Studies on the fruit thinning effect of N.A.A. and some carbamates on Jonathan and Delicious apples

1975 ◽  
Vol 15 (74) ◽  
pp. 424
Author(s):  
N Veinbrants
Keyword(s):  
Fruit Set ◽  
Full Bloom ◽  
Time Of Application ◽  
Fruit Thinning ◽  
Bloom Period ◽  
Series Of Experiments ◽  
Thinning Effect

In a series of experiments in Victoria a single spray of the fungicide thiram applied shortly after full bloom reduced fruit density highly significantly on Jonathan and Delicious apples, but resulted in insufficient thinning. The fungicide Dithane M-45 caused mild thinning and the fungicide Dikar had no effect on fruit set when applied during post-bloom period on Jonathan apples. Applications of the insecticide carbamult applied 16, 23 and 32 days after full bloom reduced fruit density highly significantly and to about the extent as N.A.A. applied 16 days after full bloom on Jonathan apples. Carbamult caused the same degree of thinning irrespective of time of application. N.A.A. and carbamult resulted in adequate fruit thinning.

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 Time of metamitron application and concentration in the chemical thinning of ‘Maciel’ peach

2019 ◽  
Vol 41 (4) ◽  
Author(s):  
Roseli de Mello Farias ◽  
Carlos Roberto Martins ◽  
Caroline Farias Barreto ◽  
Marcos Antônio Giovanaz ◽  
Marcelo Barbosa Malgarim ◽  
...  
Keyword(s):  
Fruit Set ◽  
High Efficiency ◽  
Production Costs ◽  
Full Bloom ◽  
Average Mass ◽  
Fruit Abscission ◽  
Different Seasons ◽  
Peach Trees ◽  
Thinning Effect ◽  
Peach Orchard

Abstract In the peach tree cultivation, the producer has the challenge of obtaining good quality fruits and maintaining production in a balanced way over the years. Thinning favors these parameters and reduces the fruit load on plants. Manual thinning commonly practiced on peach trees requires high labor and increases production costs. Chemical thinning as an alternative to manual thinning, which depending on the species, time and concentration, has demonstrated high efficiency. The aim of this study was to evaluate the effect of metamitron applied at different seasons and concentrations on the chemical thinning of peach trees in southern Brazil. Experiments were conducted in a commercial peach orchard (‘Maciel’ cultivar), in the municipality of Morro Redondo, Rio Grande do Sul, Brazil, during the 2015 and 2016 harvests. In experiment 1, metamitron at concentration of 200 mg L-1 was applied at 20, 30, 40, 50 and 60 days after full bloom and manual thinning performed at 40 days after full bloom. In experiment 2, metamitron was applied at concentrations of 100 mg L-1, 200 mg L-1, 300 mg L-1 and 400 mg L-1 and manual thinning at 40 days after full bloom, in addition to control plants. Fruit abscission, fruit set, total number of fruits per plant, yield per plant, average mass and fruit diameter were evaluated. Metamitron at concentration of 200 mg L-1 has thinning effect when applied before 40 days after full bloom. Metamitron concentration of 100 mg L-1 applied at 40 DAFB promoted fruit abscission superior to manual thinning. Therefore, the application of metamitron to ‘Maciel’ peach trees close to full bloom at concentration of 100 mg L-1 results in thinning practice similar to manual 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 Tergitol as a possible thinning agent for peach cv. Redhaven

2014 ◽  
Vol 41 (No. 2) ◽  
pp. 49-54 ◽  
Author(s):  
B. Ambrožič Turk ◽  
N. Fajt ◽  
M. Stopar
Keyword(s):  
Fruit Set ◽  
Fruit Weight ◽  
Size Class ◽  
Full Bloom ◽  
Ammonium Thiosulfate ◽  
South West ◽  
Peach Trees ◽  
Thinning Effect ◽  
Fruit Diameter

The effect of different blossom thinners ammonium thiosulfate (ATS) (1%, 2%), Armothin (1.5%), Tergitol-TMN-6 (0.5%, 1%), applied on peach cv. Redhaven at 50–60% full bloom was evaluated in thinning experiments in south-west Slovenia. The photosynthesis inhibitor metamitron (0.05%) applied at 8 mm fruit diameter was evaluated as fruitlet thinner as well. Application of 2% ATS resulted in excessive thinning. The thinning effect of 1% ATS was also too strong in two out of three thinning experiments. The use of 0.05% metamitron did not cause any thinning effect on peach trees and gave similar results as the non-treated control. The effective fruit set reduction and increase of average fruit weight was achieved with 0.5% and 1% Tergitol application. In three-year experiment both Tergitol applications reduced fruit set toward hand thinned level, but the share of fruit from bigger size class was only once enhanced to the level of hand thinned trees. No sign of phytotoxicity was noticed on fruits in all thinner application treatments.  

