Automated trichome counting in soybean using advanced image-processing techniques.

PREMISE: Trichomes are hair-like appendages extending from the plant epidermis. They serve many important biotic roles, including interference with herbivore movement. Characterizing the number, density, and distribution of trichomes can provide valuable insights on plant response to insect infestation and define the extent of plant defense capability. Automated trichome counting would speed up this research but poses several challenges, primarily because of the variability in coloration and the high occlusion of the trichomes. METHODS AND RESULTS: We developed a simplified method for image processing for automated and semi-automated trichome counting. We illustrate this process using 30 leaves from 10 genotypes of soybean (Glycine max) differing in trichome abundance. We explored various heuristic image-processing methods including thresholding and graph-based algorithms to facilitate trichome counting. Of the two automated and two semi-automated methods for trichome counting tested and with the help of regression analysis, the semi-automated manually annotated trichome intersection curve method performed best, with an accuracy of close to 90% compared with the manually counted data. CONCLUSIONS: We address trichome counting challenges including occlusion by combining image processing with human intervention to propose a semi-automated method for trichome quantification. This provides new opportunities for the rapid and automated identification and quantification of trichomes, which has applications in a wide variety of disciplines.

Tick development on sexually-active bull moose is more advanced compared to that of cow moose in the winter tick, Dermacentor albipictus.

We performed a complete survey of ticks on 100 cm2 skin samples collected from 30 moose (Alces alces) harvested in 2017 in central and northern Maine, U.S.A. The samples were collected from 15 bulls, 13 cows, and 2 calves in mid-October when moose are breeding and winter ticks (Dermacentor albipictus) quest for a host. We identified only winter ticks with 99.2% in a juvenile stage; 3 adult ticks were found. Unfed nymphs were most common on bulls, whereas most ticks were fed larvae on cows and calves. The mean total count on bull samples was 21 ±â€¯4.4 (range = 0-55) and higher than on cows (6 ±â€¯0.5; range = 2-8). Unlike previous surveys, tick abundance was lowest on calves. Tick abundance was independent of age or weight of adult moose. The higher abundance and more rapid development of winter ticks on adult bulls likely reflects the seasonal influence of increased movements and hormonal cycles associated with reproduction.