The strawberry, Fragaria×ananassa Duchesne (Rosales: Rosaceae), is an important crop in Mexico. We evaluated the tolerance of three newly developed Mexican strawberry varieties (CP0615, CPLE-7, and CPJacona) to Tetranychus urticae Koch (Trombidiformes: Tetranychidae), the most important pest of strawberry. We evaluated the effect of three different initial mite densities on population growth, duration of each developmental stage and survival of T. urticae on the three strawberry varieties. We also compared the photosynthetic activity (Pn), sub-stomatal CO2 concentration (Ci), stomatal conductance (gs) and the area of leaf damaged in the three varieties. The largest final density of mites occurred on the variety CP0615, followed by the varieties CPLE-7 and CPJacona. There were no significant differences in the duration of T. urticae developmental stages amongst the varieties, except for larvae where the shortest duration was on variety CPLE-7. The proportion of eggs reaching the adult stage (survival) was significantly lower on the variety CPLE-7. The number and morphology of the trichomes did not play an important role in the outcomes, as they were similar in the three varieties. There were no significant differences in Pn, Ci, and gs values amongst the three varieties in the presence and absence of T. urticae. The area of leaf damaged in variety CPLE-7 was significantly smaller than for the other varieties. Based on these results, and with regard to spider mite tolerance, we believe that the variety CPLE-7 has the greatest potential for further development, and eventually, for use on a commercial scale in Mexico.

Blackberry (Rubus ulmifolius Scott) is an economically important crop in Mexico. Eriophyoidea mites are among the most important arthropod pests affecting production of this crop worldwide. Despite this, reports on species diversity of Eriophyoidea on blackberry in Mexico are scarce. We sampled six orchards from two municipalities in the state of Michoacan, the most important region for blackberry production. Sampling was carried out monthly between May and November 2018. Only one species of eriophyoid mite was found, Diptacus rubuscolum Trinidad, Duarte and Navia. We conducted a detailed morphological study of this mite and a complementary description is presented. In addition, we obtained partial sequences of the mitochondrial cytochrome oxidase subunit I (mt COI), the 18S and 28S of the rRNA. The duration of each developmental stage was determined under controlled conditions (25 °C, 60% RH and 12:12 light regime). We confirmed the identity of D. rubuscolum by comparing partial sequences of the D2 region within the 28S rRNA from our samples and sequences retrieved from GenBank. Overall, morphological characteristics were in line with the type specimens. However, some differences on body shape and empodium structure were pointed out. The developmental stages of D. rubuscolum were egg, larva, nymphochrysalis, nymph, imagochrysalis and adult, with a mean duration of 75 (±10), 56 (±9), 21 (±7), 41 (±8), 19 (±6) and 114 (±12) hours respectively. The information produced provides insight and knowledge on the occurrence of this species on blackberry in Mexico as well as on original biological aspects.

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