Own-rooted four-year-old kiwifruit plants (Actinidia deliciosa) protected by a Reese clip-on styrofoam insulation trunk wrap, or microsprinkler irrigation, sustained less freeze injury than unprotected plants under field conditions at temperatures as low as -17.8C. Trunk splitting occurred on the plants but no injury was detected on canes, buds, or shoots in the canopy of the plants. Unprotected plants had more trunk splitting and at greater heights than protected plants. New canes developed from suckers of cold-injured plants and developed a filled canopy the following season.
D.G. Himelrick, W.A. Dozier Jr., and A.W. Caylor
A.W. Caylor, W.A. Dozier Jr., and J. Pitts
Latron AG-98 (formerly named Triton AG-98) was applied to 8-year-old `Surecrop' peach trees on Lovell rootstock at 0%, 2%, 4%, and 6% (v/v) on 13 Mar. 1990 and 1992 and 28 Mar. 1991. Our objective was to determine the effect Latron AG-98 had on percentage of blossoms removed, fruit set, total fruit count and yield, and marketable fruit weight. The percentage of blossoms removed increased with increasing rates of Latron AG-98. The 4% and 6% rates removed the greatest percentage of blooms in all 3 years. The number of fruit per 50 cm of shoot length, number of fruit removed by hand-thinning, percent fruit set, total fruit number, and total fruit yield decreased with increasing rates of Latron AG-98 in 1990 and 1992 but not in 1991. The marketable fruit weight increased with increasing rates of Latron AG-98 in 1990 and 1992 but not in 1991. Latron AG-98 was not effective in 1991 because of a 2-day delay in application. Latron AG-98 was effective in removing blossoms from `Surecrop' peach at all three rates. However, the 4% and 6% rates reduced the yields below a commercially acceptable level. The 2% rate of Latron AG-98 could be useful as a tool to reduce the labor required to hand-thin peaches.
R.C. Ebel, D.G. Himelrick, A. Caylor, and J. Pitts
The surfactant “Surfactant WK” (dodecyl ether of polyethylene glycol) was applied to peach trees [Prunus persica (L.) Batsch] at full bloom over 3 years. Blossoms died rapidly so that within 2 days dead blossoms could be distinguished easily from live blossoms or set fruit. There were strong (R 2 > 0.87), linear correlations between concentration of “Surfactant WK” applied and percent blossoms removed and fruit set, which were similar over the 3 years. Trees were hand-thinned according to commercial practices after treatment. There was similar cropload, fruit weight, and yield across treatments at harvest indicating no negative effects by the chemical on productivity. There was only slight limb damage at the highest concentrations of “Surfactant WK,” which overthinned blossoms. We recommend that based on the effectiveness, consistency, and lack of significant phytotoxicity, “Surfactant WK” be reevaluated as a thinning chemical for peach trees.
A. Caylor, W. Dozier, D. Himelrick, J. Pitts, and L. Chapman
Four year old `Loring' peach trees on `Lovell' rootstock were treated with single applications of 0, 50, and 100 ppm GA3 alone and in combination with 100 ppm ethephon on 15 November 1988, 1989, and 1990 to determine the effect on bloom delay the following spring. Flower bud number was not affected by any of the treatments the next spring. Ethephon had the greatest effect on bloom delay the following spring. The 50 and 100 ppm GA3 treatments resulted in a slight delay of bloom. The combination of 50 and 100 ppm GA3 and 100 ppm ethephon resulted in less of a bloom delay than ethephon alone but greater than the GA3 treatments alone. Fruit set was increased by ethephon treatments in 1989 and 1991 but not in 1990. Ethephon treatments delayed fruit maturity whereas GA3 did not. Total fruit yield for 1989, 1991, and the three year average was not effected by treatments. However, in 1990 50 ppm GA3 resulted in the highest yields. Ethephon treatments reduced the average fruit weight in 1990 and 1991 but not in 1989 or the three year average.
