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ARS Home » Research » Publications at this Location » Publication #88422
Title: APPLICATION PARAMETER EFFECTS ON EFFICACY OF A SEMIOCHEMICAL-BASED INSECTICIDE

Author
item Hoffmann, Wesley
item LINGREN, P. - TAMU
item Coppedge, James
item Kirk, Ivan

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Field trials were conducted in areas that had populations of Mexican and Western corn rootworm beetles. The purpose of these trials was to determine the influence of application equipment and parameters on the efficacy of a semiochemical-based insecticide. The insecticide tested uses 90-95 percent less toxicant than conventional insecticides. Two formulations of the product, which vary only in manufacturing process and not chemical composition, were tested. The application equipment was varied to produce three droplet sizes to determine if droplet size affected efficacy. Three levels of applied product (pounds of product per acre) and spray rate (spray volume in gallons per acre) were also tested to evaluate the effects on product efficacy. Beetle populations were monitored before and after treatment using emergence cages, sticky traps, whole plant counts, and catch pans. The efficacy of the product was measured in terms of percent reduction in beetle numbers from pretreatment levels. Based on the results from the various test, recommendations for applications were made.

Technical Abstract: Field trials were conducted in areas that had populations of Mexican and Western corn rootworm beetles. The purpose of these trials was to determine the influence of application equipment and parameters on the efficacy of a semiochemical-based insecticide. The application equipment and operational parameters were varied to produce three droplet sizes, three applied product rates (lb. of product/acre), and three spray rate (spray volume in gal/acre) to evaluate the effects on product efficacy. Two formulations of the product, which vary only in manufacturing process, were also evaluated. Beetle populations were monitored using emergence cages, sticky traps, cone traps, and whole plant counts. The efficacy of the product was measured in terms of percent reduction in beetle numbers from pretreatment levels. Large droplets (>800 um volume median diameter (VMD)) did not reduc cadult populations as effectively as small (300 um VMD) and medium (600 um VMD) size droplets. Spray rate (4.7-14.1 L/ha) did not affect the efficacy of the product. Product rates ranging from 0.28 to 0.56 kg/ha resulted in similar levels of control. From laboratory and field experience, it was suggested that applicators include a spray additive to the spray mixture to help improve the rainfastness of the insecticide. The timing of the application to the emergence and life cycle of the beetles must be matched in order to make the application an effective adult control measure. By greatly reducing the adult population before egg laying can take place, the chances of larval damage to next years crop can greatly be reduced.