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Abstract

A combination of succinic acid-2,2-dimethylhydrazide (daminozide), (2-chloroethyl)-phosphonic acid (ethephon) and straight chain fatty alcohols (Off-Shoot-T85) or methyl esters of straight chain fatty acids (Off-Shoot-0) applied 30 days after bloom to nonbearing ‘Topred Delicious’ apple trees (Malus domestica Borkh.) induced spur development on current season growth, increased the number of flower buds per tree, and suppressed terminal growth, one-year-old shoot diameter, and trunk diameter. The combination of daminozide and ethephon did not induce spurs to develop on current season growth; however, slightly enlarged buds on one-year-old growth flowered the spring following treatment.

Open Access
Authors: and

In 1995, BAS-125W applied at 125 to 500 mg/liter 23 days after full bloom (AFB) to `Starkrimson Delicious'/MM 106 and MM111 reduced average shoot weight and length of the longest shoots in the top and scaffold limbs by 50% at the highest rate. The number of nodes on the lower 40 cm of each shoot was increased by 1.8 times by the growth retardant. The number of pruning cuts, pruning time, and pruning weight per tree was reduce by 30%, 20%, and 29%. Fruit diameter, color, soluble solids, starch, fruit weight, and fruit number per tree were not altered by BAS-125 W. Growth suppression appeared to be greater on trees with heavier crop loads. In 1996, BAS-125W applied at 250 mg/liter 8 days after full bloom was more effective than when applied 19 days AFB to `Starkrimson Delicious'/MM 106 and MM111. Multiple applications of two, three, and four sprays to the same trees at 3-week intervals further reduced shoot growth with each application. Four applications reduced shoot weight by 72%, shoot length by 60%, and basal shoot diameter by 25%, and the number of pruning cuts, pruning time, and pruning weight per tree was reduce by 75%, 55%, and 80%, respectively. Thinning activity of NAA, Sevin, or Accel was not affected by tank mixed sprays with BAS-125W when applied to Gala/M.27 trees 20 days AFB. Tank mixing BAS-125W with combinations of Vydate + Accel or Carbaryl + Accel + Oil did not alter fruit thinning of Fuji/M.27 (at 10 mm fruit diameter). In one experiment, BAS-125 may have potentiated thinning by ethephon and NAA 10 days AFB in another experiment. BAS-125 W sprays at petal fall + 1 and 2 weeks later significantly suppressed % infection by fireblight, Erwinia amylovora, in inoculated shoots. In addition, BAS-125W reduced canker length in the first-year growth in shoots inoculated 2 weeks after treatment.

Free access
Authors: and

Peach trees [Prunus persica (L.) BatSch.] blossom-thinned by hand were overthinned due to poor fruit set of the remaining flowers; however, their yield was equivalent to trees hand-thinned 38 or 68 days after full bloom (AFB). Blossom-thinned trees had three times the number of flower buds per unit length of shoot and had more than two times the percentage of live buds after a March freeze that had occurred at early bud swell the following spring. Blossom-thinned trees were more vigorous; their pruning weight increased 45%. For blossom-thinned trees, the number of flowers per square centimeter limb cross-sectional area (CSA) was two times that of hand-thinned trees and four times that of the control trees for the next season. Fruit set of blossom-thinned trees was increased four times. Flower buds on the bottom half of shoots on blossom-thinned trees were more cold tolerant than when hand-thinned 68 days AFB. Fruit set per square centimeter limb CSA was 400% greater the following year on blossom-thinned trees compared to controls. Removing strong upright shoots on scaffold limbs and at renewal points early in their development decreased dormant pruning time and weight and increased red pigmentation of fruit at the second picking. The number of flower buds per unit shoot length and percent live buds after the spring freeze were negatively related to crop density the previous season for trees that had been hand-thinned to varying crop densities at 48 days AFB. According to these results, blossom thinning and fruit thinning to moderate crop densities can influence the cold tolerance of peach flower buds in late winter.

Free access
Authors: and

Apple growers of different regions need different chemical fruit-thinning responses for thinning trees of different tree ages, cultural conditions, rootstocks, climates, and amounts of fruit removal desired. In this research, a range of chemical thinning responses was achieved by combinations of thinning materials or addition of potentiating agents. Superior oil, certain organic phosphates, and a light-absorbing agent (ferbam, a fungicide) increased the thinning of carbaryl. In addition, combinations of 50 or 200 ml 6-BA/liter + carbaryl + oil defruited `Campbell Redchief Delicious'/M.111 trees, and 50 ml 6-BA/liter alone over-thinned in one year (however, oil or 6-BA has been shown previously to cause russet in `Golden Delicious'). Carbaryl 50 WP and the 4L carbaryl formulations were equally effective for thinning `Golden Delicious', `Stayman', and `Redspur Delicious', and did not affect fruit russet. Three days of cloudy weather is typical at least once in most seasons in the eastern United States during the fruit set period. Two days of artificial polypropylene shading (92%) (which was nearly equivalent to 3 days of cloudy weather) caused more thinning of `Golden Delicious' and `Stayman' than carbaryl or 10 mg NAA/liter + Tween. Shading reduced viable seed numbers about 50% for `Golden Delicious' in fruit remaining at harvest, but chemical thinning agents (NAA or carbaryl) did not affect viable seed number.

