Effects of plant spacing, inoculation date, and peanut cultivar on epidemics of peanut stem rot and tomato spotted wilt

• Published in: Plant disease Vol. 89; no. 9; pp. 969 - 974
• Main Authors: Sconyers, L.E, Brenneman, T.B, Stevenson, K.L, Mullinix, B.G
• Format: Journal Article
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01.09.2005
• Subjects: Arachis hypogaea; Biological and medical sciences; Corticium rolfsii; cultivars; disease incidence; disease outbreaks; disease severity; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; fungal wilt; host plants; Lycopersicon esculentum; microclimate; peanuts; Phytopathology. Animal pests. Plant and forest protection; plant pathogenic fungi; row spacing; Sclerotium rolfsii; Solanum lycopersicum var. lycopersicum; stem rot; tomatoes; Georgia; Florida; United States; North America; America; Disease development; Irrigation; Temperature; Microbiology; Epidemiology; Incidence; Fungi; Dicotyledones; Angiospermae; Lycopersicon esculentum; Fungi Imperfecti; Solanaceae; disease severity; Thallophyta; Epidemic; Arachis hypogaea; Sclerotium rolfsii; Sensitivity; Treatment; Leguminosae; Vegetable crop; disease incidence; Spermatophyta; Severe; Oil plant (vegetal); Cultivar
• ISSN: 0191-2917; 1943-7692
• DOI: 10.1094/PD-89-0969

Two microplot studies were conducted with peanut (Arachis hypogaea L.) in 2000, 2001, and 2002 to determine the effects of plant spacing, inoculation date, and cultivar on stem rot development caused by Sclerotium rolfsii Sacc., tomato spotted wilt incidence, and microclimate (temperature and relative humidity). Stem rot severity and incidence decreased as plant spacings were increased in 5-cm increments from 5 to 30 cm. Two cultivars with similar susceptibility but different growth habits were compared. Perhaps due to heavy irrigation and extensive vegetative growth, stem rot was similar for 'Florida MDR-98' and 'Georgia Browne'. Plants inoculated later in the year (90 days after planting [DAP]) had less disease at harvest, but often developed more severe symptoms within the first week of inoculation than plants inoculated at 50 or 70 DAP. Canopy microclimate was different than ambient conditions for all treatments; however, differences among treatments were inconsistent and did not explain differences in disease among spacings. Generally, as plant spacing decreased and plant population increased, stem rot increased and tomato spotted wilt was reduced. These data demonstrate that the physical spacing between plants is a critical factor in disease development.