Control of pudding spot in Crofton apple

1992 ◽  
Vol 32 (4) ◽  
pp. 503
Author(s):  
KM Jones ◽  
SA Bound ◽  
MJ Oakford ◽  
TB Koen
Keyword(s):  
Acetic Acid ◽  
Fruit Size ◽  
Fruit Weight ◽  
The Other ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Apple Trees ◽  
Low Incidence ◽  
Thinning Effect

Regularly cropped Crofton apple trees in southern Tasmania were thinned using sprays of naphthalene acetic acid (NAA) at 10 mg/L or ethephon at 200 mg/L at balloon blossom (BB), full bloom (FB), 10 days after full bloom (DAFB) or 20 DAFB. These treatments were compared with hand thinning and an unthinned control. Ethephon had a uniformly mild thinning effect (about 30% compared to control), except at 10 DAFB, where no thinning occurred. NAA was inconsistent, thinning well at BB (50%), overthinning at both FB (85%) and 10 DAFB (88%), and underthinning at 20 DAFB (similar to the control). Ethephon applied at BB and FB increased both mean fruit weight (12 and 22%) and fruit size (28 and 79%), but later applications did not. NAA applications generally resulted in increased mean fruit weight and size, except for the 20 DAFB treatment, which was similar to the control. All ethephon treatments had a low incidence (43%) of pudding spot similar to the controls and hand-thinned treatments. Most NAA treatments showed significantly higher levels of pudding spot than the other treatments. It is concluded that ethephon is a more predictable thinner for Crofton than NAA, and its use to control pudding spot is recommended.

Thinning Golden Delicious apples with pre-bloom naphthalene acetic acid and later carbaryl sprays

1984 ◽  
Vol 24 (126) ◽  
pp. 453 ◽  
Author(s):  
KM Jones ◽  
TB Koen ◽  
RJ Meredith
Keyword(s):  
Acetic Acid ◽  
Fruit Size ◽  
Fruit Weight ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Golden Delicious

A trial in southern Tasmania examined the thinning effects of naphthalene acetic acid (NAA) on Golden Delicious apples. The NAA was applied at pink bud or balloon blossom at 12, 18 and 24 ppm, with or without carbaryl at 1800 ppm applied 10 d after full bloom. Carbaryl was also applied alone 10 and 20 d after full bloom, and a hand thinned treatment was included. The higher concentrations of NAA did the most thinning but only the hand-thinned and 24 ppm NAA at balloon blossom with carbaryl treatment thinned enough to produce the required fruit size. The NAA sprays at balloon blossom thinned considerably more than those at pink bud. Neither NAA nor carbaryl alone was as effective as the combination. Reduction of fruit numbers increased mean fruit weight from 101 g in the control to 149 g in the 24 ppm NAA at balloon blossom with carbaryl. There was no evidence that increasing the concentration of NAA reduced mean fruit weight. This trial demonstrates that the effect of balloon stage sprays of NAA combined with later carbaryl sprays on Golden Delicious is similar to that achieved by the normal practice of spraying with NAA 7-14 d after full blossom, followed by carbaryl at 20 d. Reduction from 128 fruit/ 100 blossom clusters in the control to 76 after spraying at balloon blossom is still outside present aims of 30-50 fruit and is not considered to be severe enough thinning to assure adequate fruit size.

A comparison of air-shear and electrostatic spray technology with a conventional air-blast sprayer to thin apples

1994 ◽  
Vol 34 (5) ◽  
pp. 669 ◽  
Author(s):  
MJ Oakford ◽  
KM Jones ◽  
SA Bound ◽  
L O'Rielly
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
High Volume ◽  
The Other ◽  
Full Bloom ◽  
Apple Trees ◽  
Air Blast ◽  
Fruit Number ◽  
Low Volume ◽  
Electrostatic Spray