Free access
Authors: and

Abstract

Pine vole, Microtus pinetorum LeConte, activity in an apple orchard was reduced by cultivation of a 4 m-wide strip down the tree row. Bare-ground-culture using a single annual application of Simazine plus Amitrol (1964-71) or Paraquat (1972-73) herbicide for 10 years reduced pine vole activity.

Open Access

Abstract

Rodenticides applied in an apple orchard and containing zinc phosphide caused a shift in mixed pine (Microtus pinetorum) and meadow (M. pennyslvanicus) vole populations to more pine voles. The anticogulant, chlorophacinone (Rozol-pelleted formulation, CPN) caused a shift to more meadow voles. A lacquered wheat formulation of CPN was as effective as the Rozol-pelleted formulation when broadcast or hand-placed under shingles and appeared to weather better than Rozol. Cholecalciferol (Quintox-pelleted formulation) and one of the zinc phosphide (Ridall-pelleted formulation) formulations were not effective rodenticides. Chemicals used: 2-(p-chlorophenyl) phenylacetyl [-1,3-indanione [Rozol 0.005% chlorophacinone (CPN)]; 3-[3-(4’-bromo[1,1’-biphenyl]-4-y)-3-hydroxy-l-phenylpropyl]-4-hydroxy-2H-1-benzopyran-2-one [Maki 0.005% Bromodialone (BDL)]; cholecalciferol [Quintox 0.075% Vitamin D3 (vit D3)]; Zn3P2 pellet zinc phosphide [ZP Rodent Bait AG —2%, W-ZP Rodent Bait AG Zinc phosphide (ZnP)].

Open Access
Authors: and

Abstract

Five commercially available zinc phosphide (Zn3P2) preparations were tested in a 3-day, free choice trial for efficacy on meadow voles (Microtus pennsylvanicus) and pine voles (M. pinetorum). A 2% Zn3P2 pellet produced a significantly greater and quicker kill in meadow voles than a 2% Zn3P2 oat-corn bait. Whole oat and cracked corn baits (2% Zn3P2) performed as well on meadow voles as did a 1% Zn3P2 paraffinized pellet. The 2% Zn3P2pellet produced significantly greater mortality in pine voles than did 2% Zn3P2 oat-corn and whole oat baits and a 1 % paraffinized pellet. There was no evidence that grain baits were more effective for meadow voles than pine voles.

Open Access

Abstract

Limb applications of 5% or 10% alkaryl polyoxyethylene alcohols (X-77 or X- 45) caused flower bud removal when applied to peach trees [Prunus persica (L.) Batsch] with a hand pump sprayer from first pink to 90% bloom. Applications made in late pink or bloom period caused a greater reduction in fruit set than earlier treatments. Applications made at 90% bloom caused some phytotoxicity to the tips of the first small leaves but did not affect the growth of the terminal vegetative primorida or of larger leaves produced on later terminals. Thinning appeared to be commercially acceptable when applied between 30% and 90% bloom. Fruit size at harvest was greater than the unthinned control. Airblast applications of 10% X-77 on the ‘Loring’ cultivar reduced fruit set about 40%.

Open Access

Abstract

Airblast applications of ammonium nitrate, ammonium thiosulfate, an oxylated alcohol surfactant (SN-50), or 7-oxabicyclo-(2,2,1) heptane-2,3-dicarboxylic acid (endothall) to peaches [Prunus persica (L.) Batsch] in bloom reduced fruit set and increased fruit size on several cultivars. Foliage injury was minimal when applied at bloom. Applications of these chemicals 6 days post-bloom to ‘Redhaven’ trees caused unacceptable foliage injury and did not cause fruit abscission. Several other surfactants and fertilizers were found to have caustic action in laboratory trials, but fruit set on ‘Redhaven’ was not reduced in field airblast trials.

Open Access

Abstract

Field efficacy of the Ramik-Brown formulation against pine voles was improved by increasing the concentration of diphacinone (DPN) from 0.005% to 0.216%. A 10-fold increase in diphacinone concentration in the Ramik-Brown formulation increased mortality of meadow voles (5% to 25%) in a laboratory cage trial without affecting bait consumption. The Ramik-Green formulation (fish-flavored) was equally effective for control of pine voles as the Ramik-Brown (apple-flavored). Chemical names used: 2-diphenylacetyl-1,3-indandione (diphacinone).

Open Access