A Simple, Inexpensive, Portable Apparatus for Injecting Experimental Chemicals in Drip Irrigation Systems

The loss of 1,2-dibromo-3-chloropropane (DBCP) as a postplant nematicide created a serious void in nematode protection for crops nationwide. An acceptable replacement for DBCP is needed, especially on susceptible perennials such as grapes, Vitis vinifera L. Phases of our postplant nematicide research were conducted in commercial vineyards where nematode disease existed on established vines watered by drip irrigation. Drip irrigation was chosen as a delivery system for nematicides because it is becoming a popular form of irrigation. Most vineyards are irrigated by a single 13-mm line placed on the soil surface under the vine row. One or two emitters deliver the water supply to each vine in the row. Sixty vines are often irrigated with a single line, and 16.2 hectares are often watered simultaneously with a single pump. A small mechanical injection machine was devised to test nonregisterd chemicals in small plots in commercial vineyards. This apparatus allowed injection of chemicals into a dripline at any location to treat 5 l0 vine plots with candidate nematicides. With many injectors, various replicated treatments may be applied simultaneously. Thus water ing di f ferences and o the r sources of experimental variation among treatments can be avoided. Data from such small plots are as reliable as data from larger plots. Fur thermore the chemical injector developed is inexpensive enough to be used for research purposes. The injector is simple, accurate, and easily deployed, enabling a researcher to in-