Title page for ETD etd-020199-125601


Type of Document Dissertation
Author Mwangi, Symon Munanda
Author's Email Address smwangi@vt.edu
URN etd-020199-125601
Title STATUS OF NORTHEN LEAF BLIGHT, Phaeosphaeria maydis LEAF SPOT, SOUTHERN LEAF BLIGHT, RUST, MAIZE STREAK VIRUS AND PHYSIOLOGIC SPECIALIZATION OF Exserohilum turcicum IN KENYA.
Degree PhD
Department Plant Pathology, Physiology, and Weed Science
Advisory Committee
Advisor Name Title
Warren, Herman L. Committee Chair
Eisenback, Jonathan D. Committee Member
Griffin, Gary J. Committee Member
Maroof, M. A. Saghai Committee Member
Stipes, R. Jay Committee Member
Keywords
  • Phaeosphaeria
  • Puccinia
  • Exserohilum
  • Bipolaris.
Date of Defense 1998-11-30
Availability unrestricted
Abstract
STATUS OF NORTHERN LEAF BLIGHT, Phaeosphaeria maydis LEAF SPOT, SOUTHERN LEAF BLIGHT, RUST, MAIZE STREAK VIRUS AND PHYSIOLOGIC SPECIALIZATION OF Exserohilum turcicum IN KENYA

Symon F. M. Mwangi

Herman L. Warren, Chairman

(ABSTRACT)

