Spatial Distribution of Nymphs Populations Bactericera cockerelli Sulc in Tomato Crops (Physalis ixocarpa Brot)

Tomato crops (Physalis ixocarpa Brot.) are produced in almost allMexico, part of the United States and Central America. Recently the tomatoproduction has suffered economic losses of 70% to 80% due the presence ofyellowing and floral abortion, whose causal agent has been attributed to thepresence of phytoplasma; an insect vector of these phytoplasma is Bactericeracockerrelli Sulc. Alternative control of this psyllid has lacked effectivenessbecause their spatial distribution is unknown within tomato plots. This studyaimed to determine the spatial distribution of populations of nymphs of B.cockerelli in four tomato plots, the determination of the spatial distribution wasperformed by means of geostatistics. The experimental semivariogram wasdetermined to adjust to a theoretical model (spherical, exponential or Gaussian)through the program Variowin 2.2, the adjustment was validated with the methodof cross-validation and aggregation maps of the pest were obtained throughKriging with Surfer 9.0 program. The short-term time-space stability of the pestwas determined through the tests Crámer-von Mises. The results showed thatpopulations of nymphs of B. cockerelli have a distribution of aggregate type,which was corroborated by density maps. Infestations are not present in 100% ofthe surface of the experimental plots, which helps to direct control measures onspecific areas of infestation.