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United States Department of Agriculture

Agricultural Research Service

Research Project: CROP PROTECTION AND PRODUCTION STRATEGIES FOR HORTICULTURAL CROPS

Location: Application Technology Research Unit

2012 Annual Report


1a.Objectives (from AD-416):
The objective of this project is to enhance food and ornamental production through improved means for delivering agrochemicals such that utilization of the materials is maximized while losses from leaching, drift, or off-target loss are minimized. These methods will provide abundant, safe food and ornamental crops. These discoveries will minimize environmental impact, reduce production costs, and reduce worker exposure. The specific objectives for the next five years include: Objective 1: Develop new or enhanced delivery technologies that provide the most efficacious application of production materials, including nutrients and pest management materials. Sub-objectives: Identify application factors affecting distribution and quality of deposits of pest management materials applied to nursery, floricultural, vegetable, fruit, and field crops, and to integrate findings with Drift Reduction Technology (DRT) research into crop production programs. Develop automated or mechanized chemical delivery technologies for greenhouse production systems based on pest population information and/or plant development and plant stress information. Objective 2: Improve understanding of substrate chemical, physical, and biological properties to improve container crop production while minimizing agrichemical leaching. Sub-objectives: Evaluate the use of regional agricultural/forest byproducts and synthetic materials for use as a substrate in nursery containers. Determine the effects of irrigation parameters and hydraulic properties of soilless substrates on nutrient and pesticide leaching from pot-in-pot production systems.


1b.Approach (from AD-416):
Application systems will be evaluated by examining deposition patterns on artificial targets and plant tissue, atomization characteristics, and off-target spray movement on passive ground and airborne collectors. The effect of air and travel speed and their interaction with droplet size on deposition patterns on artificial targets placed within different field crop canopies will be examined in field trials. Full assessment of the potential benefits of any DRT will be measured in the field under varying canopy conditions. The effect of air speed and its interaction with droplet size on deposition patterns on artificial targets placed within different field crop with horizontal and vertical target surfaces will be examined in field trials. Droplet size distributions and droplet velocities from atomizers will be determined using a particle/droplet laser image analysis system. Granular delivery systems will be evaluated for their ability to apply herbicides to potted surfaces. Pneumatic and mechanical means for aiding in movement through canopies will be incorporated into the delivery systems. The effectiveness of the delivery systems will be evaluated by examining the deposition granule patterns on the target surface as well as measurement of the amount of active ingredient. To improve safety, reduce production costs, and to put spray only where needed, a carrier system will be evaluated to automate spray delivery in greenhouse and sheltered environments. First studies will utilize a wheeled, hand-cart to evaluate technology to target spray delivery. Air-assist and electrostatic technology appropriate to a greenhouse production system will be evaluated. One or more synthetic materials and one or more agricultural materials will be compared with conventional pine bark for production of nursery plants. Polyethylene terephthalate (PET) is a synthetic material currently used for many applications that has potential as a substrate component. Another strategy will be to grow the substrate. Agricultural crops which produce large amounts of biomass will be grown, harvested, and processed into a substrate. PET, switchgrass chips and willow chips will be the first candidates tested for suitability as substrates. To determine the effects of irrigation parameters and hydraulic properties of soilless substrates on nutrient and pesticide leaching from pot-in-pot production systems a commercial pot-in-pot (PIP) system will be used. Pine bark will be amended with peat at three rates and irrigation will be applied either with a timer or automatically activated according to soil moisture readings from a neutron probe irrigation sensor. A complete fertilizer package and an insecticide will be incorporated into the substrate during the mixing process. A preemergence herbicide will be applied to the substrate surface of all containers after they are filled and planted. All production inputs and all climactic inputs will be recorded by data loggers. Leachates will be collected weekly and analyzed for all macro- and micro-nutrients using ICP analysis; insecticide and herbicide concentration in the leachates and plant tissue will be quantified with GC-MS analysis.


