Spray Thinning, Growth Regulators & Sun Burn Protection


Tree Row Volume Spraying

Tree row volume spraying adjusts the amount of chemical required depending on the tree size or foliage volume.

The volume of concentrate sprays applied to standard trees will contribute to over-spraying of higher density trees if the spray volume is not adjusted to suit the smaller trees. This is particularly critical with blossom thinning sprays, where over thinning may occur. There may also be variable results with hormone thinning materials and other growth regulators. Avoiding over-spraying will reduce risk to beneficial insects and mites and will also increase predator survival, reduce chemical residues and costs.

See Tree Row Volume Spraying in Introduction section of Pesticides for information on calibrating amounts needed.  Your crop advisor or fieldman is able to assist you in tree row volume calculations for your orchard.

Spray Thinning of Apples

Even when pollination conditions and tree vigour are satisfactory, spray thinning apples always involves calculated risks. Inadequate fruit removal is a more common result than excessive thinning. However, some years natural fruit set may be poor and applying a fruit thinning spray may excessively reduce final fruit set and crop load.

Recommended products include naphthalene acetic acid (NAA) (Fruitone L, Fruitone N), the amide salt of NAA (Amid-Thin), 6BA (Cilis or MaxCel) and carbaryl (Sevin XLR) alone or in combination to reduce fruit set of apples.

All fruit management practices, and spray thinning in particular, may require adjustment to work well in your orchard. Keep careful records of your spray thinning results in order to make appropriate adjustments for each block and to ensure improved fruit quality. When possible, leave some trees untreated for comparison purposes. 

Blossom Thinning

Reducing initial fruit set by blossom thinning will increase the amount of return bloom the following spring as well as improve fruit size and crop load in the current season.  A foliar nutrient spray applied during bloom has proven effective in this regard. Descriptions of the specific effects of the nitrogen and sulphur containing fertilizer, ammonium thiosulphate (ATS) are found under Fruit Tree Nutrition. Note the precautions listed for the use of this chemical.

Post-Bloom Thinning

Apply Amid-Thin shortly after petal fall (between 5 and 10 days after full bloom), NAA products from 7 to 12 days after full bloom and Sevin XLR is effective between 10 and 25 days after full bloom and even later in some seasons. The effective timing for a NAA product and Sevin XLR mixture is between 15 and 20 days after full bloom. Cilis or MaxCel, used alone or in combination with Sevin XLR, should be applied when king fruitlets are 5 to 10 mm in diameter, a period that may extend 7 to 21 days after full bloom.

The extent of fruit development at the time of spraying is an important consideration and in seasons when post-bloom weather is consistently warm and bright these thinners should be applied early in their recommended period. If the weather is cool and fruit development is slow they should be applied later.

When used by itself, Sevin XLR results in good fruit thinning when the largest fruits are 10-15mm in diameter and the outlook is for several days of bright and warm weather. Temperatures should reach 20° C or higher within 5 days of application.

NAA products used alone should be applied when the largest fruit are 8 -10 mm in diameter and air temperatures are at least 10° C. Best uptake of NAA occurs under slow drying conditions (cloudy, humid).

When applying the mixture of an NAA product and Sevin XLR, apply when the conditions are most suitable for Sevin XLR.

Materials and Strength for Hormone Application

Naphthalene acetamide (Amid-Thin) may be applied to any variety except Red Delicious where applications may result in the retention of ‘pygmy’ apples. Applying Amid-Thin in less than 1700 L of water/ha (680L/acre) may not be effective since absorption of the chemical occurs only at the time of spraying. The chemical is inactivated by light so no significant additional absorption occurs if the leaves are rewetted. Slow-drying and / or low light conditions favour absorption. Thinning results may not be evident for as much as three weeks after spray application.

Naphthalene acetic acid (NAA) (Fruitone L, Fruittome N) used alone tends to be less effective than Sevin, but when mixed with Sevin XLR will strongly promote fruit thinning. NAA, however, applied somewhat earlier than Sevin XLR or the Sevin XLR plus NAA mixture, may prove adequate and is worthy of consideration, particularly where Sevin-induced mite build-ups have been experienced. NAA can be applied to all varieties but caution is required with Red Delicious. NAA products may over-thin non-spur Red Delicious and spur-type strains may exhibit “pygmy apples”. Use at least 2250 L/ha (900 L/acre) to achieve good wetting and thorough coverage and use a surfactant with a NAA product. See the following table for the suggested rates. This is a general suggestion and growers are encouraged to experiment with NAA products. Apply higher rates on hard-to-thin varieties and lower rates on easy-to-thin varieties.

