Niche competition between two subterranean early shoot borers of sugarcane, Chilo infuscatellus and Tetramoera schistaceana

Abstract

Several species of borers are associated with sugarcane in Indonesia, and they attack the plant from the early to the mature stage. Early shoot borers attack young plants, producing the dead-heart symptom as the growing point dies. Our study aims to understand the niche and behavior of borers attacking sugarcane during the early growth period. A purposive sampling was conducted to collect symptomatic plants from the fields in two consecutive cropping cycles. We studied the symptoms, position of the holes and the growing point, then we also made a competition experiment in the laboratory. The result showed that Chilo infuscatellus Snellen (Lepidoptera: Crambidae) and Tetramoera schistaceana Snellen (Lepidoptera: Tortricidae) were the main sugarcane early shoot borer species found, comprising 48 and 49%, respectively. The borers preferred to attack sugarcane with growing points below ground level, along with holes situated mostly under the soil surface, indicating their strong subterranean behavior. Both species utilized very similar niches, leading to very high niche overlap; ultimately, intense competition is more likely to occur. The laboratory competition experiment revealed that C. infuscatellus outcompeted T. shcistaceana.