3.Progress Report:
Air-assisted and electrostatically charged sprays are being used to apply protectant materials to manage bacterial diseases. Spray deposits on adaxial and abaxial leaf surfaces will be measured to compare sprayer performance and deposits on maturing tomato fruit. Field scouting will be conducted during the season to evaluate the severity of foliar and fruit infection. Harvest samples will be taken from each test plot to compare differences in marketable yield between sprayer treatments. The results of this work will demonstrate if these new application technologies will provide better control of bacterial diseases than traditional, high volume, non-air-assist spray applications. Previous research conducted revealed that as much as 95% of herbicide spray applied to a potted ornamental canopy remains in the ornamental canopy and thus is not available to provide weed control. An air-assist granular spreader is being used to demonstrate the effectiveness of applications of granular preemergent herbicides to potted ornamental plants. Herbicide deposits are being measured around the pot under the canopy of a commercial variety of butterfly bush. Weed control following application is being monitored to determine the influence that canopy size has on the efficacy of the application. Nitrogen (N), phosphorus (P), and potassium (K) release was measured from controlled release fertilizers. Our goal is to develop models to predict release of N, P, and K as a function of ambient air temperature that can be accessed either from on-nursery meteorological equipment or from published temperatures on numerous internet sites. By accurately modeling N, P, and K release from these fertilizers, growers will be able to more accurately time follow-up fertilizer applications and thus provide nutrients more efficiently. Initial retention and release of N, P, and K was determined by repeated leaching of soilless growing media, amended with biochar, in laboratory columns over time. Nursery-scale studies have been initiated using the findings of the greenhouse trials in which two additional variables are being addressed; the addition of additional micro-elements and cultural practice modification to reduce leaching of the highly-soluble P. Our current focus is to develop production methods that limit P leaching so that crops can be grown without the use of additional P fertilizers. Research was initiated to develop a system by which a saucer is placed beneath nursery containers to serve as a water reservoir and prevent runoff of effluent. Effluent from nursery containers often contain high concentrations of N and P, which can be damaging to surface and ground water bodies. Our research is determining how individual container reservoirs, in the form of a simple saucer, can be used to prevent effluent runoff, reduce fertilizer usage (because none will be lost in effluent), and reduce water usage. We are currently growing three crops in this system, compared to traditional container production, to determine which variables (fertilizer rate, irrigation rate, substrate physical properties) should or can be altered to maximize plant growth.


4.Accomplishments
1. Uptake and effectiveness of systemic insecticides as influenced by application technique. ARS researchers at Wooster, OH conducted greenhouse studies to understand how application technique influences the movement of insecticides through the plant and biological efficacy. Thiamethoxam or Imidacloprid treatments included a drench application directly to pots containing a Zinnia plant or a foliar application to a single Zinnia leaf approximately half way up the plant stem. Drench treatments reduced aphid populations at all sampling locations while the foliar application only reduced aphid populations at the single leaf treatment site. Thiamethoxam appeared to move more quickly though the plant tissue than Imidacloprid. These findings demonstrate to producers how to improve plant quality for consumers and decrease pesticide use.

2. Pesticide deposition optimized for orientation of plant target areas. ARS researchers at Wooster, OH initiated field studies to understand how to most efficiently apply protective pesticides to plant targets with vertical and horizontal orientations. Because diseases or insect pests may occur on different parts of the plant canopy, it is important to understand how to best apply pesticides to different parts of the canopy. Field tests were initiated to evaluate effect that air-assistance, droplet size, and spray orientation had on deposits on targets having mostly horizontal or vertical orientation using wheat as a test plant. Over the range of application parameters evaluated, flatter orientation of the spray relative to horizontal helped produce higher deposits on vertical plant sections. Vertical spray delivery was better at treating horizontal targets. Air-assist was not effective at increasing deposits on the plant sections which were considered low density. Producers can use these findings to adjust their equipment for precision application to parts of the plant canopy that require protection and to reduce spray drift.


Review Publications
Ozkan, H.E., Paul, P.A., Derksen, R.C., Zhu, H. 2012. Influence of application equipment on deposition of spray droplets in wheat canopy. International Advances in Pesticide Applications --Aspects of Applied Biology. 114:317-324.

Derksen, R.C., Canas, L.A., Ranger, C.M., Reding, M.E., Ozkan, H.E. 2012. Implications for pesticide delivery and insecticide selection using chemical analysis of plant tissue and efficacy. International Advances in Pesticide Application --Aspects of Applied Biology. 114: 279-286.

Derksen, R.C., Altland, J.E., Rennecker, J.C. 2012. Fate of pre-emergence herbicide applications sprayed through containerized hydrangia canopies. Journal of Environmental Horticulture. 30(2):76-82.

Derksen, R.C., Paul, P., Ozkan, H.E., Zhu, H. 2012. Field evaluations of application techniques for fungicide spray deposition on wheat and artificial targets. Applied Engineering in Agriculture. 28(3): 325-331.

Altland, J.E. 2011. Influence of pumice and plant roots on substrate physical properties over time. HortTechnology. 21:554-557.

Last Modified: 7/24/2014
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