|Reding, Michael - Mike|
Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2009
Publication Date: 12/18/2009
Citation: Wang, X., Zhu, H., Reding, M.E., Locke, J.C., Leland, J.E., Derksen, R.C., Spongberg, A.L., Krause, C.R. 2009. Delivery of Chemical and Microbial Pesticides from Drip Irrigation Emitters. Applied Engineering in Agriculture. 25(6):883-893.
Interpretive Summary: Physical properties of designated pest management agents, especially microbial products are quite variable. Specific evaluation of deliverability for these products applied through drip irrigation systems with flow characteristics is lacking. There are concerns whether they can be uniformly distributed throughout drip lines and within target areas. Experiments were conducted to investigate distribution uniformity and recovery rate of chemical and microbial control agents with different physical properties discharged from emitters at various flow capacities throughout drip lines. The pest management agents included a water soluble chemical used to track flow, a suspendible microbial bio-insecticide, a suspendible microbial bio-fungicide, and microbial entomopathogenic nematodes. Test results demonstrated that drip irrigation could be an alternative method to apply these products; however, their distribution uniformity and recovery rate throughout the drip line varied with the physical properties of the individual product formulation and emitter capacity. For nursery fields if a drip irrigation system is in the place, injection of these products into drip lines offers an alternative strategy for an efficient application of pesticides and reduces farmer’s capital investment. However, discharge rates of the microbial control agents must first be determined to compensate for their non-uniformity of delivery and low recovery rates from emitters.
Technical Abstract: Applying pesticides uniformly to the target area with drip irrigation systems is essential for achieving effectiveness of efficient insect or disease control and the sustainability of a safe environment. The uniformity and recovery rate of water soluble and insoluble materials of chemical and microbial pesticides with different physical properties discharged from emitters throughout drip lines was evaluated. The materials were a water soluble fluorescent tracer (BSF), a flowable water-dispersible insecticide (Imidacloprid), a suspendible microbial entomopathogenic fungus (EPF), a suspendible microbial soil fungicide (SF), and microbial entomopathogenic nematodes. Treatments also included three different sizes of emitters with flow capacities of 2.0, 4.2 and 6.9 L/h, respectively. Although all materials were readily deliverable through the drip irrigation system, the uniformity of the materials throughout the drip line varied with the material formulations and emitter flow capacity. For all emitter flow capacities, EPF had the highest coefficient of variation for discharge from emitters throughout the drip line, followed by SF, Imidacloprid, nematodes, and fluorescent tracer. Conversely, the uniformity of distribution and recovery rate of the five materials was in the reverse order. Emitter flow capacity affected the recovery rates of Imidacloprid and SF discharged from the emitters, but not of BSF, EPF and nematodes. Drip irrigation was demonstrated as a viable alternative for application of water soluble and insoluble materials. However, the discharge rates of EPF and SF must first be determined to compensate for their non-uniformity of delivery and low recovery rates from emitters.