Potential areas for the establishment of citrus leprosis virus vectors, Brevipalpus spp., in Mexico

Citrus leprosis is a viral disease vectored by the mites Brevipalpus californicus and Brevipalpus yothersi. This work aimed to determine the potential areas for establishment of both mites and viruses in Mexico, based on the geographical distribution of the hosts and the climatic suitability for the vectors. Life tables of both mites were constructed to determine their thermal requirements-base temperature and degree-days required to complete life cycle-and population growth parameters-net reproduction rate, generation time, and intrinsic growth rate. For this, the mites were confined in Citrus aurantium fruits at 20, 22.5, 25 or 30 degrees C, 60 +/- 5% RH and L14:D10 h photoperiod. Maps were generated where the climatic suitability for establishment of the mites and the citrus leprosis viruses was estimated in citrus-producing municipalities. The climatic suitability was determined through historical temperature records to calculate the potential number of generations per year, and ecological niche modeling based on collecting localities and bioclimatic variables using the algorithm Maxent. The base temperature was 9.5 degrees C for B. californicus and 10.2 degrees C for B. yothersi; degree-days required to reach adulthood were 372.1 and 331.7 degrees C, respectively. Potential sites for establishment of B. yothersi are mostly lowlands, whereas for B. californicus they are both lowlands and highlands. Temperature data indicate that B. californicus has fewer sites where it can develop > 16 generations per year than B. yothersi. According to our results, the sites where citrus leprosis is most likely to present high incidence are the sweet orange cultivars bordering the Gulf of Mexico.

Automated summary

This study aimed to determine potential areas for establishment of Brevipalpus californicus and Brevipalpus yothersi mites and citrus leprosis viruses in Mexico by constructing life tables and calculating thermal requirements, as well as using ecological niche modeling based on historical temperature records. The results indicated specific locations, such as sweet orange cultivars bordering the Gulf of Mexico, where citrus leprosis is likely to exhibit high incidence rates. Temperature data also showed differences in the number of generations per year that each mite species can develop, with B. californicus having fewer suitable sites than B. yothersi.