Red Delicious apple trees at Spreyton in northwest Tasmania were thinned with ethephon using an air-shear-electrostatic sprayer (low volume: 100 or 200 L/ha with or without electrostatics) or a commercial air-blast sprayer (high volume: 2000 or 4000 L/ha). Treatments were applied at 2 and 10 days after full bloom. Also included were an unsprayed control and a hand-thinned treatment (15-20 days after full bloom). Carbaryl + Thiram was also applied 3 times (20, 32 and 40 days after full bloom) using the same spray treatments. All dosage rates were equilibrated to apply the same amount of active ingredient/ha. The spray treatments thinned fruit more than the controls when compared for fruit number and all size variables measured except percentage of fruit >80 mm. There were significant differences for fruit number between the hand-thinned, 4000 L/ha high volume and 200 L/ha air-shear treatments, and all the remaining treatments. This applied to both total numbers of fruit set or numbers of fruit hand-thinned at 80-90 days after full bloom. This late hand-thinning had the effect of evening up the fruit size but the control still had significantly smaller fruit than all the other treatments due to the larger number of fruit carried through to hand-thinning.

Preliminary examination of thinning strategies on young ‘Jonagold’ and ‘Pink Lady’ apples

1997 ◽  
Vol 37 (3) ◽  
pp. 377 ◽  
Author(s):  
K. M. Jones ◽  
S. A. Bound ◽  
C. R. Summers ◽  
M. J. Oakford
Keyword(s):  
Fruit Size ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Naphthalene Acetic Acid ◽  
Fruit Firmness ◽  
Full Bloom ◽  
Quality Outcomes ◽  
Chemical Treatments ◽  
Combination Treatments ◽  
Preliminary Examination

Summary. Strategies were examined for thinning 5-year-old apple trees of ‘Jonagold’ and ‘Pink Lady’ with chemical thinners. Both cultivars were left unthinned (control), hand-thinned at 20 days after full bloom (DAFB) or chemically thinned. The chemical treatments consisted of full bloom (FB) sprays of naphthalene acetic acid (NAA) at 2.5, 5 or 10 mg/L or ethephon at 25, 50 or 100 mg/L or combination treatments of 2.5, 5 or 10 mg NAA/L at FB followed by 50 mg ethephon/L at 7 DAFB. In addition 5 mg NAA/L or 50 mg ethephon/L were followed by 150 mg CyLex/L (6-benzyladenine, Abbott Laboratories) at 20 DAFB. Neither NAA, ethephon alone or NAA followed by ethephon were effective at the 2 lower concentrations. The highest level of NAA with ethephon did some thinning of ‘Pink Lady’ but overthinned ‘Jonagold’. The CyLex combination treatments were the most effective. Combining NAA and CyLex did not thin enough to increase fruit size in ‘Pink Lady’ and slightly overthinned ‘Jonagold’. The most effective treatment of ethephon and CyLex removed about half the crop load compared with the control for both cultivars. This resulted in a 29% increase in fruit weight and a 48% increase in fruit size for ‘Jonagold’. ‘Pink Lady’ increases were less, being 16% for fruit weight and 38% for fruit size. All mean fruit weight and size outcomes for the ethephon–CyLex treatment exceeded provisional targets. The ethephon–CyLex combination had important fruit quality outcomes other than fruit weight and size. Fruit soluble solids were increased by this treatment by 10% for ‘Jonagold’ and 6% for ‘Pink Lady’ and fruit firmness by 11% for ‘Jonagold’ and 5% for ‘Pink Lady’. The overall results for the ethephon–CyLex combination were most encouraging for both cultivars. Further work is required to substantiate these results.

