CORN INSECT PESTS AND PATHOGENIC DISEASES IN RELATIONSHIP TO SHATTERCANE POPULATIONS

The influence of shattercane, Sorghum bicolor L. (Moench), on the incidence of insects and pathogens of corn was studied in northern Tamaulipas, Mexico. Insects and pathogens studied included Helicoverpa zea (Boddie), Spodoptera frugiperda (J.E. Smith), Diatraea lineolata (Walker), Eoreuma loftini (Dyar), Phyllophaga crinita (Burmeister) Fusarium spp., Ustilago maydis (DC.) Cda., and Macrophomina phaseolina (Tassi) G. Goid. Except for P. crinita, all insects and pathogens occurred independently of shattercane. Populations of P. crinita increased with increasing shattercane densities, following a curvilinear response. This is probably a result of adults preferring shattercane over corn and/or denser vegetations.