Tag Archives: pest management

Pest Management: Intelligent Sprayer system automatically adjusts to seasonal growth saving thousands of dollars per year

Lloyd Nackley

Highlights

  • Airblast sprayers should be calibrated throughout the growing season to maximize application efficiency.
  • The LiDAR guided Intelligent Sprayer system automatically adjusts to crop canopy sizes.
  • Compared to standard Airblast sprayers, the Intelligent Sprayer system can reduce pesticide volumes by more than 50% while achieving adequate coverage, reducing drift by > 33%.

Our research revealed  that the majority of directed canopy spraying of specialty crops (defined here as fruits, nuts, and horticultural crops) relies on the radial air blast sprayers. There are many reasons for the continued popularity of air blast sprayers such as customizable sizes, easily available parts for repairs, and robust construction using materials such as stainless steel that provide years of low maintenance use. Although the air blast sprayer continues to be an important and effective tool for the specialty crop industry, its widespread use has not been without issues.

When radial air blast sprayers were first popularized in the 1950s, standard production practices favored hand labor, tree varieties popular at the time were around 6 m tall at maturity, and vines had large dense canopies. Modern plant breeding and horticultural practices, such as pruning and training systems, have revolutionized specialty crop production leading to higher density production systems designed for mechanization. Modern horticulture favors smaller trees (1–4 m tall) that are more productive per unit area than their historical counterparts, and pruning and trellis systems that create more open canopies. Despite the physical transformation of specialty crop production systems, the design of radial air blast sprayers has stayed largely the same. Consequently, unmodified radial air blast sprayers emit air and pesticide volumes that are often much greater than needed in modern high-density, open canopy systems.

Air blast sprayers from their early years to current day. (A) ‘Speed Sprayer’ on the Brown Fruit Farm near Worthington, OH, USA, 1947 (image courtesy of worthingtonmemory.org). (B) Air blast sprayer being used in research trials at the Ohio Agricultural Research and Development Center, Wooster, OH, USA, 1966. (C) Air blast sprayer at Rears Manufacturing in Coburg, OR, USA, 2018 From our publication.

Optimizing spray applications is necessary to address increasing pesticide expenses, limited labor availability, stricter regulations, and increased public awareness of pesticide use. For four years the Nackley Lab and Dr. Jay Pscheidt at OSU  have been collaborating with USDA-ARS, and the Fulcher group at the University of Tennessee to investigate application of a sensor-guided sprayer in horticultural systems. Sensor-based systems can apply a variable-rate spray that adapts to the changing canopy volume and density thereby reducing waste and off-target deposition compared with standard constant-rate sprayers.

Water sensitive spray cards are used to measure the coverage from applications by standard and sensor-based Airblast sprayers.

We tested the effect of variable- and constant-rate spray applications and phenological stage on spray volume, coverage, and deposit density in two perennial specialty crop systems: an apple orchard and a grape vineyard. Our research showed that the greatest differences in the volume of pesticide application between constant- and variable-rate sprayer modes occurred early in the season when the canopy was sparse. The standard spray mode discharged a constant volume regardless of the canopy characteristics causing pesticide spray to drift through the open canopies beyond the desired target. Reducing nontarget deposition is critical because aerial drift, ground spray, and runoff can contaminate surface and groundwater and have toxic effects on nontarget species. Unlike the standard spray mode, the Intelligent sprayer mode made real-time adjustments, decreasing the application volume when vegetation was absent, which resulted in a more targeted spray and decreased drift and off-target ground spray. Increasing spray efficiency is critically important because spray losses to the ground and aerial drift by constant-rate, air-assist sprayers can be 40% to 60% of total applied spray in orchards and 10% to 50% the total applied spray volume in vineyards.

Intelligent sprayer system in a red maple nursery.  https://agsci.oregonstate.edu/nursery/precision-spray-applications

If disease and arthropod control are not diminished, reducing the pesticide volume applied on a farm has multifaceted benefits. The most direct benefit, and usually the one that motivates the adoption of variable-rate systems, comes from a reduction in pesticide costs due to lower application volumes. Other research found variable-rate technology can reduce pesticide costs by as much as 67%. Reducing the amount of active ingredient per application also causes a concomitant decrease in environmental impact and worker exposure. Moreover, when the quantity of pesticide required to treat an area is decreased, additional efficiencies are realized from the reduced need to refill, such as lower fuel and labor costs, and improved ability to complete applications in windows of good weather. Additionally, requiring less water as in the case of lower spray volumes is beneficial for orchards and vineyards that have limited access to water.

More info:

Warneke, B.W., J. Pscheidt, and L.L. Nackley. 2021. How to do regular maintenance on air blast sprayers to ensure proper care for specialty crops. https://catalog.extension.oregonstate.edu/em9316

Warneke, B.W., J Pscheidt, R. Rosetta, and L.L. Nackley. 2019. Sensor Sprayers for Specialty Crop Production https://catalog.extension.oregonstate.edu/pnw727

Nackley L.L., B.W. Warneke, L. Fessler, J. Pscheidt, D. Lockwood, W.C. Wright, X Sun, and A. Fulcher. 2021. Variable-rate spray technology optimizes pesticide application by adjusting for seasonal shifts in deciduous perennial crops. HortTechnology 31 https://doi.org/10.21273/HORTTECH04794-21

Warneke,B.W., H. Zhu, J. Pscheidt, and L.L. Nackley. 2020 Canopy spray application technology in specialty crops: a slowly evolving landscape. Pest Manag Sci 77: 2157–2164

Pest Management: The Enemy of My Enemy

Melissa Scherr

There is an often-referenced but under-implemented army of spineless mercenaries wandering our nurseries in search of glory and fame.