Further studies on the use of 2-chloroethyl-phosphonic acid (ethephon) as a thinning agent for apples

1979 ◽  
Vol 19 (100) ◽  
pp. 611 ◽  
Author(s):  
N Veinbrants
Keyword(s):  
Acetic Acid ◽  
Phosphonic Acid ◽  
Growth Regulator ◽  
Fruit Size ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Golden Delicious ◽  
Apple Cultivars ◽  
Series Of Experiments

In a series of experiments the growth regulator 2-chloroethylphosphonic acid (ethephon) at concentrations from 50 ppm to 400 ppm was applied at various stages during and after flowering to apple cultivars Golden Delicious, Gravenstein, Jonathan, Richared and Starkrimson. On the heavy setting Golden Delicious, Gravenstein and Jonathan cultivars, adequate thinning and satisfactory fruit size was obtained when ethephon at 100 ppm was applied at or shortly after full bloom, followed by naphthalene acetic acid. On the lighter setting Richared and Starkrimson cultivars, one ethephon spray at 100 ppm applied at or shortly after full bloom resulted in adequate thinning. All fruit were eliminated on Jonathan, Richared and Gravenstein cultivars when ethephon was applied at 400 ppm, 300 ppm and 200 ppm, 36, 35 and 42 days after full bloom, respectively.

scholarly journals Commercial-scale Use of Hydrogen Cyanamide for Apple and Peach Blossom Thinning

1998 ◽  
Vol 8 (4) ◽  
pp. 556-560 ◽  
Author(s):  
Esmaeil Fallahi ◽  
Randy R. Lee ◽  
Gary A. Lee
Keyword(s):  
Acetic Acid ◽  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Hydrogen Cyanamide ◽  
Air Blast ◽  
Fruit Thinning ◽  
Commercial Scale

Hydrogen cyanamide (Dormex, 50% a.i.) for blossom thinning `Early Spur Rome' and `Law Rome' apple (Malus×domestica Borkh.) and `Flavorcrest' peach (Prunus persica L.) was applied with air-blast sprayers on a commercial scale. Full-bloom applications of hydrogen cyanamide at 4 pts formulation per 200 gal/acre (1288 mg·L−1) and 5 pts formulation per 200 gal/acre (1610 mg·L−1) significantly reduced fruit set in apple and peach. In `Early Spur Rome', a postbloom application of carbaryl [Sevin XLR Plus, 4 lb a.i./gal (0.48 kg·L−1)] following a full-bloom spray of hydrogen cyanamide increased fruit thinning with a significant increase in fruit size compared to an application of hydrogen cyanamide alone. In `Law Rome', trees receiving a full-bloom application of hydrogen cyanamide followed by a postbloom application of 1-naphthyl-N-methylcarbamate (carbaryl) + naphthalene acetic acid (NAA) had significantly lower fruit set and larger fruit than those in the carbaryl + NAA treatment. Apples or peaches were not marked by hydrogen cyanamide.

scholarly journals 184 Timing of Benzyladenine Application as a Chemical Thinner of `Empire' Apple

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 455d-455 ◽  
Author(s):  
V. E. Emongor ◽  
D. P. Murr
Keyword(s):  
Fruit Quality ◽  
Ethylene Production ◽  
Fruit Set ◽  
Fruit Size ◽  
Fruit Weight ◽  
Seed Number ◽  
Full Bloom ◽  
Apple Trees ◽  
Effective Time ◽  
Fruit Diameter

Benzyladenine (100 or 200 mg.litre-1) was applied to mature Empire/M.26 apple trees as dilute sprays 2, 4, 9, 11, 13, 15, 17, 20, 25, 27, 29 or 31 days after full bloom (DAFB). The most effective time of thinning was 25-29 DAFB (king fruit diameter 8.94-13.91 mm), and the thinning response to BA concentration was linear. Benzyladenine (BA) did not reduce fruit set when king fruit diameter was less than 5.35 mm, but BA significantly increased fruit weight, diameter (D), length (L) and L:D ratio compared to unsprayed controls and later BA treatments. BA - treated fruitlets had higher ethylene production, 24 hours and 7 days after spraying compared to untreated controls. We suggest that the response of apple fruitlets to BA applied as a thinner is mediated by ethylene. High fruit quality was obtained when BA was applied at 17-31 DAFB. Timing of BA sprays had no effect on seed number, though BA significantly increased seed number, fruit size, weight and L:D ratio. These results suggest that BA has the potential to substitute for the use of carbaryl as a thinner of apples in Ontario orchards.

