Paper · 2011 · Plant Pathology

Comparison of disease patterns assessed by three independent surveys of cassava mosaic virus disease in Rwanda and Burundi

H. Bouwmeester; G. B. M. Heuvelink; J. P. Legg; et al.

13
claims
33
verbatim quotes
15
citations
2
research areas
—
Not open access

Abstract

Cassava mosaic disease (CMD) seriously affects cassava yields in Africa. This study compared the spatial distribution of CMD using three independent surveys in Rwanda and Burundi. Geostatistical techniques were used to interpolate the point‐based surveys and predict the spatial distributions of different measures of the disease. Correlative relationships were examined for 35 environmental and socio‐economic spatial variables of which 31 were correlated to CMD intensity, with the highest correlation coefficients for latitude (−0·47), altitude (−0·36) and temperature (+0·36). The most significant explanatory variables were entered in separate linear regression models for each of the surveys. The models explained 54%, 44% and 22% of the variation in CMD. The residuals of the regression models were interpolated using kriging and added to the regression models to map CMD across both countries. Significant differences were calculated in some areas after correcting for interpolation error. An important explanation of the differences is interaction between the CMD pandemic and the dates of the three surveys. Large relative prediction errors obtained in the regression kriging procedure show the need to improve the survey design and decrease measurement error. Improved maps of crop diseases such as CMD could aid targeting of control interventions and thereby contribute to increasing crop yields. This study validated the unique character of each of the survey approaches adopted and underlines the importance of specific interpretation of results for CMD management. The study emphasizes the need for optimization of sampling designs and survey protocols to maximize the potential of regression kriging.

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Claims 13

Associationobservedoriginal resultmeasured

Claim · model-written summary

31 of 35 environmental and socio-economic variables were correlated with cassava mosaic disease intensity.

Outcome
CMD intensitye1
Direction
correlatede1
Value
31e1
Setting
Rwanda and Burundie0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e0

“using three independent surveys in Rwanda and Burundi”

✓ located verbatim in the source · abstract, characters 125–178 · show in text ↑
e1

“of which 31 were correlated to CMD intensity”

✓ located verbatim in the source · abstract, characters 429–473 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Latitude had the highest correlation coefficient with cassava mosaic disease intensity, -0.47.

Outcome
CMD intensitye1
Direction
higheste2
Value
−0·47e2
Setting
latitudee2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e1

“of which 31 were correlated to CMD intensity”

✓ located verbatim in the source · abstract, characters 429–473 · show in text ↑
e2

“with the highest correlation coefficients for latitude (−0·47), altitude (−0·36) and temperature (+0·36)”

✓ located verbatim in the source · abstract, characters 475–579 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Altitude had a high correlation coefficient with cassava mosaic disease intensity, -0.36.

Outcome
CMD intensitye1
Direction
higheste2
Value
−0·36e2
Setting
altitudee2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e1

“of which 31 were correlated to CMD intensity”

✓ located verbatim in the source · abstract, characters 429–473 · show in text ↑
e2

“with the highest correlation coefficients for latitude (−0·47), altitude (−0·36) and temperature (+0·36)”

✓ located verbatim in the source · abstract, characters 475–579 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Temperature had a high correlation coefficient with cassava mosaic disease intensity, +0.36.

Outcome
CMD intensitye1
Direction
higheste2
Value
+0·36e2
Setting
temperaturee2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e1

“of which 31 were correlated to CMD intensity”

✓ located verbatim in the source · abstract, characters 429–473 · show in text ↑
e2

“with the highest correlation coefficients for latitude (−0·47), altitude (−0·36) and temperature (+0·36)”

✓ located verbatim in the source · abstract, characters 475–579 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

The regression model explained 54% of the variation in cassava mosaic disease.

Treatment
most significant explanatory variablese4
Outcome
variation in CMDe3
Value
54%e3

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e3

“The models explained 54%, 44% and 22% of the variation in CMD”

✓ located verbatim in the source · abstract, characters 699–760 · show in text ↑
e4

“The most significant explanatory variables were entered in separate linear regression models for each of the surveys”

✓ located verbatim in the source · abstract, characters 581–697 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

The regression model explained 44% of the variation in cassava mosaic disease.

