Forrest County Mississippi Test of Apogee on Peanuts - 100 days after planting.
Fifty percent rate of Apogee 3.63 ounces per acre
fact, the PGR increased yields on all ten of the varieties Monfort tested at Expo. “It is a $60 treatment with two applications at the full rate,” Monfort says. “If we cut the rate to one half or three fourths of the recommended rate, we should still see benefits.” One of the reasons Monfort started studying Apogee was that he started receiving calls about the Georgia-12Y variety and its excessive vine growth. Monfort says the PGR may have its greatest benefits for varieties released since Georgia-06G became popular. “The newer varieties seem to grow more vine,” Monfort says. Early on in his tests, Monfort realized that Apogee would need to boost yields, not just control vine growth, to justify its use in runner peanuts. His initial goal was to obtain 200 to 500 additional pounds of peanuts per acre from a half rate application program for Apogee. Chad Abbott, a research and Extension associate at Mississippi State University, has also taken part in testing prohexadione calcium on runner peanuts. The tests took place last year on farms in Coahoma, Holmes and Forrest counties of Mississippi. The rates tested were 50 percent, 75 percent and 100 percent of the fully labeled rate. These rates correspond to 3.63, 5.4 and 7.25 ounces per acre. The test sites in Coahoma and Holmes counties were furrow irrigated while the farm in Forrest County was center pivot irrigated. The varieties in the test included TUFRunnerTM ‘297’ in Coahoma County, TUFRunnerTM ‘511’ in Holmes County and Georgia-06G in Forrest County. “With the full labeled rate, we saw clearly defined rows that we did not see in the untreated rows,” Abbott says. “Also, the plants were clearly darker green in color after the first treatment. We
75 percent rate of Apogee 5.4 ounces per acre
saw a significant reduction in plant biomass with the PGR. The untreated plant height was about 21 inches while the treated plants had a height of about 15 inches.” In the Mississippi tests, the 75 percent rate provided the best returns, though the 50 percent rate was also profitable, according to Abbott. The tests showed overall yields of 6,883 pounds per acre for those at the 75 percent rate, 6,776 pounds per acre at the 100 percent rate, 6,626 pounds per acre for the 50 percent rate and 6,145 pounds per acre for the untreated peanuts. Assuming peanuts are valued at $475 per ton, and given the cost of Apogee, a yield increase of 250 pounds per acre would allow growers to break even on application costs at the full labeled rate, according to Abbott. However, an extra yield of 188 pounds per acre would cover application costs at the 75 percent rate and a yield boost of 125 pounds per acre would cover costs at the 50 percent rate. Growers need to consider that Apogee is an expensive product to apply by itself, according to Abbott. He says growers would need to look at the mixing of fungicides, insecticides and herbicides with the plant growth regulator. He also notes that growers should make sure there are no phytotoxicity issues from the crop oil concentrate that is added to the product. While the Mississippi tests did not measure digging efficiency, Abbott says it appeared that peanut inverters performed better where the PGR was applied. Based on the Mississippi tests, it appears that the use of Apogee will allow combine harvesting a day earlier than normal. In these tests, the height of viney peanuts was reduced by about four to five inches. The highest yields in these tests occurred when Apogee was applied at 75
Full rate of Apogee 7.25 ounces per acre
percent of the full labeled rate. One of the places where Monfort tested Apogee was on the farm of Mike Newberry near Arlington, Georgia. Newberry plants peanuts after heavily fertilized corn, and deals with heavy vines every year. He grows the Georgia-06G variety and says the vines became such a problem that he started mowing them prior to digging. The mowing also seemed to improve field drying. Based on his experience, Newberry plans to eliminate the mowing trip where he uses Apogee. And this year, he plans to use the product on all of his peanuts except those planted after May 25. His standard rate will be at 75 percent of the full rate. He also wants to test the full labeled rate in two applications and in one application. He may also test prohexadione calcium applied with fungicides. He’s not sure that fungicides will be compatible since a crop oil concentrate and a nitrogen solution are needed to move the plant growth regulator into the peanut plants. Newberry said the prohexadione calcium caused the peanut vines to turn a dark green in color, and he noticed that the second application did a good job of limiting the regrowth of the vines. Since prohexadione calcium is primarily used in apples and turfgrass, it can be difficult to obtain in peanut farming areas, according to Newberry. Newberry was impressed with the higher yields from the Apogee-treated peanuts. “They were easier to invert and we were able to run the picker in a faster gear,” he recalls. “We were able to run our pickers a day sooner for the treated peanuts.” Best of all, Newberry’s PGR-treated peanuts were much higher yielding than those not treated with the prohexadione calcium. t BY JOHN LEIDNER
May/June 2018 Southeastern Peanut Farmer