Ciencias Agropecuarias

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Author: search.filters.author.Lema Chicaiza, Ana GabrielaSubject: search.filters.subject.FRESA (Fragaria x ananassa)

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    Antibiosis y antixenosis en dos cultivares de fresa (Fragaria x ananassa) variedades festival y san andreas al ataque de (Tetranychus urticae Koch)
    (2018) Lema Chicaiza, Ana Gabriela; Vásquez Freytez, Carlos
    The two-spotted spider mite, Tetranychus urticae Koch, is considered to be the main pest to strawberry crops worldwide. Studies on life history parameters of phytophagous species are useful tools for evaluating resistance or susceptibility of host plants to pests, including different cultivars of the same variety. Developmental time and reproductive parameters of T. urticae were evaluated on two strawberry cultivars (‘Festival’ and ‘San Andreas’) under experimental conditions (18.0 ± 1.0 ºC, 55.0 ± 10 % RH and 12:12 photoperiod). Total developmental time (adult-egg) showed to be shorter when mite was reared on strawberry leaf disks from cultivar ‘Festival’; being 16.3% faster than in ‘San Andreas’, although higher sex ratio was observed on the latter. Similarly, longevity, oviposition and post-oviposition periods in T. urticae females were significantly higher on ‘San Andreas’, being 22.14, 18.2 and 14.8% higher as compared to ‘Festival’. Conversely, no cultivar effect on daily oviposition rate or total number of eggs/female was detected. Based on the biological parameters of T. urticae on strawberry cultivars used in Ecuador, the cultivar San Andreas seems to show greater susceptibility to feeding damages inflicted by this species of mite, however, these results should be validated with field studies to determine the impact of feeding on the productivity of this strawberry variety. In the San Andreas variety, it was observed that the number of mites was higher in all strata of the plant compared to 'Festival'. Additionally, in leaves of the middle and upper strata the number of mites was similar, ranging from 0.2 to 3.6 mites / leaf and 0.6 to 3.0 mites / leaf in the upper and middle strata of plants located at 23 cm, while in plants with greater distance (33 cm) populations varied from 0.4 to 2.4 and 0.2 and 1.8 mites / leaf in the upper and middle strata.