Comparison of thiram, carbaryl, N.A.A. and N.A.D. as fruit thinning sprays on Granny Smith apples

1972 ◽  
Vol 12 (54) ◽  
pp. 83 ◽  
Author(s):  
N Veinbrants
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Single Application ◽  
Drastic Reduction ◽  
Full Bloom ◽  
Fruit Thinning ◽  
Wide Range ◽  
Significant Difference

Evidence is presented that a single application of the fungicide thiram at 0.12 per cent, applied 14 and 21 days after full bloom on Granny Smith apples, reduced the fruit set highly significantly, and to about the same extent as carbaryl at 0.02, 0.04, or 0.08 per cent applied 14 days after full bloom. Either material resulted in good fruit thinning. Carbaryl caused about the same degree of thinning over a wide range of concentrations, the only significant difference being between 0.02 and 0.16 per cent (P<0.05). Applications of N.A.D. at 25 p.p.m., and N.A.A. at 5 p.p.m. caused more drastic reduction in fruit set than carbaryl at 0.02, 0.04, and 0.08 per cent, or thiram at 0.12 per cent, applied at the same time. Carbaryl resulted in the most uniform fruit thinning, followed by thiram, N.A.D., and N.A.A. All spray treatments improved fruit size, reduced fluctuations in cropping, and significantly increased fruit yields over a period of four years as compared with unsprayed, hand thinned trees.

scholarly journals `Empire' Apple Responses to Fruit-thinning Chemicals

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 765E-765 ◽  
Author(s):  
Warren C. Stiles
Keyword(s):  
Size Distribution ◽  
Fruit Set ◽  
Total Yield ◽  
Fruit Size ◽  
Diameter Ratio ◽  
Time Of Application ◽  
Fruit Thinning ◽  
Small Fruit

Effects of NAA at 5, 10, and 15 ppm, Accel at 50, 75, and 100 ppm, NAA at 7.5 ppm plus carbaryl at 600 ppm, and a nontreated control on fruit set, fruit size, length–diameter ratio, seed numbers per fruit, and total yield of fruit were evaluated during the 1994 season. All treatments were applied to 10-year-old `Empire'/M.9/MM.111 trees as dilute sprays at a rate of 935 liters·ha–1 with an airblast sprayer on 3 June. King fruit measured 9–11 mm in diameter at time of application. Fruit set (fruits per 100 blossom clusters) was reduced significantly by Accel at 50 ppm (17%) and by NAA plus carbaryl (26%) in comparison with the nontreated control. Total yield of fruit was increased by all treatments; however, fruit from trees treated with NAA plus carbaryl was significantly larger than that from all other treatments. Percentages of small fruit, <108 g, were reduced by all treatments. Percentage of fruit ≥ 153 g was increased significantly only by NAA plus carbaryl. Length–diameter ratios and numbers of fully developed seeds per fruit were not influenced significantly by treatments. NAA at rates of 5, 10, and 15 ppm, or Accel at 50, 75, or 100 ppm, were less effective than a combination of NAA at 7.5 ppm plus carbaryl at 600 ppm in reducing fruit set and in affecting fruit size or fruit size distribution.

Thinning response of ‘Redhaven’ peaches to 1-aminocyclopropane carboxylic acid (ACC)

2020 ◽  
pp. 1-13
Author(s):  
John A. Cline ◽  
Catherine J. Bakker ◽  
Amanda Beneff
Keyword(s):  
Carboxylic Acid ◽  
Fruit Set ◽  
Total Yield ◽  
Fruit Size ◽  
Fruit Weight ◽  
Full Bloom ◽  
Fruit Thinning ◽  
Leaf Yellowing ◽  
Peach Trees ◽  
Fruit Load

Peach trees bear an abundance of flowers which produce a surplus of fruit that the tree is unable to support. A self-regulatory mechanism enhances the abscission of immature fruitlets leading to a reduced fruit load, but this is often insufficient to achieve fruit of marketable size. Supplementary manual fruit thinning is typically required to optimize economic fruit load. This 2-yr study investigated the response of ‘Redhaven’ peach trees to sprays of 300 and 600 mg L−1 1-aminocyclopropane carboxylic acid (ACC) during the phenological stages of full bloom, shuck split, and ∼20 mm fruitlet diameter. The objective was to determine the efficacy of ACC on fruit set, fruit size, and yield at harvest and the amount of hand-thinning required at “June drop”. Although the response to ACC varied between the 2 yr, 600 mg L−1 ACC spray at full bloom (2018) and at ∼20 mm fruit size (2019) reduced fruit set, the need for hand-thinning by 59%–66%, and crop load. Treatments also had varying but significant effects on leaf yellowing and leaf drop when measured shortly after application. ACC reduced total yield and number of fruit per tree in both study years and increased fruit weight in 2019. Overall, peaches were responsive to ACC at a range of timings from bloom to ∼20 mm fruit size. This study enhances our understanding of ACC on fruitlet abscission of peaches and is one of few studies to demonstrate the effectiveness of a chemical fruitlet thinner for peaches.

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.

scholarly journals Chemical Fruit Thinning with Armothin® Sprays to Reduce Fruit Set in `Loadel' Cling Peach

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 854B-854
Author(s):  
Stephen M. Southwick ◽  
James T. Yeager
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Stone Fruit ◽  
Full Bloom ◽  
Akzo Nobel ◽  
Fruit Thinning ◽  
Spray Volume ◽  
Experimental Use

Hand-thinning is required every season to ensure large fruit size of `Loadel' cling peach in California. Hand-thinning is costly. Chemical thinning could help to lower costs of hand-thinning. Armothin® {[N,N-bis2-(omega-hydroxypolyoxyethylene/polyoxypropylene)ethyl alkylamine], AKZO-Nobel, Inc., Chicago; AR} was sprayed at 80% of full bloom (FB), FB and FB + 3 days. The spray volume was 935 liters·ha–1. Concentrations of AR were 1%, 3%, and 5% AR applied at FB. No damage to fruit was noted. Leaf and fine shoot phytotoxicity were seen at 5% AR. The amount of time needed and number of fruits thinned were reduced by those same treatments. Salable yield and fruit size after AR treatments equaled those found on hand-thinned controls. Armothin® shows promise for chemical thinning of peach when used as a bloom spray that damages flowers, thereby reducing fruit set. An experimental use permit was issued for use of AR for stone fruit thinning in California during 1995.

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