Occurrence of Telenomus dignus (Gahan) on the Sugarcane Borers, Scirpophaga intacta Snellen and Chilo sacchariphagus Bojer in Guangxi Province, China

Abstract

Sugarcane (Saccharum officinarum L.) is an important crash crop in Guangxi, China. The sugarcane borers (Scirpophaga intacta Snellen and Chilo sacchariphagus Bojer) cause serious damage to sugarcane crop in Guangxi Province. Consequently, increasing attention has been given into the investigation and development of biocontrol agents to control these pests. The parasitoid wasp Telenomus sp. has previously been reported as a natural enemy of sugarcane borers in Guangxi Province. Telenomus dignus is the species found parasitizing borer eggs in field in Fujian Province, but it has not been previously mentioned as natural enemy of these pests. T. dignus was collected on S. intacta egg masses and identified from Shangsi County of Guangxi Province during 2013. In these studies, the parasitic behavior of T. dignus on eggs of S. intacta and C. sacchariphagus was investigated under field conditions during 2013–2014. The results from the current study showed that the percentage of parasitized egg masses of S. intacta parasitized by T. dignus was 45.71 and 57.14% in 2013 and 2014, respectively, while in C. sacchariphagus egg masses, the percentage of parasitism by T. dignus was 45.28 and 51.09% in 2014, respectively. The sex ratio (female/male) of T. dignus adults on S. intacta was 1.45:1 in 2013 and 5.17:1 in 2014 and was 2.17:1 on C. sacchariphagus in 2014. T. dignus was the dominant egg parasitoid of these two species of sugarcane borers in isolated sugarcane regions in Guangxi Province. Further investigations on biology of T. dignus are required to develop this parasitoid as a more widespread biocontrol agent of sugarcane borers.