W.A. Dozier Jr., A.A. Powell, A.W. Caylor, N.R. McDaniel, E.L. Carden, and J.A. McGuire
Hydrogen cyanamide (Dormex) treatments were applied to 17 insufficiently chilled peach and nectarine cultivars ≈6 weeks after normal budbreak. Treatment effectively induced vegetative budbreak and reduced shoot dieback. The responses to Dormex treatments were linear, with the 2% rate being more effective than the 0 and 1% rates in most cases.
A.W. Caylor, W.A. Dozier Jr., G. Wehtje, D.G. Himelrick, J.A. McGuire, and J.A. Pitts
The postemergence-active herbicides lactofen, fomesafen, and acifluorfen were applied to established matted-row strawberry plants (Fragaria × ananassa) and evaluated for broadleaf weed control and foliar phytotoxicity. Strawberries were evaluated for yield and fruit quality. Treatments were applied following June renovation. All herbicide treatments resulted in acceptable control of broadleaf weeds present at the time of application; however, sicklepod (Cassia obtusifolia) germinated after herbicide application. All treatments caused foliar injury within 3 days after application. No injury symptoms were evident 21 days after treatment due to new foliage development. Fomesafen and acifluorfen were the only herbicides to suppress runner count. Yields the following year were not reduced by herbicide treatments. Chemical names used: (±)-2-ethoxy-l-methy1-2-oxoethyl 5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-nitrobenzate (lactofen); 5-[2-chloro-4-(trifluoromethyl)phenoxy] -N -(methylsu1fonyl)-2-nitrobenzamide (fomesafen); 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen).
W.A. Dozier Jr., R. Rodriguez-Kabana, A.W. Caylor, D.G. Himelrick, N.R. McDaniel, and J.A. McGuire
The yellow passionfruit (Passiflora edulis f flavicarpa Degener), a perennial vine grown in the tropics and subtropics, was successfully grown as an annual crop in a temperate zone. Fruit maturity was hastened by ethephon treatments to allow harvest before the mean date of the first killing frost. Maturity was advanced in a linear manner with application rates of 150, 300, and 600 ppm ethephon. Total yield was not affected by ethephon treatment; however, cull fruit producing no juice increased with increasing rates of ethephon, thereby reducing marketable yields. Soluble solids and ascorbic acid contents of the juice were not affected by ethephon treatment. Purple passionfruit (Passiflora edulis Sims) did not produce blossoms.
W.A. Dozier Jr., A.W. Caylor, D.G. Himelrick, A.A. Powell, A.J. Latham, J.A. Pitts, and J.A. McGuire
Own-rooted, 4-year-old kiwifruit plants [Actinidia deliciosa (A. Chev.) C.F. Liang et R. Ferguson var. deliciosa] protected by a Styrofoam insulation wrap with a water-filled pouch (Reese clip-on trunk wrap) or by microsprinkler irrigation sustained less freeze injury than unprotected plants under field conditions at temperatures as low as -17.8C. Trunk splitting occurred on the plants, but no injury was detected on canes, buds, or shoots in the canopy of the plants. Unprotected plants had more trunk splitting and at greater heights than protected plants. New canes developed from suck- ers of cold-injured plants and developed a trellised canopy the following season.
R.C. Ebel, W.A. Dozier Jr., M.L. Nesbitt, N.R. McDaniel, A.A. Powell, A. W. Caylor, and W.R. Okie
There are a limited number of peach and nectarine cultivars available with chilling requirements that perform well in the Gulf Coast area of Alabama. A test planting of 40 peach and 13 nectarine cultivars was established in 1985 at the Gulf Coast Substation at Fairhope, Ala. The plot was prepared and trees grown according to commercial procedures. Blocks of four trees of each cultivar were planted on a 6 x 6-m spacing. Chill hours were calculated each year based on number of hours at or below 7.3 °C; starting from and including the first 10 consecutive days a total of 50 hours were accumulated to 15 Feb. Data collected included date of full bloom, first harvest date, and total yield. Fruit were measured or rated for skin color, attractiveness, firmness, stone freeness, pubescence, flesh color, dessert quality, shape, weight, percentage with split pits, and occurrence of malformed sutures and extended tips. All cultivars were evaluated for 9 years (1987–95). The best performing varieties are discussed.