Study of dynamics of sugarcane aphid populations in south Texas region

The sugarcane aphid (Melanaphis saccchari; SCA) is an invasive pest of many field crops including sugarcane (Saccharum officinarum) and sorghum (Sorghum bicolor). SCA can persist under harsh environmental conditions by overwintering on alternate hosts and spread rapidly across different locations by forming alate morphs. The rapid spread along with huge losses caused by this pest has led to the increased use of pesticides and resistant cultivars which has also led to potential emergence of new virulent biotype/s. However, few studies have estimated the population dynamics of SCA from different locations in South Texas region which has also been a focal region for the outbreak of SCA. To understand this, we collected SCA from three different locations in Lower Rio Grande Valley and did a comprehensive work up on their morphology, life history traits, feeding behavior and host plant defense response. Through examining life history traits, including generation time, net reproductive rate, and intrinsic rate of increase fundamental differences in the populations may be identified. Further, Electrical Penetration Graph (EPG) was also used to assess the feeding behavior of SCA on sorghum-sudan grass (Sorghum drummondii) including time to first probe, time spent on phloem, xylem and non-probing phase. Preliminary analyses is underway and will be discussed in the light of possible SCA biotype development in South Texas.