Melvin R. Hall

Root diseases, weeds, and nematodes with poultry litter and conservation tillage in a sweet corn–snap bean double crop

Abstract The effect of continuous applications of poultry litter on root diseases, nematodes, and weeds with different tillage practices in vegetable production in Georgia was investigated. Litter treatments (noncomposted and composted broiler or breeder litter) applied 3–5 weeks before planting were compared with no litter. In sweet corn and snap bean there were differences among years, and tillage and litter treatments had a variable effect on yield, post-emergence damping-off and plant stand. Crown and brace root rot in corn induced by Rhizoctonia solani AG 2-2 increased after 3 years conservation tillage, but there were no differences among litter treatments. Population densities of R. solani AG-4 were increased by conservation tillage before planting snap bean the first year but not in later years, while litter treatments had no effect. After 3 years, populations of Pythium spp., Fusarium solani, and Fusarium spp. did not differ among treatments, but noncomposted broiler litter increased populations of saprophytic fungi in soil compared with no litter. Population densities of stylet-bearing nematodes were low and usually not different among treatments. After 3 years of sweet corn populations of Meloidogyne incognita increased with conventional tillage compared with conservation tillage, populations of Paratrichodorus christiei were reduced by litter treatments and populations of Helicotylenchus dihystera were reduced by noncomposted broiler litter compared with no litter. Weed infestation increased in both tillage systems with time, but in snap bean there was a greater infestation in conservation tillage than in conventional tillage. Litter treatments had little effect on weed infestation.

Influence of cultivar and primed or germinated seed on stand establishment of watermelon in soil infested with Pythium irregulare or Rhizoctonia solani AG-4

Abstract In 1990 and 1991, primed, germinated, and untreated watermelon [ Citrullus lanatus (Thunb.) Matsum & Nakai] seeds of three cultivars were planted in March and April to evaluate the influence of these seed treatments on damping-off incited by Pythium irregulare and Rhizoctonia solani AG-4. One week after seeding in 1990, plant stand was greater from primed and germinated than untreated seeds in noninfested soil and greater from primed seeds than from germinated or untreated seeds in soil infested with P. irregulare . By 2 weeks after planting, seed treatments did not influence stand counts in non-infested soil. However, in soil infested with P. irregulare , stand counts were greater from primed seeds than from untreated seeds. In 1991, plant stands were not influenced with germinated seeds but were lower with primed seed, compared with untreated seeds, in non-infested soil or in soil infested with P. irregulare . Plant stand was greater from the April than the March planting in 1990, but this condition existed for only 1 week after planting in 1991. Neither germinated nor primed seeds improved plant establishment in soil infested with R. solani AG-4. Plant establishment was more consistent from cv. Crimson Sweet than from cvs Jubilee or Charleston Gray for the 2 years, but cultivar differences in response to P. irregulare or R. solani AG-4 were not detected. Primed watermelon seeds may enhance stand establishment in soil infested with P. irregulare when soil temperature at planting is suboptimal to optimal for watermelon seed germination and growth.