Sensibilidad de seis especies de Trichoderma aisladas de suelos agroforestales de Santa Cruz, Islas Galapagos a fungicidas de diferente modo de acción.

Abstract

The study aimed to determine the sensitivity of six Trichoderma species isolated Islands to fungicides with different modes of action from agroforestry soils of Santa Cruz, Galapagos. The methodology consisted of a completely randomized design of six isolates for five doses of six fungicides with three repetitions by using the isolates of Trichoderma harzianum, Trichoderma lentiforme, Trichoderma breve, Trichoderma orientale, Trichoderma resei and Trichoderma andinense. They were used in potato dextrose agar culture medium, with the active complexes of copper sulfate, tebuconazole, azoxystrobin, methyl thiophanate, cyprodinil and boscalid, in doses of 0.1, 1, 10, 100, and 500 parts per million. The data on the mycelial growth of the Trichoderma isolates were collected every 24 hours, in millimeters in the equatorial and polar axes. The mycelial growth rate was calculated, then the lethal dose was estimated, the inhibition percentage and the range of sensitivity was determined in the sensitive, slightly resistant, moderately resistant, and resistant categories, using a sensitivity scale. Data were analyzed with the R program using exploratory analysis with box-and-whisker plots, summary measurements, and Tukey's test for separation of means. The mycelial growth rate showed evident differences between the active principles, the species that showed a high resistance and higher growth before the different active principles was Trichoderma resei, being compatible with the products of different fungal modes of action investigated, followed by Trichoderma harzianum that showed a similar behavior before the chemical-biological combination. The isolates will give better results in the comprehensive management of diseases. It is recommended to evaluate the study at the nursery level to corroborate the results.