Incidencia del saltahojas verde de la ca？a en siete cultivares de ca？a de azúcar, Estado Táchira, Venezuela

the green leafhopper, saccharosydne saccharivora, is the most important pest in the sugarcane crop of san antonio-ure？a valley in táchira state, venezuela. it is able to affect plants under six months of age, inducing direct and indirect damage. lately, it was found that the insect is a vector for yellow leaf syndrome. consequently, a screening of the inia sugar cane collection at táchira state for its reaction to the insect was a critical goal to achieve. the collection is located at the experimental farm of the táchira sugar mill (cazta) at san antonio- ure？a valley and includes cultivars b 80-529, b 67-49, b 74-118, b 80- 549, v 75-6, b 81-494 and v 71-39, which were evaluated. experimental design was a random block with four repetitions and seven treatments. eight weekly evaluations of leafhopper populations were conducted on first ratoon three month old plants from february to april 2003 where a scale ranging from 0% (absence of insect) to 100% (the whole leaf cover by leafhoppers) was used. anova and tukey tests were conducted by infostat program. results indicated significant differences (p<0,05) between cultivars for weekly evaluations and total averages. b 80-529 and b 67-49 had the lowest mean incidence (10% and 25,46% respectively) while b 81-494 and v 71-39 resulted with the highest means (56,12% and 56,33%). the highest values for b 81-494 and v 71-39 (81,33% and 79,33%) occurred during the third and fourth week (18/ 03/2003) when the lowest rain and relative humidity levels were observed. these results suggest the existence of a biotic factor in b 80- 529 and b 67-49 which deters leafhopper development as well a negative effect of rain on insect population.