The relationship between disease symptoms and parasite growth in bacterial blight of cotton

Abstract

SummaryLesion development and growth of Xanthomonas malvacearum (E. F. Smith) Dowson were followed in seedlings of different cultivars of cotton (Gossypium hirsutum L.) after inoculation of hypocotyls. There was a close relationship between numbers of the parasite and length of hypocotyl lesion. Disease development could be accurately determined by measurement of lesion length from 2 to 3 days after inoculation until growth of the parasite ceased. Growth patterns of the parasite in vivo took the form of a distinct period of exponential (phase 1) growth followed by relatively little, if any, further increase in numbers (phase 2 growth). The duration of phase 1 growth was related to host resistance and environmental factors.