The Fate of Sugarcane Shoot Borer Scirpophaga excerptalis Natural Infestation on Sugarcane Varieties: The Role of Predatory Ants

Abstract

In Indonesian sugarcane plantations, the infestation severity by the sugarcane shoot borer, Scirpophaga excerptalis, depends on the sugarcane variety and the presence of natural enemies. However, evaluating the resistance of sugarcane cultivars to borer infestations typically involves artificial infestations and laboratory assays that do not take into account the role of natural enemies, especially predatory ants, as a significant factor in the borer larvae's mortality. The predatory ants associated with sugarcane plants could prey on the shoot borer neonate larvae before the larvae reach the growth point of the sugarcane and cause damage. The purpose of this study was to examine the effect of predatory ants on the natural infestation of sugarcane top borer across five varieties of sugarcane, thereby filling a void in the current research concerning the screening of shoot-borer resistance. The study was conducted in sugarcane plantation at Asembagus, East Java, Indonesia. The symptoms of shoot borer infestation on leaves and dead hearts, as well as the number of predatory ants on the sample units were recorded. Top borer infestations varied in intensity across all five sugarcane varieties. Predatory ants and the survival rate of S. excerptalis neonate larvae were closely correlated. Among the five sugarcane varieties, BL had the lowest number of predatory ants and was the most favorable environment for top borer neonate larvae. Predatory ants play a significant role in determining the fate of the shoot borer on sugarcane plants and provide insight into a variety's susceptibility.