Doctor of Philosophy (PhD)
Plant viruses are an important component of agro-ecosystems and the knowledge of impacts they can cause on their hosts, and on different vectors and non-vector herbivores associated with the hosts, is very crucial in devising sound management strategies for virus disease and vector control in the landscape. The interactions between these components, however, are difficult to predict and vary according to the system under investigation. In order to understand some of these interrelationships, different sets of experiments were carried out in three different pathosystems to look at the impacts of plant viruses on vector and non-vector herbivores. Firstly, in Sorghum mosaic virus (SrMV)-sorghum (Sorghum bicolor L.) pathosystem, we found that Melanaphis sacchari (Zehntner) was attracted to virus infected sorghum but the population was negatively affected upon feeding on virus infected sorghum. Moreover, M. sacchari unlike Myzus persicae (Sulzer), failed to transmit SrMV, and we state based on our results that M. sacchari is a non-vector of SrMV. In Cucumber mosaic virus (CMV) and Sunn-hemp mosaic virus (ShMV) infected cowpea (Vigna unguiculata (L.) Walp), oviposition by adult Chrysodeixis includens (Walker) and Spodoptera frugiperda (Smith) was negatively affected whereas S. frugiperda larva benefitted upon feeding on CMV-infected host tissue. In our study with Bell pepper endornavirus (BPEV) in bell pepper (Capsicum annuum L.), we observed that M. persicae preferred virus-free leaves and performed poorly on virus infected leaf tissues. The mixed results we obtained on the impacts of plant viruses in different systems suggest that it is difficult to draw a general conclusion and the interactions are complex, diverse, and virus-insect specific.
Paudel, Sunil, "Effects of Plant Viruses on Vectors and Non-vector Herbivores in Three Different Pathosystems" (2019). LSU Doctoral Dissertations. 4870.