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 EFFECTS OF HYDROGEN CYANAMIDE ON APPLE AND PLUM FRUIT THINNING

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 690a-690
Author(s):  
Esmaeil Fallahi ◽  
Brenda R. Simons ◽  
John K. Fellman ◽  
W. Michael Colt
Keyword(s):  
Malus Domestica ◽  
Fruit Set ◽  
Fruit Size ◽  
Apple Fruit ◽  
Fruit Weight ◽  
Full Bloom ◽  
Hydrogen Cyanamide ◽  
Fruit Thinning ◽  
Prunus Salicina

Influence of various concentrations of hydrogen cyanamide (HC) on fruit thinning of `Rome Beauty' apple (Malus domestica Borkh.), `Friar,' and `Simka' plums (Prunus salicina Lindley) were studied. A full bloom application of HC at all tested concentrations decreased `Rome Beauty' apple fruit set and yield, and increased fruit weight. Hydrogen cyanamide at 0.25% (V/V) resulted in adequate apple thinning, indicated by the production of an ideal fruit weight. Prebloom and full bloom applications of HC at greater than 0.75% reduced plum fruit set and yield in `Friar.' Full bloom application of HC at 0.25% to 0.50% showed a satisfactory fruit set, yield, and fruit size in `Friar' plum. Full bloom application decreased fruit set and yield in `Simka' plum. Hand thinning, as well as chemical thinning, is recommended for plums.

scholarly journals EFFECTS OF HYDROGEN CYANAMIDE ON STONE FRUIT THINNING

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1122a-1122
Author(s):  
Esmaeil Fallahi ◽  
Michael Colt ◽  
S. Krishna Mohan ◽  
John Fellman
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Stone Fruit ◽  
Severe Toxicity ◽  
Full Bloom ◽  
Hydrogen Cyanamide ◽  
Fruit Number ◽  
Fruit Thinning

Influence of prebloom and full bloom applications of hydrogen cyanamide on `Simka' and `Friar' plums in Southwest Idaho and `Florda Prince' peach in Southwest Arizona was studied. Prebloom application of 0.5% hydrogen cyanamide caused severe toxicity to the fruit buds in `Friar' lure, while 2% hydrogen cyanamide did not cause toxicity in `Simka' plum. `Simka' fruit was effectively thinned with 1-2% prebloom application. At full bloom, 1.5% hydrogen cyanamide caused severe flower and leaf burning in both `Friar' and `Simka' plums, while concentrations between 0.1% and 1% thinned flowers (fruits) in both of the plum cultivars. Influence of hydrogen cyanamide on final fruit set, fruit size and maturity are also studied. Prebloom or full bloom applications of 2% or 3% hydrogen cyanamide eliminated 95 to 100% of the blooms, while application of this chemical at 1% sufficiently thinned the fruit. Number of commercially packed large peaches in trees receiving 1% hydrogen cyanamide was the same as that in trees thinned by hand, suggesting hydrogen cyanamide as a potential chemical for stone fruit thinning.

scholarly journals 186 INFLUENCE OF HYDROGEN CYANAMIDE AND WILTH IN ON BLOSSOM THINNING OF APPLE AND PLUM

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 455f-455
Author(s):  
Esmaeil Fallahi ◽  
Brenda R. Simons ◽  
Max W. Williams
Keyword(s):  
Fruit Quality ◽  
Fruit Set ◽  
Fruit Size ◽  
Soluble Solids ◽  
Full Bloom ◽  
Mature Trees ◽  
Hydrogen Cyanamide ◽  
Fruit Thinning ◽  
Yield And Quality

Effects of hydrogen cyanamide and Wilthin on blossom thinning and the consequences of thinning on fruit set, yield and fruit quality of `Rome Beauty' was studied. A full bloom application of hydrogen cyanamide at the rate of 0.25% (Dormex formulation) or 0.25% of Wilthin both followed by a fruit thinning by Sevin + NAA effectively thinned mature trees of `Rome Beauty' and had a similar effect on fruit set, yield and fruit quality. The effects of these two chemicals at these rates on several aspects of fruit set, yield and quality were similar to the effects of Elgetol. Hydrogen cyanamide, Elgetol and 0.25% Wilthin at full bloom resulted in a higher percentage of single fruit set, thus, less labor for hand thinning. Application of 0.37% Wilthin at 20% bloom or at full bloom resulted in larger fruit size, but induced fruit russetting. Soluble solids of fruit from trees with Elgetol, 0.37% Wilthin at 20% bloom or at full bloom were higher than fruit from other treatments. Hydrogen cyanamide at 0.50% resulted in a satisfactory level of blossom thinning in `Friar' plums.

scholarly journals Chemically Thinning Spur `Delicious' Apples with Carbaryl, NAA, and Ethephon at Various Stages of Fruit Development

