Impact of trellis system on blackberry crop canopy architecture and microclimate with implications for pest management

M. Duncan, A. Lay-Walters, L. Herrera, A. McWhirt, A.J. Cato, R. Threlfall
Trellising systems alter crop canopies with potential implications on crop temperature and humidity, which can impact pest management. The rotating cross arm (RCA) trellis modifies the blackberry plant canopy to align floricanes into a single-plane compared to the dual plane canopy created by standard T- or V-trellises. Fewer spotted wing drosophila (SWD) (Drosophila suzukii) eggs in blackberries grown on the RCA have been attributed to differences in canopy microclimate. In May-July of 2021 and 2022, blackberry cane density, canopy temperature, canopy relative humidity (RH), and occurrences of SWD in blackberries grown on an RCA and T-Trellis were assessed at the University of Arkansas System Division of Agriculture Fruit Research Station in Clarksville, AR, USA. Sensors were placed at four locations (top, middle, bottom and inner or short arm to correspond to primocane location) in the canopy of each trellis to monitor canopy temperature and RH. Average lateral cane number plant‑1 were similar between the two trellis systems, but fewer and longer laterals m‑1 row were present on the RCA resulting in a less dense canopy due to the single plane trellis architecture. The top and middle of the T-trellis were generally warmer than those canopy locations in the RCA. Measured RH values were higher in the T-trellis at the top, middle, and bottom compared to the same locations in the RCA. This finding is important because SWD prefers higher humidity environments, and the canopy architecture of the RCA may reduce favorable SWD habitat in blackberry plants. Very low populations of SWD were present in both years of our study. In 2021, SWD eggs were only found on blackberries at the bottom of plants on the T-Trellis where the highest RH was recorded.
Duncan, M., Lay-Walters, A., Herrera, L., McWhirt, A., Cato, A.J. and Threlfall, R. (2024). Impact of trellis system on blackberry crop canopy architecture and microclimate with implications for pest management. Acta Hortic. 1388, 241-248
DOI: 10.17660/ActaHortic.2024.1388.36
RCA, T-trellis, humidity, temperature, SWD

Acta Horticulturae