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Title of Thesis

Prediction Of Cotton Leaf Curl Virus Disease And Its Vector Based On Epidemiological Factors And Its Management

Author(s)

Safdar Ali

Institute/University/Department Details
Department Of Plant Pathology, Faculty Of Agriculture / University Of Agriculture, Faisalabad
Session
2011
Subject
Plant Pathology
Number of Pages
148
Keywords (Extracted from title, table of contents and abstract of thesis)
Leaf, Management, Vector, Prediction, Factors, Disease, Epidemiological, Virus, Curl, Cotton, Treatments, Effective, Population, Resistant

Abstract
Cotton is an important commercial crop of global importance.Cotton is known as the backbone of Pakistan’s economy.Cotton leaf curl virus disease (CLCuVD) is a seriou  threat to the successful cotton production and is transmitted by whitefly Bemisia tabaci Gennadius under field conditions.A disease and vector predictive model based on 5 years epidemiological factors was developed and validated based on 2 years epidemiological factors for the prediction of CLCuVD and its vector. Y= 145+ 4.47x1-0.151x2-0.490x3-1.83x4+1.58x5-4.84x6 R2= 0.79 (Five years data) Y= 145+ 2.78x1 - 0.998 x2-0.400 x3-1.02 x4+3.85 x5-2.25 x6 R2= 0.75 (Two years data) Where y = CLCuVD, x1= Minimum temperature, x2 = Rainfall, x3 = Relative humidity, x4 = Wind velocity, x5 = Whitefly, x6 = Maximum temperature. Y= 57.0 - 0.370x1- 0.0853x2-0.297x3+0.813x4-0.565x5 R2= 0.64 (Five years data) Y= 27.5-0.726x1-0.511x2-0.122x3-0.177x4+0.639 x5 R2= 0.58 (Two years data) Where y = Whitefly, x1= Maximum temperature, x2 = Minimum temperature, x3 = Relative humidity, x4 = Rainfall, x5 = Wind velocity.A significant (P<0.05) but negative correlation was observed between maximum temperature and CLCuVD. The value of the coefficient of correlation was observed in the following order: 2006 (r=0.80*) < 2004 (r=0.79*) < 2005 (r=0.76*) <2002 (r=0.61*) and < 2003 (r=0.60*). Except 2006, the relationship of CLCuVD with rainfall was found nonsignificant during the subsequent years (r < 0.47). Wind velocity was found nonsignificant but negatively correlated with CLCuVD.Whitefly had significant and positive correlation with CLCuVD during all the five years. The relative humidity contributed significantly in the build up of whitefly population during 2005 only (r=0.60). During rest of the years relative humidity did play a prominent role in the spread of this vector as was evident from the value of correlation coefficient 0.34 ≤ r ≤ 0.47.The wind velocity did not contributed as effectively as compared to other variables.None of the screened varieties/advanced lines was found to be immune against cotton leaf curl virus disease and varied greatly in response to disease incidence during both the years (2007-08). Only three varieties/advanced lines (NIBGE-2, PB-899, NIAB- 884) were found to be highly resistant against CLCuVD. Eight cultivars (BH-162, NIAB- 824, CIM-496, MJ-7, CIM- 446, CIM-473, VH-148, Alseemi hybrid) were found to be resistant. Six varieties/advanced lines (NIAB-111, PB- 897, FH-2925, CIM-438, CIM-497, FH-115) were found moderately resistant. Five cultivars (FH-900, CIM-707, CIM-506, FH-901, CIM-498,) were observed to be moderately susceptible and five varieties/advanced lines (PB-843, FH-1000, BH-163, CIM-482, CIM-443) exhibited susceptible response.Five varieties/advanced lines (CIM-534, FH-2000, FH-2006, MNH-732, S-12) were found to be highly susceptible against cotton leaf curl disease, respectively. All the treatments reduced whitefly population and CLCuVD incidence significantly compared to untreated control.Azadirachta indica (Neem) extract was the most active to manage the B. tabaci population. Salicylic acid was at number second and Eucalyptus globules (Sufaida) was at number third whereas Allium sativum (Garlic) and Calotropics procera (Ak, Akund) were at number four and fifth respectively in managing the B. tabaci and CLCuVD.Aloe babadensis (Aloe) and Datura stramonium (Datura) were found less effective compared to other treatments.

Download Full Thesis
727 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

iii
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2

1

INTRODUCTION


 

1
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3 2 REVIEW OF LITERATURE

2.1 Clcuvd In Historical Perspective
2.2 Cotton Leaf Curl Virus And Its Genome
2.3 Geminiviruses
2.4 Clcuvd Incidence, Symptomology, Host Range And Transmission
2.5 Environmental Conditions Conducive For Clcuvd And Whitefly Population

6
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4 3 MATERIALS AND METHODS

3.1 Development Of A Clcuvd And Vector Predictive Model Based On 5 Years Data (2002-2006)
3.2 Collection Of Environmental Conditions Data
3.3 Collection Of Whitefly Population Data
3.4 Validation Of Model By 2 Years Data (2007-2008)
3.5 Confirmation Of The Virus
3.6 Area Under Disease Progress Curve
3.7 Management
3.8 Statistical Analysis

17
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5 4 RESULTS

4.1 Development Of Clcuvd And Whitefly Predictive Models Based On Five Years Data
4.2 Comparison Of Environmental Variables Of Five Years And Characterization Of Conducive Environmental Conditions For The Development Of Clcuvd And Whitefly
4.3 Correlation By Years Of Environmental Variables With Clcuvd And Bemisia Tabaci (2002-2006)
4.4 Clcuvd Predictive Model Based On Five Years Data (2002-2006)
4.5 Clcuvd Predictive Model Based On Two Years Data (2007-2008)
4.6 Correlation Of Weekly Environmental Conditions With Clcuvd And Bemisia Tabaci During The Two Years (2007-2008)
4.7 Correlation Of Environmental Factors With Clcuvd Incidence And Whitefly Population On Different Advanced Lines/varieties During 2007-08
4.8 Clcuvd Predictive Model Based On Two Years Data (2007-2008)
4.9 Clcuvd Model Validation
4.10 Whitefly Predictive Model Based On Five Years Data (2002-2006)
4.11 Whitefly Predictive Model Based On Two Years Data (2007-2008)
4.12 Whitefly Model Validation
4.13 Characterization Of Critical Ranges Of Environmental Conditions Conducive For Clcuvd Development And Whitefly Population Buildup On Four Cotton Varieties During 2007-08
4.14 Management

24
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6 5 DISCUSSION

 

75
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7 6 SUMMARY

 

79
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8 7 LITERATURE CITED

82
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