1996 ◽  
Vol 6 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Richard P. Marini
Keyword(s):  
Acetic Acid ◽  
Fruit Development ◽  
Fruit Set ◽  
Naphthalene Acetic Acid ◽  
Full Bloom ◽  
Fruit Thinning ◽  
Repeated Applications ◽  
Fruit Diameter

Chemical fruit thinners were applied to limbs or whole trees of spur `Delicious' at various stages of fruit development as indicated by fruit diameter. Carbaryl, naphthalene acetic acid (NAA), and ethephon all reduced fruit set when applied at a fruit diameter of ≈4 to 15 mm. Fruit thinning for NAA and carbaryl, alone or combined, generally was greater when applied at an average fruit diameter of 8 mm, rather than at 4 mm. Repeated applications of NAA or carbaryl were no more effective than single applications. NAA + carbaryl applied at 9 mm was more effective than NAA applied at 4 mm followed by carbaryl at 8 mm. Applied when fruit diameter averaged 17 to 22 mm, ethephon and ethephon + carbaryl were effective fruit thinners. When applied at full bloom to ≈10 and 20 mm, the insecticides ethion and oxamyl, respectively, were effective fruit thinners.

scholarly journals Heading Fruiting Shoots before Bloom Is Equally Effective as Blossom Removal in Peach Crop Load Management

HortScience ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 642-646 ◽  
Author(s):  
Richard P. Marini
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Fruit Weight ◽  
Load Management ◽  
Full Bloom ◽  
Crop Load ◽  
Fruit Thinning ◽  
Crop Density ◽  
Net Profit

Three experiments were performed to determine if pruning treatments could reduce the need for peach [Prunus persica (L.) Batsch] fruit thinning without reducing average fruit weight. To determine if dormant shoot heading affected fruit size simply by reducing the number of flowers per tree, all 1-year-old shoots on `Cresthaven' trees were headed by 50% or blossoms were removed from the terminal half of each shoot. At 45 days after full bloom, all trees were hand-thinned to obtain predetermined crop densities. Average fruit weight was highest on trees with blossom removal, but crop value and net profit were highest for nontreated trees. To determine the influence of treatment severity on fruit weight, all shoots on `Cresthaven' trees were blossom-thinned or headed to remove blossoms on varying proportions of each shoot. Fruit set and the number of fruit removed during postbloom thinning decreased as the percentage of a shoot that was headed or blossom-thinned increased. Average fruit weight at harvest and crop value were higher for trees with blossom removal than for trees with headed shoots. Fruit weight and crop value were not affected by the percentage of the shoot treated. In the final experiment, all shoots on `Cresthaven' trees were headed by 50% or were not headed. Heading of shoots reduced fruit set, number of fruits removed at thinning, and thinning time per tree, but yield, crop density, and average fruit weight were not affected by heading. Profit was increased by shoot heading one of the 3 years. Results from this study indicate that heading peach shoots by 50% while dormant pruning can reduce thinning costs without reducing fruit size, but a similar level of labor-intensive blossom removal may reduce postbloom thinning costs and improve 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.

scholarly journals Heading of shoots and hand thinning of flowers and fruits on 'BRS Kampai' peach trees

2017 ◽  
Vol 52 (11) ◽  
pp. 1006-1016 ◽  
Author(s):  
Paula Duarte de Oliveira ◽  
Gilmar Arduino Bettio Marodin ◽  
Gustavo Klamer de Almeida ◽  
Mateus Pereira Gonzatto ◽  
Daniel Chamorro Darde
Keyword(s):  
High Frequency ◽  
Prunus Persica ◽  
Fruit Size ◽  
Fruit Production ◽  
No Production ◽  
Full Bloom ◽  
Fruit Thinning ◽  
Heading Control ◽  
Peach Trees

Abstract: The objective of this work was to evaluate the effect of shoot heading and of hand thinning in different development stages of flowers and fruits on the fruit production and quality of 'BRS Kampai' peach (Prunus persica) trees. The experiment was performed during three crop years, under the conditions of the “Depressão Central” region in the state of Rio Grande do Sul, Brazil, and the treatments were: T1, heading of half of the mixed shoot; T2, heading of one third of the mixed shoot; T3, flower thinning in the pink bud stage; T4, thinning at full bloom; T5, thinning of fruit with 5 mm; T6, thinning of fruit with 20 mm; and T7, no thinning or heading (control). Fruit production and quality were evaluated. Plants with no thinning were more productive, but showed high frequency of fruits with a diameter smaller than 60 mm. Shoot heading reduced production per tree and resulted in small-sized fruit. Thinning time did not affect production, and fruit size was greater when thinning was performed at the bloom stage. 'BRS Kampai' peach trees can be thinned starting at bloom, which provides greater fruit size, with no production loss.

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.

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 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.

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