Use of airshear technology to reduce chemical spray rates for thinning of apples

1995 ◽  
Vol 35 (6) ◽  
pp. 789 ◽  
Author(s):  
MJ Oakford ◽  
SA Bound ◽  
KM Jones ◽  
L O'Rielly
Keyword(s):  
High Volume ◽  
Fruit Weight ◽  
Research Station ◽  
Full Bloom ◽  
Chemical Application ◽  
Apple Industry ◽  
Industry Standard ◽  
Application Rates ◽  
Chemical Spray ◽  
Polynomial Models

An experiment at the Grove Research Station in southern Tasmania compared the efficacy of low spray volume (LV) treatments of NAA applied by an airshear sprayer with that of the industry standard, airblast sprayer, high volume (HV) application of 4000 L/ha at 10 mg NAA/L to thin Red Delicious apple trees. By adjusting the concentration of NAA, the LV treatments of 100, 200, 400, and 800 L/ha were each applied at 4 rates of NAA representing 25, 50, 75, and 100% of the HV rate of 40000 mg/ha. All treatments were applied at full bloom and 9 days after full bloom. All chemical rates except 25% reduced crop load significantly compared with the control. Fruit weight and size improved in most cases at the 100, 75, and 50% chemical rates. Fruit numbers and mean fruit weight were fitted to polynomial models. This work shows that airshear technology is effective at volumes as low as 100 L/ha, which represents a major saving in spraying time. It also indicates that with effective spraying systems, chemical application rates can be reduced to 50-75% of label rates. This should give the apple industry the confidence to reduce rates and still produce crops of high quality fruit.

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.

Reducing spray volumes and dosages on conventional airblast orchard sprayers using low volume nozzle systems

1997 ◽  
Vol 37 (5) ◽  
pp. 591 ◽  
Author(s):  
S. A. Bound ◽  
M. J. Oakford ◽  
K. M. Jones
Keyword(s):  
High Volume ◽  
Research Station ◽  
Spray Drift ◽  
Spray Application ◽  
Hollow Cone ◽  
Full Bloom ◽  
Chemical Treatments ◽  
Fine Droplet ◽  
Low Volume ◽  
Chemical Usage

Summary.Low volume, fine-droplet hollow cone (HC) Delavan nozzles were fitted to a conventional airblast machine in an attempt to reduce both the volume of spray and the dosage of chemical to thin apples. Red ‘Delicious’ trees at the Grove Research Station in southern Tasmania were thinned with ethephon at full bloom and the post-bloom thinner 6-benzyladenine at 20 days after full bloom. An unthinned control was compared with a treatment hand-thinned at 20 days after full bloom and chemically thinned treatments. The chemical sprays were applied with an airblast sprayer at high volume using conventional nozzles or Delavan HC nozzles at 50, 100, 200, 400 or 800 L/ha at 50, 75 or 100% of the dosage used at high volume. Most chemical treatments had some effect on the parameters measured when compared with the unthinned control while some were as effective as the hand-thinned treatment. The most consistent treatments were at 200 L/ha at the 75 and 100% dosages. Higher or lower volumes tended to be less effective, however, this could have been caused by either spray drift or evaporation of the smaller droplets used at these volumes. Although reducing the dosage to 75% did not reduce thinning effects, reduction of dosage to 50% resulted in significantly less thinning. These results offer a breakthrough for many orchardists to convert to low volume spray application very economically using the Delavan HC nozzles which produce a better droplet size than traditional high volume hydraulic nozzles. It also offers possibilities to significantly lower chemical usage by reducing dosage of chemical applied per hectare. Even more important is the reduction of wastage and pollution.

scholarly journals Almond Fruit Drop Patterns under Mediterranean Conditions

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 544
Author(s):  
Jaume Lordan ◽  
Lourdes Zazurca ◽  
Mercè Rovira ◽  
Laura Torguet ◽  
Ignasi Batlle ◽  
...  
Keyword(s):  
Fruit Set ◽  
Growing Season ◽  
Fruit Weight ◽  
Key Factors ◽  
Full Bloom ◽  
Tree Management ◽  
Fruit Drop ◽  
Mediterranean Conditions ◽  
New Cultivars ◽  
Scion Cultivar

