Written by Ricardo Lima Pinto, Tianna DuPont, WSU Extension. January 2, 2024.
Washington State University is piloting a Scouting Network to provide pear growers with natural enemy and pest information. Scouting is an essential tool for integrated pest management (IPM), which integrates cultural and biological as well as insecticidal controls and employs monitoring and economic thresholds. After the first year of the pilot participants reported using scouting data to improving fruit quality and facilitating adoption of IPM.
What is the Scouting Network?
The goal of the Scouting Network is to provide pear growers with weekly pest and natural enemy information to support effective implementation of pear pest management. Participants receive weekly scouting information including psylla adults and natural enemies per beat tray; psylla nymphs, mites, and mealy bugs per leaf; and projected psylla populations. In 2023, the first season of the project, we developed a Washington State University database and mobile application (Figure 1). The scouting report is available by mobile app, e-mail, and text messages (Figure 2). A grant from the WSDA Specialty Crop Block grant is funding the 2023-24 pilot of the Scouting Network where we hope to develop a model and tool to provide information to growers adoption pear IPM throughout the state.
Why have a Scouting Network?
Intensive scouting of natural enemies as well as pests is critical in order to effectively apply new bio-based integrated pest management (bIPM) tools to improve fruit quality and reduce broad spectrum sprays. Growers and consultants asked us to develop new tools because standard psylla spray programs are costing $1000 to $1800 but not always providing consistent results (e.g. US#1 packouts from standard programs ranging from 62 to 99%)[1]. The IPM toolbox now has new tools: phenology timings, economic and natural enemy thresholds, products which conserve natural enemies and is providing similar fruit quality on average to standard programs[2]. However, more boots on the ground from scouts is critical to apply IPM. We, “Need a lot of eyes in the orchards to do IPM,” consultants explain. Scouting for IPM, which includes natural enemies, can take twice the time. “If I did not have this scouting data, I would only be able to do IPM on a few blocks,” another participating consultant explained. Scouting Network information on natural enemy populations can allow growers to avoid late season sprays when predator populations are high and psylla numbers are low. “We were able to stop spraying earlier when we saw natural enemies come in,” one participant explained.
How do we scout?
We use a standardized method of beat trays and leaf samples collected randomly in the orchard so numbers can be compared to thresholds. Scouts take 30 beat trays randomly zig-zagging along transects which cover the variation in the entire 10 to 20 acre pear block. Each tray consists of 3 firm taps with a stiff rubber hose on a 0.75 to 1.5 inch-diameter limb 3 to 6 feet off the ground over a 18-in square tray with white cloth. In summer scouts select 100 leaves per block (10 from each of 10 randomly selected trees) for leaf brush counts. We make sure to select 5 leaves from the lower canopy with 2 in the tree center and 3 in the middle of each of 2 scaffold limbs per tree. We use a telescopic pruner to collect 5 leaves from 2 shoots or clusters that are difficult to spray such as the upper canopy and the back side of limbs. Many samples (e.g. 30 trays) and sampling which targets both areas likely to have high psylla numbers (e.g. tree centers and tops), as well as across the tree, allow us to compare overall populations and compare to thresholds developed with the same methods.
What did growers and crop consultants find useful about the Scouting Network?
The Scouting Network is informing spray decisions resulting in reduced psylla, better fruit quality, and reduced spray costs. We surveyed the 12 growers and 8 consultants 2023 project participants using interviews and online surveys. Participant growers told us they are using the scouting information to inform their spray decisions (77%, 570 acres), improving spray timing and effectiveness (62%, 404 acres), improving fruit quality (50%, 356 acres), and facilitating adoption of IPM (54%, 340 acres). Consultants said they used Scouting Network information to inform spray decisions (88%, 1486 acres). In some cases, consultants were able to reduce late season spray recommendations by 2-3 sprays (50% on 1358 acres). Scouting is an essential tool for the IPM program. Participants told us, “Scouting data helped me know if IPM was working,” and, “Having the scouting network is a safety to feel comfortable using IPM.”
How can I join the network?
Let us know if you have plots that you would like to be scouted in the 2024 season. If you have staff that wants to be trained in how to scout, we can provide both training and access to the scouting network platform, which will send you weekly reports. Scouting Network data will be most useful for blocks transitioning to IPM which use selective materials and where you hope to see natural enemies. It can also be useful for problem blocks. Input from pilot participants is critical as we develop this new tool to make it as reliable and useful as we can.
Funding and acknowledgements
The scouting network project is funded by the Washington State Specialty Crop Block Grant. This work was supported by the participants farmers and managers: Dave Burnett, Rollin Smith, Glade Brosi, Evelyn Arnold, Erica Bland, Jon Torrence, Keith and Kathy Archibald, Wayne Reiman, Kevin Carney, Loren Baird, Mel Weythman, Jorge Zavola, Blaine Smith, Sam Parker, Matt McDevitt, Shawn Cox and field staff: Scott Cummings, Neil Johnson, Troy Davis (Chamberlin Ag.) Kevin Kenoyer, Randy Nelson, Keith Granger (Wilbur-Ellis) Chuck Weaver, Jake Carson (GS Long) and Chris Strohm (NWW).
Additional information
Pear psylla integrated pest management
References
DuPont, S. T. and C. J. Strohm (2020). “Integrated pest management programmes increase natural enemies of pear psylla in Central Washington pear orchards.” Journal of Applied Entomology 144(1-2): 109-122.
DuPont, S. T., Strohm, C., Kogan, C., Hilton, R., Nottingham, L., & Orpet, R. (2023). Pear psylla and natural enemy thresholds for successful integrated pest management in pears. Journal of Economic Entomology.
Nottingham, L. and E. H. Beers (2022). Improving pear pest management with integrated approaches. Wenatchee, WA, Washington State Tree Fruit Research Commission. Final Report.
Contacts
Ricardo Lima Pinto
WSU Extension
j.limapinto@wsu.edu
(509) 293-8793
Tianna DuPont
WSU Extension
tianna.dupont@wsu.edu
(509) 713-5346
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[1] Fruit graded for pear psylla honeydew damage in 2018 and 2019 (DuPont et al. 2021a).
[2]Fruit quality in IPM has been similar to standard on avg with $173 fewer costs (DuPont and Strohm 2020).
