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.

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.

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.

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.

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 APPLE FRUIT CHEMICAL THINNING IN CHIHUAHUA, MÉXICO

2008 ◽  
Vol 31 (3) ◽  
pp. 243
Author(s):  
David I. Berlanga-Reyes ◽  
Alejandro Romo-Chacón ◽  
Ángel R. Martínez-Campos ◽  
Víctor M. Guerrero-Prieto
Keyword(s):  
Fish Oil ◽  
Fruit Set ◽  
Fruit Size ◽  
Apple Fruit ◽  
Naphthalene Acetic Acid ◽  
Alternate Bearing ◽  
Fruit Thinning ◽  
Equatorial Diameter ◽  
Large Trees ◽  
Golden Delicious

Chemical fruit thinning is a common practice in apple (Malus x domestica Borkh.) orchards for achieving high quality fruits, reduced costs of hand-thinning and promote return of flowering. Hand thinning is a common and high cost practice, not only due to the labor involved, but also because seedling and vigorous clonal rootstocks result in large trees. The chemical thinning agents: Ethephon (ETH), Carbaryl (CB), Naphthalene acetic acid (NAA), 6- Benzyladenine (6-BA), and fish oil were evaluated on ‘Golden Delicious’ and ‘RedChief Delicious’ apple trees in 2004 and 2005. Chemical thinning effect was compared with early and late handthinnings. Treatments were sprayed when the biggest fruit in the clusters was 10 mm in equatorial diameter. NAA showed the best effect in reducing final fruit set in both cultivars and years evaluated, with results comparable to those of early hand-thinning (thinned when king-fruit size was 10 mm) in ‘Golden Delicious’ trees. In ‘RedChief Delicious’, fruit set reduction by NAA, fish oil and CB treatments was similar to early hand-thinned trees only in 2005. In 2005, time spent during supplementary hand-thinning in ‘Golden Delicious’ trees was reduced by chemical thinning treatments, except by fish oil; whereas in ‘RedChief Delicious’ only NAA K-salt reduced it in 2004. An increase in fruit equatorial diameter was observed only in 2004 with NAA and fish oil. Alternate bearing, typical of ‘Golden Delicious’, was not diminished by these chemical thinning treatments.

Effect of timing of hand thinning on the cropping potential of Red Fuji apple trees

1992 ◽  
Vol 32 (3) ◽  
pp. 417 ◽  
Author(s):  
KM Jones ◽  
SA Bound ◽  
TB Koen ◽  
MJ Oakford
Keyword(s):  
Strong Correlation ◽  
Fruit Size ◽  
Research Station ◽  
Full Bloom ◽  
Apple Trees ◽  
Fruit Crop ◽  
Golden Delicious ◽  
Fuji Apple

In a hand-thinning trial of 6-year-old Red Fuji apple trees on seedling rootstocks at the Grove Research Station in southern Tasmania, unthinned controls were compared with trees that were hand-thinned between full bloom and 56 days after full bloom. Trees were thinned to about 200 flowers or fruit per tree. The response of fruit size and weight to later thinning was negative and linear (R2=0.72). This regression was not significantly affected if adjusted for the varying fruit crop per tree. It is concluded that in Australia, Red Fuji is capable of producing larger fruit at higher crop loads than either Red Delicious or Golden Delicious and that thinning at blossom produces much larger fruit than later thinning. Because of the strong correlation between Red Fuji fruit size or weight and time of thinning, we conclude that it is preferable to thin at blossom time.

scholarly journals GROWTH, YIELD AND POSTHARVEST QUALITY OF WAX APPLE AS AFFECTED BY NAPHTHALENE ACETIC ACID APPLICATION

2015 ◽  
Vol 37 (2) ◽  
pp. 410-422
Author(s):  
MOHAMMAD MONERUZZAMAN KHANDAKER ◽  
ABM SHARIF HOSSAIN ◽  
NORMANIZA OSMAN ◽  
NASHRIYAH MAT ◽  
AMRU NASRULHAQ BOYCE
Keyword(s):  
Acetic Acid ◽  
Fruit Size ◽  
Growth Yield ◽  
Fruit Growth ◽  
Field Conditions ◽  
Soluble Solids ◽  
Growth And Yield ◽  
Postharvest Quality ◽  
Naphthalene Acetic Acid

Results of this study represent the first report of the effect of Naphthalene Acetic Acid (NAA) on the pre and post harvest quality of wax apple fruit. The wax apple trees were spray treated with 0, 5, 10 and 20 mg L-1 NAA under field conditions during 2008 to 2011. The experiments were carried out in Completely Randomized Design (CRD) with six replications. Leaf chlorophyll content, chlorophyll fluorescence, photosynthetic yield, net photosynthetic rate, drymatter content of leaves and total soluble solids and K+content of wax apple fruits were significantly increased after treatments with 10 mg L-1. Polygalacturonase activity significantly decreased with NAA treatments. The application of 5 mg L-1 NAA increased 27% more bud and reduced 42% less fruit drop compared to the control. In addition, higher protein and phosphate synthase activity of leaves, fruit set, fruit growth, larger fruit size and yield were recorded in NAA treated plants. In storage, treated fruits exhibited higher TSS and firmness and less weight loss, browning, titratable acidity, respiration and ethylene production than the control. It is concluded that spraying with 5 and 10 mg L-1 NAA once a week under field conditions produced better fruit growth and yield of the wax apple and maintained better fruit quality in postharvest storage.

Role of naphthalene acetic acid and phenothiol treatments on increasing fruit size and advancing fruit maturity in loquat

2004 ◽  
Vol 101 (4) ◽  
pp. 387-398 ◽  
Author(s):  
A. Amorós ◽  
P. Zapata ◽  
M.T. Pretel ◽  
M.A. Botella ◽  
M.S. Almansa ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Fruit Size ◽  
Naphthalene Acetic Acid ◽  
Fruit Maturity

scholarly journals FOLIAR APPLICATION OF BENZYLADENINE INCREASES ENDOGENOUS LEAF CYTOKININ IN APPLE

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 480d-480 ◽  
Author(s):  
Robin A. Cohen ◽  
Duane W. Greene
Keyword(s):  
Growth Regulator ◽  
Foliar Application ◽  
Foliar Spray ◽  
Application Rate ◽  
Endogenous Cytokinin ◽  
Full Bloom ◽  
Apple Leaves ◽  
Golden Delicious

Two experiments were conducted to examine the effects of growth regulator application on cytokinin levels in developing apple leaves. In experiment 1, gibberellin GA4/7 (100 mg·liter-1) and benzyladenine (BA, 100 mg·liter-1) were applied alone or in combination as a foliar spray to `Golden Delicious' 7 days after full bloom. In experiment 2, BA was applied at 50 or 100 mg·liter-1 as a foliar spray to `Morespur McIntosh' 18 days after full bloom. Trans-zeatin ribosidelike (t-ZR) levels were determined by immunoassay. In experiment 1, GA1/7 had no effect and BA increased t-ZR-like levels. In experiment 2, BA increased t-ZR levels quadratically with application rate. The increase in endogenous cytokinin levels with BA treatment occured within 2 hours. Initially, t-ZR-like levels were 47 times higher in the BA (100 mg·liter-1) treated leaves as compared to check leaves. Over the next 8 days, t-ZR-like content in treated leaves decreased in a cubic manner.

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.

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