Dispersal of Airborne Spores of Boll-Rotting Fungi and the Incidence of Cotton Boll Rot

Abstract

A Kramer-Collins Spore Sampler was operated in cotton intervals throughout the season. Spore counts increased soon fields at several locations in Louisiana during 1974 and 1975 after the onset of flowering, with peak spore catches approxto monitor the spore dispersal of boll-rotting fungi. Conidia imately 50 days later. Spore numbers decreased rapidly after of Alternaria gossypina, Curvularia spp., Diplodia the peak periods of spore dispersal. The first rotted bolls were gossypina, Fusarium spp., and Helminthosporium gossypii observed soon after the time of peak spore catches. With the were counted in hourly samples taken over 24-hr periods at exception of Alternaria, most spores were detected at night.

Influence of Southern Green Stink Bug,Nezara viridulaL., on Late-Season Yield Losses in Cotton,Gossypium hirsutumL.

“…Both pathogens are documented as causal agents for boll rot in Louisiana and across the southeastern United States (Sanders andSnow 1978, Kirkpatrick andRothrock 2001). Sanders and Snow (1978) documented the conidia of Alternaria gossypina, Curvularia spp., Helminthosporium gossypii, Diplodia gossypina, and Fusarium spp. in airborne samples in Louisiana cotton Þelds from 1 wk after ßowers Þrst appeared through harvest.…”

“…Boll rot has been reported to occur at higher levels within lower portions of a plant canopy (Snow et al 1981). Sanders and Snow (1978) have shown that Diplodia spp. and Fusarium spp.…”

Nitrogen effect on position of harvestable bolls in cotton

“…Nitrogen affects plant size and yield (Guinn, 1982;Howard and Hoskinson, 1986;Lutricketal., 1986;Maples and Frizzell, 1985;Mauney, 1986;Phillips et al, 1987;Thorn and Spurgeon, 1982;Touchtonetal., 1981;Wadleigh, 1944) and the number, size, and disposition of cotton bolls (Boquest et al, 1993(Boquest et al, , 1994Roncadorietal., 1975;Sanders and Snow, 1978). Mapping boll distribution and characteristics in cotton is tedious and information is limited on how N affects these parameters in the plant canopy.…”

Review: Nitrogen Utilization Features in Cotton Crop

“…In contrast, N ratio (40% PPA + 20% PBA) delayed the squaring and flowering, but promoted an earlier opening stage, so shortened the boll setting and filling period. Zhao et al, (2012) [45] concluded that as the flowering date is delay, fiber length and strength first increased and then decreased, fiber maturity and micronaire decreased N application increase boll number per plant and slight increase boll weight by the application at various rates and split ratio, Sawan et al 2006 [46] explained the increasing in boll weight may be due to increase in N rate and increases mineral uptake, photosynthetic assimilation and accumulation in sinks in the other hand high N rates have been linked to increased incidence of boll rot which has been attributed to additional vegetative growth that traps moisture underneath the canopy and increases infection [47] [48]. Dong et al (2012) [34] reported that increasing the N rate to 225 or 300 kg•ha −1 improved the boll size by 4.8% or 3.5% relative to the low N rate.…”