ARS | Publication request: Erianthus: A sugarcane relative with potential as a source of resistance to the stem borer Diatraea saccharalis (Lepidoptera: Crambidae)

Submitted to: International Society of Sugar Cane Technologists Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 21, 2013
Publication Date: N/A

Interpretive Summary: Insects whose larvae tunnel into the sugarcane stalk are important pests in many sugarcane industries around the world. Integrated pest management (IPM) strategies are frequently employed to control damaging infestations of these insects. Among those control strategies is growing pest resistant varieties. Unfortunately, those traits that impart resistance often cause reductions in yield potential. For this reason, new sources of resistance that are not associated with yield reduction are sought. We identified a close relative to sugarcane that possessed dense hairs around the leaf collar that appeared to prevent young stem borer larvae from getting behind the leaf sheath and ultimately boring into the stalk. We evaluated a group of six individuals from this group of relatives in both the greenhouse and laboratory. Our results in both the greenhouse and laboratory showed that these hairs do indeed impede larva movement and therefore reduce damage. We must now determine if these collar hairs can be transmitted to high yielding varieties in a density that imparts stem borer resistance. If ultimately successful, the hair trait can represent significant savings to sugarcane growers in insecticide costs as well as reducing the amount pesticides going into the environment.

Technical Abstract: Plant resistance can play an important role in IPM strategies to reduce damage from infestations of stem borers. However, resistance, when it is present, is often negatively associated with yield potential. There exists then, a need to identify sources of resistance that have no adverse effect on sugar yield. Clones of the genus Erianthus, a taxa of sugarcane that possess leaf insertion (throat) hairs, may provide that source of resistance. We evaluated six Erianthus accessions in the glasshouse and laboratory to determine if these throat hairs represent a barrier to young Diatraea saccharalis (Lepidoptera: Crambidae) larvae and thereby confer resistance. Laboratory evaluations showed that the throat hairs represent a physical barrier to young larvae, because after 30 minutes test larvae were unable to successfully negotiate those accessions with dense throat hairs. However, larvae were able to easily negotiate hairs on those accessions with less dense hair patterns. The laboratory findings were reflected in glasshouse studies that showed fewer larvae were recovered after 21 days of feeding and less stalk tunneling on infested plants. Before this trait can be successfully exploited, additional research is needed to determine if the leaf throat hairs can be transmitted to high yielding cultivars in a form (both density and form) that confers resistance.