Annals of Applied Biology (1997) 131, 63-77

M.C. Smith, J. Rutter, P.J.A. Burt, F. Ramirez and E.H. Gonzalez O. (1997)
Black Sigatoka disease of banana: spatial and temporal variability in disease development
Annals of Applied Biology 131 (1), 63-77
Abstract: Field observations of black Sigatoka disease symptom development were made on banana plants from four sites (30 m apart) within an unsprayed plantation of dimensions 100 m x 200 m in Costa Rica during two field visits: October 1993 - February 1994 (wet to dry season) and April-September 1995 (dry to wet season). From these observations, estimates of the symptom-free period and the average rate of symptom development (during the symptomatic phase) were made for each leaf. No significant differences were found between sites in rates of symptom development in either 1993/94 or 1995, or in symptom-free period for 1993/94 (data-were not suitable to test for between-site differences in symptom-free period for 1995). This suggests that forecasts would not have to take into account differences in location within this small plantation. Symptom-free time decreased over the 1995 observation period, was less than in 1993/94 and correlated with increases in hours per day at a relative humidity (r.h.) of 100%. Because plantations may be sprayed many times per year, forecasts have to be sensitive to short-term changes in disease severity. Seasonal trends in some more rapidly and easily assessed characters (number of disease-free leaves, disease scores of specific leaves and average disease scores of entire plants) accurately reflected trends in the more detailed observations of symptom severity, hours per day at 100% r.h. and numbers of leaves unfurling per unit time. This suggests that these could be used as indicators of changes in disease severity in a forecasting scheme.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Peter J.A. Burt

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pseudocercospora fijiensis	Banana/plantain (Musa)	Costa Rica