Studies of Nematodes Associated With Maize, Soybean, and Sunflower in Illinois and the Republic of Zambia

Field trials were established in the Republic of Zambia in soil fumigated with ethylene dibromide (EDB) and not fumigated, and planted with soybean ('Bragg', 'Jupiter', 'Santa Rosa' and 'Hernon 147'), sunflower ('CCA 81') and maize ('MM 603'). Parasitic nematodes identified were Pratylenchus zeae, Helicotylenchus pseudorobustus, Paratrichodorus christiei, Scutellonema brachyurum, Meloidogyne javanica and Tylenchorhynchus n. sp. Significantly higher populations of P. christiei in fumigated plots were associated with 16%, 10% and 6% yield decreases with soybean cvs. Bragg, Santa Rosa and Hernon 147, respectively. 'Jupiter' yields were 6% higher in fumigated plots. Control of M. javanica with fumigation increased sunflower yield by 56%. Increased maize yields were associated with fumigation and subsequent control of S. brachyurum. Infection of soybean roots with Neocosmospora vasinfecta var. africana was recorded for the first time in the Republic of Zambia in nonfumigated plots infested with S. brachyurum, M. javanica and Tylenchorhynchus sp. Population development of Heterodera glycines and Pratylenchus scribneri, alone and in combination, on 'Williams 82' soybean in 70 days at 20, 24, 28, and 32 C was determined in two experiments. Suppression of H. glycines in temperatures favoring P. scribneri suggests that temperature at the time of primary infection is important in determining the dominant species in interspecific competition between H. glycines and P. scribneri. Male:female ratios of H. glycines were highest when in combination with an initial 2,000 or 3,000 P. scribneri. No synergistic effects on plant growth due to concomitant infections of these nematodes were observed. Techniques for surface sterilization of P. scribneri were compared using streptomycin sulfate and either HgCl$\sb2$ or Ceresan Nass. Following axenization, gnotobiotic cultures of P. scribneri were established on carrot discs.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Plant Pathology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Lawn, Dennis Andrew

• Agriculture, Plant Pathology

Identifier

(UMI)AAI8815377

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70615