Treatment
most significant explanatory variablese4
Outcome
variation in CMDe3
Value
44%e3

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e3

“The models explained 54%, 44% and 22% of the variation in CMD”

✓ located verbatim in the source · abstract, characters 699–760 · show in text ↑
e4

“The most significant explanatory variables were entered in separate linear regression models for each of the surveys”

✓ located verbatim in the source · abstract, characters 581–697 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

The regression model explained 22% of the variation in cassava mosaic disease.

Treatment
most significant explanatory variablese4
Outcome
variation in CMDe3
Value
22%e3

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e3

“The models explained 54%, 44% and 22% of the variation in CMD”

✓ located verbatim in the source · abstract, characters 699–760 · show in text ↑
e4

“The most significant explanatory variables were entered in separate linear regression models for each of the surveys”

✓ located verbatim in the source · abstract, characters 581–697 · show in text ↑
Observationobservedoriginal resultsignificant (as stated)measured

Claim · model-written summary

Significant differences in cassava mosaic disease mapping were calculated in some areas after correcting for interpolation error.

Outcome
Significant differencese5
Qualifier
in some areas after correcting for interpolation errore5

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e5

“Significant differences were calculated in some areas after correcting for interpolation error”

✓ located verbatim in the source · abstract, characters 902–996 · show in text ↑
Mechanismauthor interpretationoriginal resultbasis n/a

Claim · model-written summary

Interaction between the CMD pandemic and the dates of the three surveys is an important explanation of the differences between surveys.

Outcome
differencese6
Qualifier
interaction between the CMD pandemic and the dates of the three surveyse6

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e6

“An important explanation of the differences is interaction between the CMD pandemic and the dates of the three surveys”

✓ located verbatim in the source · abstract, characters 998–1116 · show in text ↑
Method / resourceobservedoriginal resultnegativemeasured

Claim · model-written summary

Relative prediction errors of the regression kriging procedure were large.

Outcome
relative prediction errorse7
Value
Largee7

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e7

“Large relative prediction errors obtained in the regression kriging procedure show the need to improve the survey design and decrease measurement error”

✓ located verbatim in the source · abstract, characters 1118–1269 · show in text ↑
Recommendationauthor interpretationoriginal resultpositivebasis n/a

Claim · model-written summary

The authors recommend improving the survey design and decreasing measurement error.

Outcome
improve the survey design and decrease measurement errore7

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e7

“Large relative prediction errors obtained in the regression kriging procedure show the need to improve the survey design and decrease measurement error”

✓ located verbatim in the source · abstract, characters 1118–1269 · show in text ↑

schema checkedfield values found in the cited quotesPermalinkReport an issue

Recommendationhypothesisoriginal resultpositivebasis n/a

Claim · model-written summary

Improved maps of cassava mosaic disease could aid targeting of control interventions.

Outcome
targeting of control interventionse0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e0

“Improved maps of crop diseases such as CMD could aid targeting of control interventions and thereby contribute to increasing crop yields”

✓ located verbatim in the source · abstract, characters 1271–1407 · show in text ↑

schema checkedfield values found in the cited quotesPermalinkReport an issue

Recommendationauthor interpretationoriginal resultpositivebasis n/a

Claim · model-written summary

The authors recommend optimizing sampling designs and survey protocols for regression kriging.

Outcome
optimization of sampling designs and survey protocolse0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Manihot esculenta
Manihot esculenta · Taxon葉子 · CC0 · iNaturalist ↗

Verbatim

t0

“cassava mosaic virus disease”

✓ located verbatim in the source · title, characters 72–100 · show in text ↑
e0

“The study emphasizes the need for optimization of sampling designs and survey protocols”

✓ located verbatim in the source · abstract, characters 1580–1667 · show in text ↑

schema checkedfield values found in the cited quotesPermalinkReport an issue