scholarly journals Chemical Thinning of Loquat with Naphthalene Acetic Acid

2003 ◽  
Vol 13 (1) ◽  
pp. 128-132
Author(s):  
Bruno Razeto ◽  
Gabino Reginato ◽  
Sergio Rojas
Keyword(s):  
Acetic Acid ◽  
Fruit Size ◽  
High Rate ◽  
Eriobotrya Japonica ◽  
Naphthalene Acetic Acid ◽  
Cross Sectional ◽  
Fruit Number ◽  
Fruit Thinning ◽  
Sigmoid Curve ◽  
Thinning Effect

Loquat (Eriobotrya japonica) belongs to the subfamily Pomoideae, and is an evergreen fruit tree which blooms in fall. Its inflorescence is a panicle. To attain commercial fruit size fruit thinning is done by hand. A chemical thinning trial was performed during the 1999-2000 growing season in Peumo, Cachapoal County, Sixth Region, Chile. Sixteen-year-old `Golden Nugget' loquat trees were treated with naphthalene acetic acid (NAA) at rates of 70, 140, and 280 g·ha-1 (1.0, 2.0, and 4.0 oz/acre), split into two or three applications beginning at early fruit set followed with sprays, 13 and/or 28 days later. Each treatment was applied to four randomly selected trees. At harvest, fruit number was measured in four panicles per tree and in the whole tree. NAA produced a thinning effect closely related to dose, with the highest doses inducing both highest flower thinning and the largest size of the fruit, but the lowest yield per tree. Lower doses produced fruit size and yield similar to those of hand-thinned check trees. Fruit load, expressed as trunk cross sectional area (TCSA), reached 1.8 to 9.1 fruit/cm2 TCSA (11.6 to 58.7 fruit/inch2 TCSA) in treated trees in comparison to 20 fruit/cm2 TCSA (121 fruit/inch2 TCSA) of the nontreated trees. NAA treatments did not affect the number of seeds per fruit. Total dose of 140 g·ha-1 NAA was the most effective in reducing fruit number, whether split into two or three applications. Fruit development seemed to conform to a double sigmoid curve, with a high rate of growth during fall, a lower one through the winter, in order to recover the growth rate in spring until maturity.

scholarly journals (99) Using Naphthalene Acetic Acid, Prohexadione-Ca, Ethephon, and Scoring to Reduce Vegetative Growth in Upper Canopy of Apple Trees

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1030C-1030
Author(s):  
Wesley R. Autio ◽  
James Krupa ◽  
Jon M. Clements ◽  
Duane W. Greene
Keyword(s):  
Acetic Acid ◽  
Vegetative Growth ◽  
Shoot Growth ◽  
Fruit Set ◽  
Extension Growth ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Treatment Area ◽  
Latex Paint ◽  
Apple Trees

In 2004, at full bloom, 3-year-old `Cameo'/G.16, `Gala'/M.9 NA-KBT337, `Gala'/G.16, and `Redmax'/B.9 apple trees were treated with naphthalene acetic acid (NAA, 1.5% in latex paint) in a 7.5-cm band completely around the central leader at the base of 2-year-old wood. NAA treatment reduced 2004 extension growth of the central leader by 14% and total shoot growth above the treatment area by 32%. `Cameo'/G.16 trees also were sprayed with prohexadione-Ca (250 ppm with surfactant and water conditioner) at full bloom, and additional trees were sprayed with ethephon (500 ppm with surfactant) 1 week after full bloom. These spray treatments were made only to the stems and foliage from the base of the central leader's 2-year-old wood to the top of the canopy. Ethephon reduced total shoot growth in 2004 by 26%, and prohexadione-Ca reduced it by 63%. Prohexadione-Ca also reduced fruit set of `Cameo' in 2004. Scoring (single knife cut completely around the circumference of the trunk) at the base of the 2-year-old wood in the `Cameo' trees resulted in a 23% reduction in leader growth and a 22% in totals shoot growth in the upper canopy in 2004. In 2005 at full bloom, 4-year-old `Golden Delicous'/B.9 trees were treated with NAA similarly to trees in 2004, except treatment at the base of 2-year-old wood was compared to treatment at the base of 1-year-old wood. Treating the base of 1-year-old wood reduced growth to a greater degree than comparable treatment at the base of 2-year-old wood. For the 1- and 2-year-old-wood treatments, the number of laterals produced from the 1-year-old wood was reduced 42% and 17%, and total shoot growth from 1-year-old wood was reduced by 49% and 31%, respectively.

