RESUMEN In order to determine the effect of infestations with Tuta ab soluta on the growth and development of tomato plants under greenhouse conditions, six densities of the pest were evaluated (0, 2, 4, 6, 8, and 10 females/plant). A completely random design with three replicates per treatment was employed. The percentage of leaf area and number of fruits damaged were estimated and those variables were used to construct a damage curve. The plants exposed at infestation levels between 6 and 10 females presented the highest percentages of leaf area consumed (between 27 and 43%), damage on fruits (between 45 and 100%), and loss of apical leaves in comparison with the treatments with two and four females/plants. The height, number of internodes, number of leaves and leaflets, number and biomass of fruits were differentially affected by the densi ties of T. absoluta infestation (P≤0.05). The leaf area and the biomass of stems and leaves did not vary with the infestation levels evaluated. On the damage curve, we observed that with more than two females per plant, the variables biomass, quality and number of fruits, result affected in an important way. Con el fin de determinar el efecto de infestaciones con Tuta absoluta sobre el crecimiento y desarrollo del tomate bajo invernadero, se construyo una curva de dano a partir de la evaluacion de seis densidades de la plaga (0, 2, 4, 6, 8 y 10 hembras/planta) empleando un diseno completamente al azar con tres repeticiones. Se estimo el porcentaje de area foliar y numero de frutos afectados y a partir de esta variable se genero la curva de dano. Las plantas sometidas a niveles de infestacion entre 6 y 10 hembras presentaron mayores porcentajes de area foliar consumida (entre 27 y 43%), dano en fruta (entre 45 y 100%) y perdida de hojas apicales en comparacion con los tratamientos con dos y cuatro hembras/planta. La altura, numero de entrenudos, numero de hojas, numero de foliolos, area foliar, biomasa total y biomasa de fruta fueron afectados diferencialmente por las densidades de infestacion de T. absoluta (P≤0,05). Por el contrario, las biomasas de tallos y hojas no fueron afectadas. En la curva de dano se observo que a partir de 2 hembras/planta se da un efecto negativo importante en el numero de frutos totales y fruto sano, pudiendo generarse perdidas importantes de produccion con densidades por encima de esta cantidad de hembras.