THINNING SPARTAN APPLES WITH CARBARYL AND 1-NAPHTHALENEACETIC ACID: INFLUENCE OF SPRAY VOLUME AND COMBINATIONS OF CHEMICALS

1984 ◽  
Vol 64 (1) ◽  
pp. 161-166 ◽  
Author(s):  
N. E. LOONEY ◽  
J. E. McKELLAR
Keyword(s):  
Malus Domestica ◽  
Fruit Set ◽  
Analysis Of Covariance ◽  
Naphthaleneacetic Acid ◽  
Full Bloom ◽  
Cross Sectional ◽  
Fruit Thinning ◽  
Main Effect ◽  
Spray Volume ◽  
Flowering Intensity

In three of four experiments conducted between 1979 and 1981, significantly better fruit thinning of Spartan apple (Malus domestica Borkh.) was achieved with 1-naphthaleneacetic acid (NAA) (17–34 g/ha) tank-mixed with carbaryl (1.67–2.25 kg/ha) than with either chemical applied singly. NAA usually thinned more effectively than carbaryl. Spray volume (from 560 to 4400 L/ha) was not a major factor influencing the thinning result but in the two experiments where it was a significant main effect, better thinning was achieved with reduced spray volume. Sprays applied at 15 days after full bloom were more effective than those applied at 25 days. In three experiments, the number of blossom clusters per unit of branch cross-sectional area (’flowering intensity’) was a highly significant covariate with proportionally fewer fruits setting when flowering intensity was high. Therefore, an analysis of covariance permitted better resolution of the spray treatment effects.Key words: Chemical thinning, fruit set, Malus domestica

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 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.

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 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 Removal of the Most Developed Flowers Influences Fruit Set, Quality, and Yield of Apple Clusters

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 353-356 ◽  
Author(s):  
Carlos Miranda ◽  
Luis G. Santesteban ◽  
José B. Royo
Keyword(s):  
Malus Domestica ◽  
Fruit Set ◽  
Growth Potential ◽  
Analysis Of Covariance ◽  
Wide Range ◽  
Golden Delicious ◽  
Flower Density ◽  
Apple Cultivars ◽  
Made In

The apical or king (K) flower in the apple (Malus ×domestica L. Borkh.) cluster usually develops and blooms first and also has a greater sink potential. For this reason, resources are primarily used by the K fruit, and this is also one of the reasons why most thinning practices tend to favor K fruit set. However, it is not always possible to retain the K flower and remove the lateral ones. This study was undertaken to determine if the removal of the most developed flowers in the cluster influences yield or quality compared to that obtained in a whole cluster. The treatments were made in `Golden Delicious' and `Royal Gala' apple cultivars, within a wide range of flower densities for each cultivar. The factor tested was the intensity of flower removal (FRI); the treatments consisted in removing one, two, or three flowers in each cluster. Flower density was used as a covariate in an analysis of covariance to account for differences in flower densities in response to FRI treatments. In all experiments the covariate was not significant; therefore FRI effect was not affected by flower density. `Golden Delicious' and `Royal Gala' had similar responses to flower removal, so that when at least three flowers in a cluster remained, fruit set and cluster yield were similar to whole clusters. Only when two or fewer poorly developed flowers remained after FRI treatments, yield was reduced by as much as 25%. Fruit from FRI clusters were even heavier than those from whole clusters, due to reduced competition among the fruit, so that the growth potential of fruit from the first and second lateral flowers was similar to clusters with K fruit, in clusters where the K flower had been removed.

scholarly journals 657 Relationship between Intensity of Flowering and Cropping in Fruit and Nuts

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 561C-561
Author(s):  
E.W. Stover
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Commercial Application ◽  
Critical Periods ◽  
Alternate Bearing ◽  
Crop Species ◽  
Fruit Thinning ◽  
Small Fruit ◽  
Substantial Investment ◽  
Flowering Intensity

The relationship between intensity of flowering and various aspects of cropping will be reviewed for fruit and nuts. Clearly, relatively light flowering can limit yield in most fruit and nut species. This commonly occurs before mature bearing commences and in “off” years for varieties that display alternate bearing. During mature bearing, many species will carry fruit numbers that exceed commercially desired levels, resulting in excessively small fruit and accentuating alternate bearing. The economic disadvantages of excess cropload have resulted in considerable research on fruit thinning and widespread commercial application of this practice. Heavy flowering intensity in some crop species results in economic disadvantages beyond the problems of excessive cropload and resultant small fruit size. Many species flower profusely and have initial fruit set far in excess of final tree capacity, resulting in abscission of numerous flowers and fruitlets. Abscised organs can represent a substantial investment in carbohydrates and nutrients, compromising availability at critical periods in flower and fruit development. The potential implications of this process are best exemplified in navel orange, where an increase in flowering beyond intermediate intensity results in a reduction in both initial fruit set and final fruit yield at harvest. In several crops, there is evidence that fruit size may be reduced by excessive flowering, even when cropload is quickly adjusted to an acceptable level. These data suggest that further research on the advantages of controlling flowering intensity is warranted.

scholarly journals Influence of Blossom and Fruit Thinning on Peach Flower Bud Tolerance to an Early Spring Freeze

HortScience ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 146-148 ◽  
Author(s):  
Ross E. Byers ◽  
R.P. Marini
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
Unit Length ◽  
Early Spring ◽  
Late Winter ◽  
Flower Buds ◽  
Flower Bud ◽  
Cross Sectional ◽  
Fruit Thinning ◽  
Crop Density

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.

