1. Rodent Management for Surface Drip Irrigation in Peanut Ronald Sorensen, Russell Nuti*, and Marshall Lamb USDA-ARS/National Peanut Research Laboratory; 1011 Forrester Dr., SE; Dawson, GA 39842 Mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. Surface drip (SD) irrigation of field crops in the Southeastern United States has been gaining interest (Figure 1). However, rodent damage from Hisbid cotton rat (Sigmodon hispidus), house mouse (Mus musculus), and Eastern harvest mouse, (Reithrodontomys humulis) is one of the major obstacles for SD success. Rodent damage of SD tubing in cotton (Gossypium hirsutum) and corn (Zea mays) is manageable, but peanut (Arachis hypogaea) has a much more dense and low growing canopy, which is more favorable for rodent habitat. Previous experiments show 25 times more rodent damage to SD tubing in peanut compared with cotton and corn. A single hole from rodent damage causes significant pressure loss and may affect a whole SD irrigation line (Figures 3-6). No methods to protect SD tubing from rodent damage have been developed for peanut. This research documents the effectiveness of several rodent management tools for SD in peanut. Introduction Special acknowledgement is given to Ernest Yoder for technical input and daily responsibilities involved with completing this research. Identify a cost effective means to protect drip tubing from rodent damage Compare repellant, insecticide, and rodenticide chemicals Untreated Lannate ® (methomyl) 12.5 ml/L @ 25 L/ha Ropel ® (benzyidlethyl) 50 % v/v @ 25 L/ha Orthene ® (acephate) 24 g/L @ 25 L/ha Contrac Blox ® (bromadiolone) 185 units/ha Evaluate thickness of drip tubing material for leak resistance and longevity 0.20 mm, 0.25 mm, 0.38 mm Objectives and Treatments Figure 5. Typical rodent damage on edge or fold of drip tubing. Clean tilled – cultivar ‘Georgia green’ – 0.9 m rows – SD tubing spacing 1.8 m Planted 05 May; Harvested 25 September 2005 Weed/disease control was according to accepted BMP by Univ. of GA Tubing was installed before crop emergence (Figure 2) Chemical treatments banded over tubing prior to canopy closure 5 treatments, 3 tubing thicknesses, 4 field positions, 3 replications = 180 plots (Figure 7) Irrigation was determined at 80% of IrrigatorPro recommendations for Peanut Tubing evaluated visually prior to harvest in 40’ (15 m) lengths by position (Figure 5) Peanuts harvested using conventional two-row equipment RCBD; ANOVA by Statistix 8 at P<0.05 Materials and Methods Chemical treatments did not deter rodent damage to SD tubing (Table 1) Thicker tubing received 3 times the damage of thinner tubing (Table 2) Regardless of tubing thickness, damage was so extensive that it was more economical to replace than to repair the tubing Results Drip tubing laid on the soil surface has no protection from rodent damage Chemical treatment banded over SD tubing adds no protection Thicker tubing was more attractive to rodents, and received 3 times the damage of thinner tubing Is rodent behavior linked to the typical Goldielocks Syndrome? Conclusions A light covering of soil/crop debris over SD tubing provides acceptable protection Minimal rodent damage on SD tubing has been documented in cotton and corn Rodent damage to SD tubing in peanut increased near grass borders Conversely, rodent damage was reduced in plots with clean tilled borders Observations From Other Experiments 2630 B1880 AB800 AHoles/ha 0.38 mm0.25 mm0.20 mmTube Thickness Table 2. Rodent damage of SD tubing with different wall thickness. 2370 A Lannate 1980 A Ropel 1370 A Orthene 1500 A1650 AHoles/ha C. BloxChemical Table 1. Rodent damage of SD tubing with various treatments. Untreated Irrigated Non -Irrigated Figure 1. Supplemental irrigation is important for peanut in the Southeast. Rep 3Rep 2Rep 1 Figure 7. Position 4 Position 3 Position 2 Position 1 C. BloxOrtheneRopelLannateUntreated 0.38 mm0.25 mm0.20 mm Field Layout and Experimental Design Chemical Treatments Tubing Thickness Fig 4. Fig 3. Figure 3. Drip tubing with emitter (~1.5 mm). Figure 4. Pressurized drip tubing with water exiting the emitter. Figure 2. Surface drip tubing installation. Figure 6. Severe rodent damage. 12 mm