Almond is an important tree nut crop worldwide, and planted areas have been increasing year after year. While self-fertility is one of the key factors when it comes to improved almond productivity of new cultivars, yield is also affected by the number of flowers produced, pollination, fruit set, fruit drop, and fruit weight. Almond fruit drop patterns of 20 Mediterranean almond cultivars were studied over three years. In addition, fruit drop patterns of two scion cultivars ‘Marinada’ and ‘Vairo’ budded onto eight to 10 different rootstocks managed with three different pruning strategies were studied for two years. Cumulative flower and fruit drop ranged from 50% to 90% among cultivars and treatments, and there were up to four fruit drop events during the growing season, the main one occurring from 20–60 days from full bloom (DFFB). Subsequent drops were at 100 DFFB, 120–140 DFFB, and the last one at 160–180 DFFB. The later drops were less apparent. In general, about half of the cumulative drop was comprised of buds and flowers, and the remaining percentage was fruit that dropped 20 or more days after full bloom. Furthermore, different fruit drop patterns were observed depending on the cultivar. For late- and extra-late flowering cultivars, cumulative fruit drop began to decrease earlier, with most of the drops occurred already at full bloom, whereas the opposite was observed for the early flowering cultivars. Rootstocks also had an important effect on the fruit drop pattern, with different effects depending on the scion cultivar. Tree management, such as type of pruning, also had an important effect on the rate of fruit drop and cumulative drop. Therefore, each combination of cultivar × rootstock × pruning type will require different strategies in order to reduce the fruit drop and optimize crop loads.

scholarly journals EARLY SPRING APPLICATION OF AMINOETHOXYVINILGLYCINE (AVG) INCREASES FRUIT SET AND YIELD OF ‘ROCHA’ PEARS

2017 ◽  
Vol 39 (4) ◽  
Author(s):  
MATEUS DA SILVEIRA PASA ◽  
BRUNO CARRA ◽  
CARINA PEREIRA DA SILVA ◽  
MARLISE NARA CIOTTA ◽  
ALBERTO FONTANELLA BRIGHENTI ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Fruit Set ◽  
Block Design ◽  
Quality Attributes ◽  
Fruit Weight ◽  
Early Spring ◽  
Full Bloom ◽  
Growing Seasons ◽  
Randomized Block Design ◽  
Return Bloom

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. Ethylene is associated with abscission of flowers and fruitlets. Then, the application of ethylene synthesis inhibitors, such as AVG, is a potential tool to increase fruit set of pears. The objective of this study was to evaluate the effect of AVG, sprayed at different rates and timings, on fruit set, yield and fruit quality of ‘Rocha’ pear. The study was performed in a commercial orchard located in the municipality of São Joaquim, SC, during the growing seasons of 2014/2015 and 2015/2016. Plant material consisted of ‘Rocha’ pear trees grafted on quince rootstock ‘BA29’. AVG was tested at different rates (60 mg L-1 and 80 mg L-1) and timings [full bloom, one week after full bloom (WAFB), and two WAFB), either alone or in combination. The experiment was arranged in a randomized block design, with at least five single-tree replications. The fruit set, number of fruit per tree, yield, estimated yield, fruit weight, return bloom, and fruit quality attributes were assessed. Fruit set and yield were consistently increased by single applications of AVG at 60 and 80 mg L-1 at both one and two weeks after full bloom, without negatively affecting fruit quality attributes and return bloom.

scholarly journals Rootstock Effects on Growth, Cell Number, and Cell Size of `Gala' Apples

2004 ◽  
Vol 129 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Yahya K. Al-Hinai ◽  
Teryl R. Roper
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Agricultural Research ◽  
Fruit Size ◽  
Cell Number ◽  
Fruit Growth ◽  
Research Station ◽  
Full Bloom ◽  
Final Size ◽  
Load Effects

The effects of rootstock on growth of fruit cell number and size of `Gala' apple trees (Malus domestica Borkh) were investigated over three consecutive seasons (2000-02) growing on Malling 26 (M.26), Ottawa-3, Pajam-1, and Vineland (V)-605 rootstocks at the Peninsular Agricultural Research Station near Sturgeon Bay, WI. Fruit growth as a function of cell division and expansion was monitored from full bloom until harvest using scanning electron microscopy (SEM). Cell count and cell size measurements showed that rootstock had no affect on fruit growth and final size even when crop load effects were removed. Cell division ceased about 5 to 6 weeks after full bloom (WAFB) followed by cell expansion. Fruit size was positively correlated (r2 = 0.85) with cell size, suggesting that differences in fruit size were primarily a result of changes in cell size rather than cell number or intercellular space (IS).

scholarly journals Flower thinning of apple cultivar Braeburn using ammonium and potassium thiosulfate: Short communication

2011 ◽  
Vol 38 (No. 3) ◽  
pp. 120-124 ◽  
Author(s):  
B. Milić ◽  
N. Magazin ◽  
Z. Keserović ◽  
M. Dorić
Keyword(s):  
Titratable Acidity ◽  
Fruit Shape ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Leaf Damage ◽  
Starch Degradation ◽  
Full Bloom ◽  
Flower Bud ◽  
Flower Bud Formation ◽  
Flower Thinning