Exserohilum turcicum, Phaeosphaeria maydis, Bipolaris maydis, Puccinia polysora, Puccinia sorghi and maize streak virus were the most serious maize pathogens found in Kenya during a 1995/96 survey of 65 farms representing all the agro-ecological zones. Exserohilum turcicum - induced blight was observed in all maize producing areas with disease incidence reaching over 45%. Lesions were sometimes over 400 mm long by 25 mm in width. Southern leaf blight caused by Bipolaris maydis was most severe in the Kenyan maize granary located in the highlands west of the Rift Valley where it occurred alone or with Phaeosphaeria maydis leaf spot. Incidences of over 75% were recorded for southern leaf blight and Phaeosphaeria maydis leaf spot in western Kenya and over 85% for Phaeosphaeria maydis leaf spot in Thika, Nyeri, Muranga and Kirinyaga Districts of Central Province. Common rust caused by Puccinia sorghi was equally severe in the areas of Molo, Njoro and Bahati in Nakuru District with severity levels of over 65%. Lowland rust caused by Pucinia polysora was important in the coastal region with over 75% disease severity in Kwale District. Traces of lowland rust were observed in Kirinyaga District. Maize streak virus was severe in the Lake Victoria region of western Kenya, central areas of Kenya and in the Coast. This disease was severe where Napier grass (Pennisetum purpureum) with streak like symptoms was near the infected maize plots. Individual cultures of Exserohilum turcicum were not appreciably different in appearance but varied in growth rates at 22oC. A total of nineteen isolates of Exserohilum turcicum were classified into races using the Ht gene bearing maize differential inbred lines. Three isolates were race 0, three were race 1, one was race 2, one was race 3, two isolates were race 12, and eight did not fit in the known classification. These were named and grouped as k1, k2 and k3. The k3 race was virulent to HtN gene only. Four Kenyan and two American lines were inoculated with eight isolates of Exserohilum turcicum. All the Kenyan lines were susceptible to the isolates used. Tables of means comparisons and figures for disease occurrence and severity are provided. This is the first time disease prevalence and severity has been documented for maize in Kenya.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  APPENDIXA.pdf 74.94 Kb 00:00:20 00:00:10 00:00:09 00:00:04 < 00:00:01
  appendixb1.pdf 76.75 Kb 00:00:21 00:00:10 00:00:09 00:00:04 < 00:00:01
  appendixb2.pdf 78.91 Kb 00:00:21 00:00:11 00:00:09 00:00:04 < 00:00:01
  appendixb3.pdf 82.88 Kb 00:00:23 00:00:11 00:00:10 00:00:05 < 00:00:01
  appendixb4.pdf 28.98 Kb 00:00:08 00:00:04 00:00:03 00:00:01 < 00:00:01
  appendixC.pdf 57.71 Kb 00:00:16 00:00:08 00:00:07 00:00:03 < 00:00:01
  CHAPTER1.pdf 53.91 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  CHAPTER2.pdf 53.67 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  chapter2Figure1.pdf 80.80 Kb 00:00:22 00:00:11 00:00:10 00:00:05 < 00:00:01
  chapter2Figure11-12.pdf 58.85 Kb 00:00:16 00:00:08 00:00:07 00:00:03 < 00:00:01
  chapter2Figure13-14.pdf 57.94 Kb 00:00:16 00:00:08 00:00:07 00:00:03 < 00:00:01
  chapter2Figure15-16.pdf 118.28 Kb 00:00:32 00:00:16 00:00:14 00:00:07 < 00:00:01
  chapter2Figure17-18.pdf 48.47 Kb 00:00:13 00:00:06 00:00:06 00:00:03 < 00:00:01
  chapter2Figure19.pdf 122.84 Kb 00:00:34 00:00:17 00:00:15 00:00:07 < 00:00:01
  chapter2figure2.pdf 120.95 Kb 00:00:33 00:00:17 00:00:15 00:00:07 < 00:00:01
  chapter2Figure20-21-22.pdf 106.35 Kb 00:00:29 00:00:15 00:00:13 00:00:06 < 00:00:01
  chapter2Figure3.pdf 222.18 Kb 00:01:01 00:00:31 00:00:27 00:00:13 00:00:01
  chapter2Figure4.pdf 53.87 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  chapter2Figure5.pdf 76.13 Kb 00:00:21 00:00:10 00:00:09 00:00:04 < 00:00:01
  chapter2Figure6.pdf 364.43 Kb 00:01:41 00:00:52 00:00:45 00:00:22 00:00:01
  chapter2Figure7.pdf 110.31 Kb 00:00:30 00:00:15 00:00:13 00:00:06 < 00:00:01
  chapter2Figure8.pdf 86.37 Kb 00:00:23 00:00:12 00:00:10 00:00:05 < 00:00:01
  chapter2Figure9-10.pdf 62.07 Kb 00:00:17 00:00:08 00:00:07 00:00:03 < 00:00:01
  chapter2tables.pdf 90.00 Kb 00:00:25 00:00:12 00:00:11 00:00:05 < 00:00:01
  CHAPTER3.pdf 64.13 Kb 00:00:17 00:00:09 00:00:08 00:00:04 < 00:00:01
  chapter3Figure1.pdf 53.51 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  chapter3Figure10.pdf 40.09 Kb 00:00:11 00:00:05 00:00:05 00:00:02 < 00:00:01
  chapter3Figure11.pdf 93.12 Kb 00:00:25 00:00:13 00:00:11 00:00:05 < 00:00:01
  Chapter3Figure12.pdf 47.81 Kb 00:00:13 00:00:06 00:00:05 00:00:02 < 00:00:01
  chapter3Figure13-14.pdf 87.65 Kb 00:00:24 00:00:12 00:00:10 00:00:05 < 00:00:01
  Chapter3Figure15-16.pdf 91.26 Kb 00:00:25 00:00:13 00:00:11 00:00:05 < 00:00:01
  chapter3Figure17.pdf 38.61 Kb 00:00:10 00:00:05 00:00:04 00:00:02 < 00:00:01
  chapter3Figure2.pdf 48.26 Kb 00:00:13 00:00:06 00:00:06 00:00:03 < 00:00:01
  chapter3Figure3.pdf 223.47 Kb 00:01:02 00:00:31 00:00:27 00:00:13 00:00:01
  chapter3Figure4.pdf 47.43 Kb 00:00:13 00:00:06 00:00:05 00:00:02 < 00:00:01
  chapter3Figure5-6.pdf 112.31 Kb 00:00:31 00:00:16 00:00:14 00:00:07 < 00:00:01
  chapter3Figure7-8-9.pdf 52.16 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  chapter3Tables.pdf 42.45 Kb 00:00:11 00:00:06 00:00:05 00:00:02 < 00:00:01
  CHAPTER4.pdf 49.03 Kb 00:00:13 00:00:07 00:00:06 00:00:03 < 00:00:01
  chapter4Figure1.pdf 43.56 Kb 00:00:12 00:00:06 00:00:05 00:00:02 < 00:00:01
  chapter4Figure2.pdf 21.35 Kb 00:00:05 00:00:03 00:00:02 00:00:01 < 00:00:01
  chapter4Figure3-4.pdf 47.87 Kb 00:00:13 00:00:06 00:00:05 00:00:02 < 00:00:01
  chapter4Figure5.pdf 51.65 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
  chapter4Tables.pdf 19.34 Kb 00:00:05 00:00:02 00:00:02 00:00:01 < 00:00:01
  TABLEOFCONTENTS.pdf 28.65 Kb 00:00:07 00:00:04 00:00:03 00:00:01 < 00:00:01
  TITLEPAGE.PDF 3.40 Kb < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01
  VITA.pdf 2.51 Kb < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.