. Busseola fusca is mostly present in the highlands, whereas Chilo partellus is widely present in the lowlands. Sesamia calamistis is present in both low and highlands.
C) Pupa (frequently inside the stem); D) Adult (not easily visible, flying over at night). Photos: Calatayud P.-A.
C) Pupa (frequently inside the stem); D) Adults: male top; female bottom (not easily visible, flying over at night). Photos: Calatayud P.-A. and icipe.
The main differences between stem borer infestation and FAW infestation are:
- the big holes left by the FAW. Generally, “big holes” as observed for FAW are not present in stemborers attacks (for both young and old larvae)
- the stem borer damage is characterized by a typical dead heart which is easy to see when the maize is young (Photo Series 2D)
- when stem borers larvae are getting old, they are less present in the whorl contrary to FAW; but they can be found in the maize stem, leaving holes in the stems with visible frass
A) Leaves with windowing and shot holes caused by early instars of FAW;
B) Extensive defoliation of leaves with fresh frass in the whorl, note the absence of dead heart; C) Defoliation by FAW larvae in the whorl.
Photos: K. Cressman, Subramanian Sevgan, icipe.
C): Hole left by the caterpillars when they are getting older and start boring the maize stem to feed inside the plant’s stems; D): Deadheart caused by the feeding activity of stem borer caterpillars into the
maize stems of young maize plants. Photos and source: Calatayud P.-A. & Agbodzavu, 2013.