Fruit thinning using NAA shows potential for reducing biennial bearing of 'Barnea' and 'Picual' oil olive trees

2009 ◽  
Vol 60 (12) ◽  
pp. 1124 ◽  
Author(s):  
Arnon Dag ◽  
Amnon Bustan ◽  
Avishai Avni ◽  
Shimon Lavee ◽  
Joseph Riov
Keyword(s):  
Production Systems ◽  
Fruit Size ◽  
Naphthaleneacetic Acid ◽  
Full Bloom ◽  
Biennial Bearing ◽  
Fruit Thinning ◽  
Dynamic Relationship ◽  
Primary Determinant ◽  
Olive Cultivars ◽  
Fruit Load

Biennial bearing is a major horticultural and economic drawback of olive (Olea europaea L.) cultivation, which particularly affects the olive oil industry under intensive production systems. The number of fruits per tree in an on-year is a primary determinant of the biennial cycle. While fruit thinning using NAA shortly after full bloom is commonly practiced to increase fruit size in table olives, the extent of its influence on biennial bearing is unknown. In the present study, the ability of that common naphthaleneacetic acid (NAA) treatment (100 mg/L, 10 days after full bloom) to alleviate biennial bearing in two oil olive cultivars, Picual and Barnea, was poor, although significant influence on the number of fruit was evident solely in Barnea. Picual seemed less susceptible than Barnea to biennial bearing. Consequently, the effect of a broad range of NAA concentrations (0–320 mg/L, 10 days after full bloom) on various yield parameters was investigated during a biennial cycle of Barnea trees. There was a gradual proportional decline in the on-year number of fruits from ~50 000 to 10 000/tree in response to increasing NAA concentrations. The number of return fruits in the off-year was reciprocal to the on-year fruit load, but remained relatively small, below 15 000/tree. The dynamic relationship between fruit load and fruit size in both on- and off-years was a significant compensation factor in fruit and oil yields. In both cultivars, an on-year fruit load smaller than 20 000/tree is likely to provide consistent yearly oil yields ranging from 10 to 12 kg/tree. The results demonstrate the possibility of using NAA post-bloom spraying to balance biennial bearing in oil olives.

scholarly journals Storage Responses of `Empire' Apples to Benzyladenine and Other Chemical Thinners

1994 ◽  
Vol 119 (2) ◽  
pp. 253-257 ◽  
Author(s):  
D.C. Elfving ◽  
E.C. Lougheed
Keyword(s):  
Malus Domestica ◽  
Soluble Solids ◽  
Starch Hydrolysis ◽  
Naphthaleneacetic Acid ◽  
Full Bloom ◽  
Ethylene Evolution ◽  
Flesh Firmness

In three trials over 3 years, foliar BA applications for fruitlet thinning of `Empire' apple (Malus domestica Borkh.) trees produced small and inconsistent effects on flesh firmness at harvest and after air storage. Soluble solids concentrations at harvest and after air storage were consistently increased by BA alone or together with GA4+7 [Promalin (PR)], and were also increased by CB in one trial. Starch hydrolysis was slightly delayed by BA applications in 1990. Ethylene evolution at harvest was increased by NAA in 1988 and slightly increased by PR applied 29 days after full bloom (DAFB) in 1990, while poststorage ethylene evolution was stimulated by BA and PR treatments in 1990 except BA at 29 DAFB. Incidence of poststorage disorders was low and largely uninfluenced by thinning treatments. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine [benzyladenine (BA)]; BA plus gibberellins A4 and A7 (GA 4+7) [Promalin (PR)]; 1-naphthaleneacetic acid (NAA); 1-naphthalenyl methylcarbamate [carbaryl (CB)].

scholarly journals EFFECT OF ROOT PRUNING AND CHEMICAL THINNING ON GROWTH AND FRUITING OF `McINTOSH' APPLE TREES.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1153b-1153
Author(s):  
James R. Schupp ◽  
Highmoor Farm
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Shoot Length ◽  
Root Pruning ◽  
Full Bloom ◽  
Apple Trees ◽  
Cross Sectional ◽  
Fruit Drop ◽  
Napthaleneacetic Acid ◽  
Fruit Diameter

Mature `McIntosh'/MM.111 apple (Malus domestica, Borkh.) trees were treated to evaluate the response of root pruned trees to chemical thinning and to determine if reducing the crop load increased fruit size on root pruned trees. The trees were root pruned at full bloom in 1988 and 1989, by cutting on both sides of the row 1m from the trunk and 30cm deep. Water, 600mg/liter carbaryl, 5mg/liter napthaleneacetic acid (NAA), or NAA plus carbaryl were applied when fruit diameter was approximately 10mm. Trunk cross-sectional area (TCSA) was increased by thinning treatments in 1988, but root pruning had no effect. In 1989, root pruning reduced TCSA increment by 35%. Shoot length was reduced by root pruning both years. All treatments reduced percent fruit set in 1989, however root pruned trees and trees treated with NAA had the highest fruit numbers at harvest. Preharvest fruit drop was reduced by root pruning in both 1988 and 1989. Root pruning had no influence on the response of apple trees to chemical thinning. Removing a portion of the crop with chemical thinners was partially successful in counteracting the reduction in fruit size caused by root pruning.

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