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Noriega-Cantu, D. H., Teliz, D., Mora-Aguilera, G., Rodriguez-Alcazar, J., Zavaleta-Mejia, E., Otero-Colinas, G., and Campbell, C. L. 1999. Epidemiology of mango malformation in Guerrero, Mexico, with traditional and integrated management. Plant Dis. 83:223-228. The temporal progress of malformation (MM) of mango (Mangifera indica) was studied from 1993 to 1995 with three management technologies applied to commercial plantations in North Guerrero, Mexico. Management influenced shoot production and thus determined the dynamics of epidemics. Environmental factors also affected disease incidence, particularly through an apparent effect on inoculum dispersal. In general, integrated management (IM), consisting of pruning, acaricide, and fungicide sprays, resulted in slower rates of epidemic development, lower levels of initial and final disease, and lesser areas under the disease progress curves. In the first cycle, IM increased yield per tree by 51% in relation to high technology (HT) and 74% in relation to lower traditional technology (LT), representing a benefit-cost rate of 2.8 and 3.3, respectively. Change of malformation incidence was correlated positively with the number of macroconidia of Fusarium sp. trapped in the canopy ( r = 0.90, P = 0.0001) and wind speed (r = 0.83, P = 0.0001); both variables lagged over a 4-month period. The greatest change in malformation occurred during the main vegetative flush, which occurred 3 to 6 months after picking the fruit (May). The accumulated proportion of diseased shoots was correlated with the following variables measured over a 1-week period: average maximum daily temperature (r = ‐0.68, P = 0. 01), average temperature per hour ( r = ‐0.59, P = 0.04), average number of hours with relative humidity ≥60% (r = ‐0.82, P = 0.001), and wind speed (r = 0.94, P = 0.0001). In general, the greatest spore density was found during the rainy season, with a morning periodicity showing the highest correlation with wind speed ( r = 0.812, P = 0.0001). F. subglutinans was isolated consistently from diseased (86%) and asymptomatic (5%) vegetative and flowering shoots.

Nine epidemiological parameters, estimated to characterize each of 60 disease progress curves of papaya ringspot (papaya ringspot virus type P [PRSV-P]) incidence on papaya (Carica papaya), were analyzed using a combination of principal component and cluster analysis techniques to select the best subset of variables with the highest explanatory capacity and to classify epidemics according to their degree of similarity. The effects of cultural methods, transplanting date, planting density, and field location on epidemic classification and control of papaya ringspot also were examined. Standardized area under disease progress curve (AUDPC s ), shape parameter (c) of the Weibull distribution function, and time between transplant date and first symptoms (X 0 ) were selected, using principal component analysis, as the most important variables and represented 83.5% of the overall variance. The remaining variability was explained by the apparent infection rate (r G -Gompertz) standardized by the Richard's method, the scale parameter (b) of the Weibull distribution function, initial and final disease incidence, time to reach 50% incidence, and time of epidemic duration. Five epidemic categories were defined through a direct linkage of the principal component scores associated with AUDPC s , c, and X 0 , via cluster analysis. Experimental site and transplanting date had more influence on the definition of epidemic categories than did planting density. No category indicated complete suppression of papaya ringspot. Epidemics associated with early transplanting dates (February, April, and June) were in the category representing the smallest AUDPC s ( 25%-days day -1 ), the longest time to first symptoms (≥ 120 days), and low values of c (1 to 3). AUDPC s was more sensitive to experimental site than the other factors. Transplanting dates in February and June were suggested as additional alternatives to April and May transplanting dates practiced by growers, to delay the epidemic onset and to reduce the incidence of papaya ringspot of Central Veracruz, Mexico.

A model to predict incidence of papaya ringspot was developed and validated from 5 yr of field observations in central Veracruz, Mexico. The model was developed from 1 yr of data collected from papaya (Carica papaya) plantations in two different locations in Veracruz during 1985-1986. Incidence of papaya ringspot was evaluated every 15 days, and viral infection was confirmed by ELISA. Aphid vectors (Myzus persicae, Aphis gossypii, A. nerii, A. citricola, and Macrosiphum euphorbiae) of papaya ringspot virus were collected every 3 days from Moericke yellow pan traps placed at each location