Location: Application Technology Research
2020 Annual Report
Objectives
The long-term objective of this research is to advance spray applications with coordinated intelligent-decision technologies and strategies that enhance pesticide application efficiency and environmental stewardship for efficacious and affordable control of pest insects, diseases and weeds.
Objective 1: Develop intelligent precision technologies to efficiently apply pesticides and bio-products for efficacious and sustainable control of pest insects and arthropods, diseases and weeds to protect horticultural, field and greenhouse crops.
Sub-objective 1.1: Develop a reliable and user-friendly intelligent spray-decision system as a retrofit for new and existing air-assisted sprayers to deliver pesticides and bio-products accurately, economically, and environmentally for field specialty crops.
Sub-objective 1.2: Develop greenhouse intelligent spray systems for real-time control of individual nozzle outputs to improve spray deposition quality and reduce waste of water and chemicals.
Objective 2: Develop coordinated application methodologies to reduce pesticide use, reduce crop protection costs, reduce chemical contaminations to the environment, and protect workers, livestock, natural resources and sensitive ecosystems.
Sub-objective 2.1: Improve spray droplet fading process to maximize coverage area after deposition on plants through coordinating spray parameters including droplet size, formulation physical properties, plant surface morphology, and ambient air conditions.
Sub-objective 2.2: Improve spray droplet retention and reduce runoff on plants through coordinating the influences of droplet size and velocity, travel speed, spray formulation physical properties, crop leaf surface morphology, and leaf surface orientation on dynamic impact, retention, rebound and spread process of spray droplets on plants.
Approach
A versatile intelligent spray control system and mounting kits will be developed as a retrofit to different types of tractor-driven sprayers to deliver pesticides and bio-products for different specialty crops. A microprocessor controlled premixing inline injection module will be developed and integrated into the versatile spray control system. Performance of these sprayers will be tested for their accuracy to manipulate spray deposition, spray drift, off-target loss and spray volume consumption in comparison with conventional sprayers. Efficacy tests will be conducted in nurseries, apple orchards and vineyards to compare pest control, pesticide quantity used, and cost savings for the sprayers with and without intelligent functions. Spray drift models will be developed to predict movement of droplets discharged from conventional and intelligent sprayers under nursery, orchard and vineyard conditions.
Greenhouse intelligent spray systems will be developed for real-time control of individual nozzle outputs to improve spray deposition quality and reduce waste of water and chemicals. The automatic greenhouse spray system will be a retrofit attached to existing watering booms. Laboratory tests will be conducted to validate the spray control system accuracies in spray delay time, nozzle activation and spray volume using artificial objects of different regular geometric shapes and surface textures, and artificial plants of different canopy structures. Spray deposition and pest control efficacy tests in greenhouses will then be conducted to validate the intelligent spray control system.
Microscopic spray droplet spreading times and areas on leaves will be investigated to maximize and stabilize coverage area after deposition on plants. Investigation parameters include droplet size, formulation physical properties, plant surface morphology, and ambient air conditions. Droplet fading rate, absorption rate and residual pattern coverage area will be measured on the waxy, semi-waxy and hairy leaf surfaces, and hydrophilic and hydrophobic glass slide surfaces. Field experiments will be conducted in ornamental nurseries, orchards, greenhouses, vegetables, traditional crops and weeds to verify laboratory discoveries effects of the most influenced factors on droplet spreading areas.
Dynamic effects of spray parameters on the droplet impact, rebound, retention, adhesion, and spread process on plants will be determined. The parameters are droplet size and velocity, travel speed, spray formulation type, and leaf surface morphology and orientation.
Significance of coordinating these parameters to improve spray droplet retention and reduce runoff on plants will be analyzed. Dynamic impact of water-based droplets on plant leaves will also be investigated in a wind tunnel under controlled conditions.
Progress Report
A new laser sensor was selected and evaluated for new intelligent spray control system modification. The new sensor was more durable and economic than the previous sensor. Droplet size distributions from modified variable-rate nozzles coupled with pulse width modulated solenoid valves were investigated to improve spray deposition quality for the greenhouse intelligent spray system development.
To provide evidences for growers to reliably use the intelligent spray technology, comparative tests of the ability to control insects and diseases with intelligent sprayers and the same sprayers with conventional constant-rate mode were conducted at one fruit farm and two ornamental nurseries in Ohio, at one nursery and one apple orchard in Tennessee, and at one nursery and a research fruit farm in Oregon during the growing season.
Field tests in a two-year old apple orchard in a research fruit farm in Ohio, were conducted with the intelligent spray control system attached to an air-blast orchard sprayer. Spray deposition distributions on multiple-row trees were quantitatively evaluated to determine if a single spray pass could provide adequate spray deposition and coverage on young apple trees in the first and downwind rows, in an effort to reduce production costs and reduce the number of spray passes required for effective pest control in young apple orchards. Spray deposition and coverage tests were also conducted to evaluate performance of the intelligent spray control system retrofitted on an air-assisted semi-tower sprayer in a vineyard in Australia.
A commercial version of the intelligent spray control system was developed with joint efforts between ARS and an industrial partner and a commercial product was released to the market by the cooperator.
Accomplishments
1. Update on intelligent spray system commercialization. A commercial version of an intelligent spray control system as a retrofit kit to existing sprayers was developed with joint efforts between ARS researchers at Wooster, Ohio, and engineers at a commercial partner. The commercial product was released to the marketplace. The commercial intelligent spray control product received 2020 American Society of Agricultural and Biological Engineers (ASABE) Davidson Prize, 2020 ASABE AE50 Award Winners, and 2020 World Ag Expo Top-10 New Product Winners. The availability of the commercial product enables growers and sprayer manufacturers to upgrade their existing sprayers without purchasing or redesigning new sprayers to achieve intelligent spray benefits of significant chemical savings and environmental protection.
Review Publications
Chen, L., Wallhead, M., Reding, M.E., Horst, L., Zhu, H. 2020. Control of insect pests and diseases in an Ohio fruit farm with a laser-guided intelligent sprayer. HortTechnology. 30(2):168-175. https://doi.org/10.21273/horttech04497-19.
Zhang, Z., Zhu, H., Guler, H. 2020. Quantitative analysis and correction of temperature effects on fluorescent tracer concentration measurement. Sustainability. 12(11):4501. https://doi.org/10.3390/su12114501.
Manandhar, A., Zhu, H., Oskan, E., Shah, A. 2020. Techno-economic impacts of using a laser-guided variable-rate spraying system to retrofit conventional constant-rate sprayers. Precision Agriculture. https://doi.org/10.1007/s11119-020-09712-8.
