Transmission characteristics of banana bunchy top virus to banana Pentalonia nigronervosa Coq.

Abstract

Understanding the basic of transmission characteristics of any vector born pathogen is the critical if the disease system is to be understood, further it is of up most importance for the creation of any control strategy. It is critical to understand ail aspects of a plant pathogenic virus's biology and how it changes in each environment in order to control its spread. Temperature and insect stage can profoundly change key aspects in viral transmission (TBA). My work on the basic biology of the virus/vector interactions expands on the work that was started over 80 years ago. In Chapter 2, I present work on temporal aspects of BBTV transmission in relation to its vector and host plant I specifically sought to determine how long it took for P. nigronervosa to transmit BBTV after acquisition (Le. the latent period within the insect). To answer this question I conducted studies utilizing classical transmission experiments. The latent period within the plant is the second component of this chapter. The goal was to determine the earliest date a plant begins to act as a source of the virus after inoculation. There have been no studies to determine the vector latent period of any viruses in the family Nanoviridae. The latent period within plant is a neglected area of viral research, specifically with BBTV. The focus of Chapter 3 is to determine how temperature and aphid life stage affect BBTV transmission. I sought to objectively determine how these factors quantitatively affect transmission. The first experiment was an investigation to determine if there are any differences in BBTV transmission by nymph and adults and to determine the impact of temperature on viral transmission efficiency. I tested the effect of three different temperatures (20°, 25°, 30°C) on acquisition and inoculation of BBTV by adult aphids as compared with third instar nymphs. Other experiments were conducted to determine if temperature has a different effect on BBTV acquisition and inoculation efficiency by aphids and what the effect of plant access period on transmission efficiency by adults. Throughout this work, two major components of virus transmission were analyzed. What the latent period of BBTV is within the plant and its aphid vector was determined. This will help improve IPM sampling plan. The second part of my research focused on determining how temperature and the aphid's life stage effects BBTV transmission. I expect both components of my work to improve current knowledge on the biology of circulative, non-propagative plant viruses by aphid vectors.