Blossom Thinning in Pome and Stone Fruit

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 553b-553
Author(s):  
Esmaeil Fallahi
Keyword(s):  
Fruit Size ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Flower Bud ◽  
Hydrogen Cyanamide ◽  
Ammonium Thiosulfate ◽  
The Past ◽  
Apple Cultivars ◽  
Ortho Cresol ◽  
Bud Initiation

Early thinning of apples is important because of its impact on fruit size and next season's flower bud initiation. In the past, apple cultivars were often sprayed with the blossom thinner sodium dinitro-ortho-cresol(Elgetol) during full bloom, followed by a post-bloom application of a fruit thinner such as carbaryl with or without naphthalene acetic acid (NAA). Elgetol was removed from the market in 1989 because of the high cost of re-registration. Full-bloom sprays of sulfcarbamide (Wilthin), pelargonic acid (Thinex), and endothalic acid (Endothal), ammonium thiosulfate (ATS) or petal fall spray of carbaryl (Sevin XLR Plus) were developed as replacements for Elgetol. Hydrogen cyanamide (HC) and other chemicals have been used to eliminate or to reduce chilling requirements of peaches grown under the warm desert conditions. HC applied at “pink bloom” stage was observed to reduce the number of open blooms in `Florda Prince' peach; therefore, it was first used for blossom thinning in this cultivar in Arizona. Later, HC was also found to be an effective blossom thinner for plums in Idaho. HC has recently been found to effectively thin apple and peach blossoms. Armothin has also been an effective blossom thinner for peach in California.

scholarly journals AN EVALUATION OF BENZYLADENINE AS A POSSIBLE CHEMICAL THINNER OF “EMPIRE”

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 592a-592
Author(s):  
V.E. Emongor ◽  
D.P. Murr ◽  
J.T.A Proctor ◽  
E.C. Lougheed
Keyword(s):  
Field Trials ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Research Station ◽  
Full Bloom ◽  
Ethylene Concentration ◽  
Solids Concentration ◽  
Cambridge Research ◽  
Thinning Effect ◽  
Soluble Solids Concentration

Field trials at Cambridge Research Station, Ontario, Canada, studied the thinning effect of benzyladenine (BA) on eighteen-year-old “Empire” apple trees. At 16 days after full bloom (fruit diameter 12.87 mm) whole trees were hand sprayed to drip point with BA (0, 100, or 200 mg.1-1). Untreated control trees were compared with treated and hand thinned trees. BA significantly reduced crop load on “Empire”. The thinning response to BA was linear, with recommended thinning occurring at 200 mg.1-1. At harvest, fruit weight, size (diameter and length), flesh firmness and soluble solids concentration, chlorophyll and anthocyanin contents, and seed number were increased by BA treatments. BA had no effect on fruit L:D ratio, internal ethylene concentration, maturity, and the onset of the respiratory climacteric, but significantly reduced respiration at harvest. BA also reduced ethylene production and ACC content at harvest, though the reduction was not significant. Although firmness of BA-treated fruit was significantly higher at harvest, upon storage for 1 month at 0-0.5°C and 90-95% RH the firmness advantage was lost BA shows potential as a thinner of “Empire” apple and has advantage of increasing fruit weight and size, since “Empire” is a relatively small apple compared to other commercial cultivars.

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