Effects of Cotton Leaf Crumple Virus on Cotton Inoculated at Different Growth Stages. J. K. Brown, Department of Plant Pathology, University of Arizona, Tucson 85721. J. D. Mihail, and M. R. Nelson. Department of Plant Pathology, University of Arizona, Tucson 85721. Plant Dis. 71:699-703. Accepted for publication 1 March 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0699.

The effects of cotton leaf crumple (CLC) disease on yield components and on symptom expression were examined for cotton plants inoculated at various growth stages. In a field test with three inoculation ages, infection at early and midgrowth stages significantly reduced plant height and yield. Yield losses were expressed as a decrease in the number of bolls set and as a delay in boll maturation. Among nine quality parameters evaluated, only boll weight was reduced as a result of virus infection. In a greenhouse test with five inoculation ages, total leaf area was significantly reduced as a result of virus infection. Regardless of plant age at inoculation, significant yield loss was observed in the form of a decrease in boll set and/or boll weight. Characteristic CLC symptoms were not expressed by plants inoculated at greater than the 14- to 16-leaf stage until midseason; thus, estimates of disease incidence that rely solely on the ability to detect foliar symptoms early in the season are not reliable, because latent symptom expression has not been taken into account.