Ok, that might be a bit melodramatic, but it’s not necessarily untrue. Natural enemies – that is, the natural enemies of PEST insects – are a naturally occurring force for good in production systems, feeding on every stage of many of our most economically important pests. Just as the pest insects invade when we supply an abundance of leafy hosts, the natural enemies of those pests respond to the abundance of prey. However, waiting and hoping these beneficial insects appear in sufficient numbers to manage a pest outbreak doesn’t always seem like a safe bet, which is why methods for enhancing the efficacy of natural enemies have become a staple in Integrated pest management strategies.

Utilizing natural enemies in crops has become increasingly popular as more species are available for mass releases from commercial suppliers – everything from the predatory mites that feed on the eggs and young of soft-bodied insects and other mites, to the above-pictured green lacewing, the juveniles of which not only appear as a tiny alligator, but feed just as voraciously (image right).

photo: juvenile lacewing feeding on a caterpillar;
cr. Ralph Berry, OSU Entomology

Understanding both the pest and the natural enemies in your system is key to utilizing the natural enemies as a pest management resources. It’s important to target all stages of the pest insect, which means identify the natural enemies that attack the different stages and encouraging the natural enemy populations at the right time. There are three main strategies for encouraging natural enemies:

  1. Conservation. Conserving the natural enemies that already exist in the production zone includes providing habitat and alternate food resources, so that when they prey numbers decline, the natural enemies don’t leave the area. This could mean providing debris for overwintering or alternate host plants that will not only attract pest *away* from crops but give predators a continual food resource.
  2. Augmentation. Once you’ve identified the natural enemies in your system, you can temporarily boost the population size by augmenting with commercially available NEs to create more pressure on the pest population. This can be used to target adults during mating season to limit reproductive success, or used to target egg and juvenile stages to limit damage later in the season. Understanding pest biology will help make decisions on how and when to use this strategy. Combined with conservation strategies, this can provide long term suppression, potentially lasting more than a single season.
  3. Inundation. This strategy is similar to augmentation but is usually implemented in artificial settings, such as greenhouses, when natural enemy populations are usually low or non-existent. Introducing a natural enemy at a high density to control a pest population can provide rapid suppression, though in this strategy, it usually is less reasonable to expect the natural enemies to remain once pest numbers are low. This is usually implemented with the expectation that natural enemies will need to be reintroduced as need.

Of these strategies, augmentation is the most ideal place to start – harnessing the natural enemies already occurring in your production zone. In 2021, the Nackley Lab released the pocket guide to Common Natural Enemies in Nursery Crops and Garden Pests (image right, click to download) to aid in identification and to help with decision-making when it comes to using natural enemies in pest management strategies. With color images showing distinguishing characteristics, commonly mistaken species and information on scouting for these natural enemies, it can help you get started with natural enemies in your crop.

common natural enemies cover
Common Natural Enemies cover, publication EC 1613

Pest Management: Springtime, the calm before the grape growing season storm

By Brent Warneke

In early spring in western Oregon many orchard crops are breaking bud, bulbs are showing off in gardens and perennials are bursting into spring glory. Wine grapes, however, are late to break bud, with average dates at our research vineyard in Corvallis of about mid-April each year. The month period between mid-March to mid-April is a good time to check off a number of tasks before vines break bud and attention needs to turn to managing vine growth.

Controlling weeds is easiest to do when everything is growing slower such as in winter and early spring.

When the grapes start dripping, bud break is around the corner.

If there are any weeds below vines that have established over winter, control these with herbicides such as glufosinate, glyphosate, or paraquat. After existing weeds have been managed, applying a pre-emergent herbicide helps prevent future weeds from establishing by creating a protective layer of herbicide in the soil. Products such as Casoron and Goal work well, with Casoron being a granule and Goal being a liquid product. For some pre-emergent herbicides, precipitation is needed after application to wash the product into the soil for maximum efficacy. Always carefully read the product label before making an application of any pesticide.

Control establishing weeds then apply a pre-emergent to prevent further weed establishment.

Before vines get growing is a great time to go through the vineyard and remove or destroy vines with galls or cankers. Look for growths such as crown gall at the base of vines or open cuts on cordons or vine trunks. Crown gall can girdle vines, starving the vine of nutrients and water, and is particularly harmful to young vines. Vines infected with crown gall or with open cankers should be removed and burned or transported away from the site and destroyed. Care should be taken when removing vines with crown gall as it can be spread on tools.

Prevention of trunk diseases is key to vineyard longevity, and extended wet periods in spring are perfect conditions for trunk disease pathogens to establish. The pathogens that cause trunk diseases release spores during extended wet periods, and spores are then spread by rain and wind to open pruning cuts. Consider applying protective fungicide applications to cover recently opened pruning wounds to prevent infection. A chemical free way to prevent infection by these pathogens is called double or delayed pruning. A pruning cut is made to vines leaving longer stubs than needed. Later in the season when rains have stopped a second cut is made to the desired length to allow the vines to heal without rain and thus decreasing the chance of infection by trunk pathogens.

Once the grapes get growing it’s hard to keep up so inventory pesticides, PPE and other inputs and place orders for anything that is needed. Calibrate your sprayer, make sure your tractor is functioning well, and order any extra parts that might be needed for the season. A little preparation goes a long way in a successful season, best of luck to all in 2022!

Left: Crown gall makes disorganized, bumpy growths typically located at the base of vines. Remove all affected vines (including as much roots as possible) and destroy, while trying not to contaminate other adjacent vines. Decontaminate tools with 10% bleach or 70% ethanol.