- Fruits: berries (strawberries)
- Education and Training: decision support system, demonstration, extension, focus group, on-farm/ranch research, workshop
- Pest Management: biological control, field monitoring/scouting, integrated pest management
Farmers are requesting in-depth testing of how UAS (Unmanned Aerial Systems) can be
integrated successfully into strawberry production to improve management practices. California
produces 88% of US strawberries, with an annual value of approximately $2.6 billion, and the
California Strawberry Commission identifies spider mite management a key research priority.
Little is known about the spatio-temporal dynamics of spider mites in strawberry, and
consequently, about the optimal timing to release predatory mites, their natural enemies. With
this study, a collaboration between scientists, extension experts, and commercial growers, we
will demonstrate that airborne remote sensing can be used to detect spider mite hotspots and
therefore pinpoint when and where predatory mite releases are needed. The three-year project
will lead to the following outcomes: 1) demonstrate relationships between spider mite presence
and abiotic stress, important indicators of outbreak risks; 2) a spatially optimized, reliable and
practically feasible manual sampling plan for spider mites in strawberry fields; 3) hyperspectral
airborne remote sensing-based characterization of spider mite hotspots to spatially optimize
releases of natural enemies. Deployment of novel, labor-extensive, and precise airborne remote
sensing technologies to monitor crop health and mitigate pest risks is highly compatible with
existing management practices. Educational outreach involves hands-on workshops and lectures
on spider mite sampling at grower and ag professional meetings throughout the California
strawberry growing region. Growers outside this area will be reached through publications in
trade journals and other grower media. Also, we will organize a panel discussion on the potential
of UAS in strawberry management and beyond. Both the educational outreach and research
outcomes are easily transferable to strawberry growing regions elsewhere, and could be
expanded to include monitoring for other pests and pathogens. This project will enhance efficacy
of biocontrol agents and reduce dependence on miticides, enhancing sustainability of spider mite
management practices in strawberry.
Project objectives from proposal:
Objective 1: Experimental characterization of the relationship between: 1) leaf micro- and
macro-element composition and leaf reflectance, and 2) spider mite-induced stress and leaf
reflectance in project years 1 (May – July 2017) and 2 (May – July 2018). Quantifiable outcome:
A research article describing a model of the factorial relationships between leaf micro- and
macro-element composition, leaf reflectance, and spider mite-induced stress. This objective will
start in May 2017 and will be completed in May 2019.
Objective 2: Characterization of the spatio-temporal distribution of spider mites and their natural
enemies in project years 1 (May – July 2017), 2 (May – July 2018), and 3 (May – June 2019).
Quantifiable outcomes: 1) spatio-temporal data sets from 120 combinations of commercial
strawberry field, sampling event, and growing season, 2) a research article describing a spatially
optimized sampling plan for spider mites in strawberry fields. This objective will start in May
2017 and will be completed in April 2020.
Objective 3: Hyperspectral airborne remote sensing-based characterization of hotspots with
emerging spider mite outbreaks in project years 1 (May – July 2017), 2 (May – July 2018), and 3
(May – June 2019). Quantifiable outcomes: 1) hyperspectral airborne remote sensing data sets
from 120 combinations of commercial strawberry field, sampling event, and growing season, 2)
a research article describing the use of hyperspectral airborne remote sensing to spatially
optimize releases of natural enemies to control spider mite outbreaks in strawberry fields. This
objective will start in May 2017 and will be completed in April 2020.
Objective 4: Participatory (hands-on) educational outreach on how to improve spider mite
sampling and interpretation of sampling data in project years 2 and 3. Quantifiable outcomes: 1)
dissemination of project results on spider mite sampling to a minimum of 300 growers, 2)
publication of project results on spider mite sampling on the UC IPM website (2). This objective
will start in May 2018 and will be completed in April 2020.
Objective 5: Panel discussion on the potential of UAS in strawberry management and beyond in
project year 3. Quantifiable outcomes: 1) we will organize a panel discussion with ca. 15
growers and ag professionals, 2) main discussion points from panel discussions will be
summarized in a white paper to be presented to the California Strawberry Commission and other
stakeholder organizations. This objective will start in October 2019 and will be completed in