BULK BLENDING FIRE ANT BAITS WITH FERTILIZER; AN ECONOMIC ALTERNATIVE

BULK BLENDING FIRE ANT BAITS WITH FERTILIZER; AN ECONOMIC ALTERNATIVE H. D. Dorough 1 , V. E. Bertagnolli-Heller 2 , L. C. ‘Fudd’ Graham 3 and K.A. Ridley 4 Fire ants are a recurring problem in southern pastures. Effective and relatively inexpensive treatments are available for the management of these pests. But these applications are usually cost prohibitive due to low return per acre on capital investment for these fields. Escalating fuel prices have forced an increase in the cost of applying fire ant baits. Mixing baits with fertilizer could allow producers to apply these products in a bulk mix and minimize increased application costs. Two growth regulator fire ant baits, pyriproxyfen and s-methoprene, were mixed with fertilizer at the local farmer’s cooperative. A pyriproxyfen treatment, a fertilizer treatment and an untreated control were also included in the experiment. All treatments were applied to the pasture at label rates in a randomized complete block design replicated four times. Maximum control obtained in the study was 86%. There were no significant differences between the bulk mix treatments and the pyriproxyfen treatments at 5, 8, 14 or 21 weeks post-treatment. However, fire ant mound numbers declined slower in the bulk mix treatments than in the pyriproxyfen only treatment. Mound numbers were less than five per acre in all bait treatments 21 weeks post treatment. ABSTRACT INTRODUCTION Since their introduction in Mobile, AL in the early 1900’s imported fire ants (IFA) have become the scourge of the southland. In Talladega County, AL the primary IFA infestation is a hybrid of Solenopsis richteri and Solenopsis invicta. Oak Valley Farms in Talladega, AL is a purebred Angus cattle operation. A 2005 survey of pastures on the farm revealed an average of 236 mounds per acre. It is easy to assume that such a fire ant population could disrupt cattle grazing and cause problems during the calving season. Alabama’s Record drought in 2006 and 2007 coupled with record high fuel and fertilizer prices has brought about a change in livestock producer attitudes regarding forage performance and the economics of pasture management. Producers are seeking effective and economical methods for pest control and fertility management in an effort to maximize livestock grazing efficiency. METHODS Two fertilizer-bait blends, a pyriproxyfen only treatment, a fertilizer only treatment and an untreated control were applied to one acre plots in a randomized complete block design replicated four times. Plots were sorted by population size (number of mounds) and replicates were assigned from highest to lowest mound numbers to reduce variation. The treatments were then randomized within each replication (Fig. 1). Two growth regulator fire ant baits, pyriproxyfen (Esteem Ant Bait) and s-methoprene (Extinguish Professional Fire Ant Bait) were blended with bulk fertilizer material at a local farmers cooperative (Fig 2). The 17-17-17 fertilizer blend with bait was mixed for approximately 5 minutes to ensure even distribution of the bait products. The fertilizer-bait blend was then augered into 4-ton, pull-behind spreaders and transported to the field. The spreader was calibrated to apply approximately 355 pounds of fertilizer per acre. The application rate was 1.5 pounds per acre for all bait treatments. The fertilizer-bait blends were taken to the field and applied immediately after mixing (Fig 2). Due to high temperatures, applications were not started until four p.m. Treatments were rated using fire ant mound counts in a ¼-acre circle centered in each one acre plot. Figure 1: Field plot randomization at Oak Valley Farms Talladega, AL RESULTS and DISCUSSION A much needed rain event occurred a few weeks after the project began resulting in increased mound count variation within treatment five on 17 July. Although the mean number of mounds increased in the untreated control there was no difference in any of the treatments. However, on 7 Aug, fire ant populations declined significantly in the pyriproxyfen treatment compared to the untreated control. On 18 September, 7 November and 18 March, fire ant populations in the fertilizer+bait blend treatments were not significantly different from the pyriproxyfen-only treatment and were significantly different from the control. Maximum control of 92% was achieved with the pyriproxyfen+fertilizer blend treatment. These results suggest that the fertilizer-only treatment provided some control of fire ant populations, but this population remained relatively constant throughout the trial. Mound numbers in these plots did not increase, as in the control. However, they were not significantly different from mound numbers in the control except on 18 March. Figure 2: Mixing bait at the local farmers cooperative and spreading bait in plots in the cattle pasture

1 Regional Extension Agent, Alabama Cooperative Extension System, Piedmont Region, Talladega, AL 35160

2 Consumer Horticulture Extension Agent/Master Gardener Coordinator, Clemson University Extension Service, Columbia, SC 29229

3 Coordinator, Alabama Fire Ant Management Program, Auburn University, Auburn, AL 36849

4 Research Assistant, Auburn University, Auburn, AL 36849

403 Ex + Fert 405 Es 401 Fert 205 Ex + Fert 304 Es 204 Fert 305 Fert 404 Es + Fert 202 Es + Fert 302 Es + Fert 101 Ex + Fert 104 Es 303 Ex + Fert 103 Es + Fert 301 Control 402 Control 105 Fert 203 Control 201 Es 102 Control a a a a a a a ab b ab b ab b b