Effect of Environmental Factors onSclerotinia minorand Sclerotinia Blight of Peanut

An Assessment of Environmental Conditions Preceding Outbreaks of Sclerotinia Blight of Peanut in Virginia1

“…New flushes of succulent plant growth at branch tips after irrigation are also a likely source of increased vulnerability to infection by S. minor (2,15). Observations in the current study and those of others (5,6,12) have indicated that mycelia from germinating sclerotia at the soil surface and near plant tissues (branches, pegs, leaves, etc.) were responsible for initiating infections in peanut fields.…”

“…In all cases, the infection sites were located beneath a dense foliar canopy that restricted air movement and shaded the infection site from direct sunlight. Dow et al (5) reported that the central main stem and lateral branches of peanut plants were equally susceptible to infection and colonization by S. minor. Their studies also demonstrated that relative humidities from 95 to 100% were required for germination of sclerotia on the soil surface.…”

“…Both air and soil temperature along with available moisture have been implicated as primary factors in determining disease onset in the field (5). Vine growth or specifically the covering of middles between rows and the density of the foliar canopy are thought to be important host factors (3,6).…”

Planting Density Influences Disease Incidence and Severity of Sclerotinia Blight in Peanut

“…Temperature, relative humidity, and soil moisture play vital roles in the infection and colonization of plant tissues by S. minor. Outbreak of Sclerotinia blight is most often observed after vines are within 15 cm of touching or after vines lap between rows (Dow et al, 1988b;Phipps, 1995). The disease is most severe during cool, wet weather, with an optimum growth range of 15 to 258C and a relative humidity approaching saturation (95-100%).…”

“…Sclerotinia minor is a soil-borne pathogen. During this time the plant canopies expand, contributing to the maintenance of higher humidity close to the ground (Dow et al, 1988b). High humidity promotes myceliogenic germination of sclerotia and is positively correlated with disease development (Dow et al, 1988a(Dow et al, , 1988b.…”