Ammonium and potassium thiosulfate are used commercially or experimentally as flower thinners because they are considered user, environment and consumer safe. The thinning trials were conducted in 2009 and 2010, on three- and four-year-old Braeburn Mariri Red* trees. The chemicals were applied at 1%, 2% and 3% rates of ammonium and 0.5%, 1% and 1.5% of potassium thiosulfate. Both thinning agents reduced fruit set, but were more efficient in 2009, when applied at 20% full bloom, than in 2010, when they were applied at 80% full bloom. Flower thinning with ammonium and potassium thiosulfate increased the average fruit weight, but the highest chemical rates retarded fruit growth. Ammonium and potassium thiosulfate did not affect fruit shape and firmness, but they increased starch degradation, total soluble solids content and titratable acidity. The treatments increased the percentage of flower buds, except at the highest chemical rates, where leaf damage reduced flower bud formation. Ammonium or potassium thiosulfate application may be recommended as the first step in a chemical thinning program

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.

Effect of timing of hand thinning on productivity of Moorpark apricots destined for drying

1999 ◽  
Vol 39 (7) ◽  
pp. 885 ◽  
Author(s):  
M. A. Rettke ◽  
A. P. Dahlenburg
Keyword(s):  
Fruit Development ◽  
South Australia ◽  
Fruit Weight ◽  
Fresh Fruit ◽  
Soluble Solids ◽  
Full Bloom ◽  
Total Soluble Solids ◽  
Fruit Thinning ◽  
Dried Fruit ◽  
Fruit Stone

Summary. Thinning at full bloom was compared with thinning at 3 stages of fruit development and the effects on size, total soluble solids level (TSS) and yield of apricots are reported. In 2 seasons separate branches of 9-year-old Moorpark apricot trees were hand-thinned to a density of 1 blossom or fruit per 50 mm of fruiting wood. Times of thinning were at full bloom, 5–15 mm size fruit, stone tip hardening and 21 days post stone tip hardening. These treatments were compared with an unthinned control. Experimentation was carried out at Loxton, South Australia. All thinning treatments reduced the yield of fresh fruit. Thinning reduced yield of dried fruit irrespective of timing in the first season but only at the 5–15 mm diameter fruit timing in the second season. Total soluble solids level of the fruit was increased by thinning which tended to improve drying ratio. Compared to the unthinned control all thinning treatments increased the size of fresh fruit. Mean fruit weight and diameter progressively decreased as thinning was delayed from full bloom till stone tip hardening. Thinning at full bloom produced higher yields of 35-mm-grade dried fruit than other treatments. To achieve the greatest benefit from thinning it should be carried out at blossoming.

scholarly journals Response of Mulching with Supplementary Irrigation on Physiochemical Properties of Bael (Aegle marmelos Correa.)

2020 ◽  
pp. 288-296
Author(s):  
Subham Ghosh ◽  
Shuvadeep Halder ◽  
Subrata Mahato
Keyword(s):  
Vitamin C ◽  
Sugar Content ◽  
Chemical Properties ◽  
Fruit Weight ◽  
Research Station ◽  
Anthocyanin Content ◽  
Aegle Marmelos ◽  
Total Sugar Content ◽  
Supplementary Irrigation ◽  
Basin Irrigation

The experiment was conducted at Horticultural Research Station, Mondouri, BCKV during 2015-2017 to find out the effect of mulching and supplementary irrigation on physical and chemical properties i.e fruit weight, length, diameter, pulp percentage, TSS, acidity, vitamin-C, anthocyanin etc. of Bael (Aegle marmelos Correa.) The experiment was put on factorial RBD consist of nine treatments viz.  M0I0 -  No mulch + no irrigation (Control). M0I1 - No mulch + basin irrigation with 15 litres/plant at 10 days interval, M0I2 - No mulch + basin irrigation with 15 litres/plant at 20 days interval, M1I0 - Black polythene mulching + no irrigation M1I1 - Black polythene mulching + basin irrigation with 15 litres/plant at 10 days interval, M1I2 - Black polythene mulching + basin irrigation with 15 litres/plant at 20 days interval. M2I0 - Dry leaves mulching + no irrigation, M2I1 - Dry leaves mulching + basin irrigation with 15 litres/plant at 10 days interval, M2I2 - Dry leaves mulching + basin irrigation with 15 litres/plant at 20 days interval. Which are interaction of two factor i.e. mulching and irrigation and each treatment has three replications. Mulching with black polythene followed by basin irrigation with 15 litres/plant at 10 days interval was most effective in improving fruit weight (1089.17g), size (length 12.89cm and diameter 39.18cm) and pulp content (56.16%) followed by dry leaves mulching + basin irrigation 15 litres/plant at 10 days interval. The fruit quality like vitamin C and anthocyanin content were also improved by mulching with black polythene followed by basin irrigation 15 litres/plant at 10 days interval but TSS, acidity whereas total sugar content in the fruits were not affected due to mulching and supplementary irrigation

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