Abstract

GIRALDO-VANEGAS, Humberto et al. Incidencia del saltahojas verde de la caña en siete cultivares de caña de azúcar, Estado Táchira, Venezuela. Agronomía Trop. [online]. 2005, vol.55, n.4, pp.553-567. ISSN 0002-192X.

The green leafhopper, Saccharosydne saccharivora, is the most important pest in the sugarcane crop of San Antonio-Ureña 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- Ureña 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.

Keywords : Saccharosydne saccharivora; Saccharum spp.; population levels; incidence; promissory varieties; sugarcane.

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