Carbaryl (Sevin XLR ) is effective on all varieties, including Red Delicious. Sevin XLR is now registered for use as an apple fruit thinner and should be selected over older formulations since it is less hazardous to bees. However, Sevin XLR can harm predatory mites.  For that reason, Amid-Thin should be given first consideration for post-bloom thinning of all varieties except Red Delicious. Application of Sevin XLR to Red Delicious trees that have not reached full bearing can result in over thinning. The thinning effect of Sevin XLR and full extent of drop may not be evident for 3-4 weeks after application. Sevin XLR has a relatively low solubility in water. It is very important to apply Sevin XLR in at least 1700 L/ha (680L/acre).

NOTE: Sevin XLR can only be applied for thinning once per season. Re-entry interval 12 h - 17 days depending on orchard contact activity. PHI is 75 days for thinning rate application. Consult the label for mixing and application instructions for hard to thin varieties.

Sevin XLR and Fruitone L or N (NAA) mixtures effectively thin Spartan, McIntosh, Golden Delicious, and Spur Red Delicious apples when applied 15 – 20 days after full bloom. This combination may be questionable for non-spur Red Delicious as it removes more fruit than either chemical applied singly. The suggested rates for each material are listed in the following table. This spray should be applied with at least 2250 L/ha (900 L/acre) of water to achieve good wetting and thorough coverage. To increase or decrease the activity of NAA plus Sevin XLR mixture, increase or decrease the amount of NAA product in the mixture. Do not alter the rate of Sevin XLR.

Cilis or MaxCel and Sevin XLR mixtures for post-bloom thinning and Cilis or MaxCel for mild thinning and fruit size enhancement. Cilis or MaxCel will increase the fruitlet thinning activity of carbaryl on a wide range of apple cultivars. Cilis and MaxCel contain 1.9% 6-benzyladenine (also known as N-(phenyl-methyl)-1H-purine-6-amine, or 6BA), a natural plant hormone that functions as a mild fruit thinner when applied when the king fruits are between 5 and 10 mm in diameter. Unlike Accel, Cilis and MaxCel can be applied at rates higher than 100 ppm, as such significant thinning can be achieved with these products. The addition of carbaryl to Cilis or MaxCel will increase the amount of thinning activity at any rate, reducing the amount of Cilis or MaxCel necessary to achieve adequate thinning results. Cilis or MaxCel applications can begin at Petal Fall or 6 mm, follow up applications may be necessary to achieve the desired thinning results.

For fruit thinning and the promotion of return flowering, apply Cilis or MaxCel by airblast sprayer in combination with Sevin XLR. Applications made when the king fruits are about 10 mm in diameter have given good results. Use sufficient spray volume to achieve complete coverage. Slow drying conditions found in the early morning or late evenings will increase uptake of the active ingredients. Daytime temperatures in the 20° to 27° C range during the week following spraying will optimize the amount of thinning and fruit size achieved with the Cilis or MaxCel plus carbaryl combination.

Unlike Accel, Cilis and MaxCel can be used in spray thinning programs with Fruitone L or N; although, the use of Fruitone L or N on Fuji or Reds should still be avoided to prevent the retention of pygmy fruit.

The use of Cilis or MaxCel alone to achieve some fruitlet thinning and increase fruit size may require two applications. The timing is when the king fruit is about 5 mm in diameter and again 7-10 days later.

Spray Thinning of Some New Apple Cultivars

While local experience is still being gained, mature bearing trees of all new cultivars will, likely, require thinning to maintain annual production and achieve good fruit quality. The following comments and suggestions are for those growers thinning Gala, Fuji, Jonagold, Ambrosia and Aurora Golden Gala:

Gala apple blooms over a long period and young trees have a tendency to flower on one-year wood. Fruit size of Gala is small to medium. An aggressive thinning program will improve fruit size and ensure an adequate return bloom. Sevin XLR is the most suitable material but trials with Amid-Thin alone or followed by Sevin XLR could be considered. Use the rates listed in the table. Combinations of Sevin XLR and Cilis or MaxCel may also help improve size of Gala. Multiple spray thinning applications may be necessary to achieve adequate thinning.

Ambrosia will need a fairly aggressive thinning program to achieve the desired size ranges.  Most growers will apply one or more blossom nutrient sprays followed by post bloom thinners that may include Sevin XLR and Cilis or MaxCel. Some growers have found Ambrosia may be thinned very easily, grower experience in individual blocks will help to prevent crop reductions due to over thinning. Where over thinning has occurred in the past, growers are advised to try a nibble approach, using multiple applications of thinners to achieve the desired level of thinning.

Aurora Golden Gala is another variety that needs aggressive thinning to achieve good fruit size. Several blossom nutrient sprays followed by post bloom thinners such as Sevin XLR and/or Cilis or MaxCel sprays will be necessary. Reports from Ontario indicate that applications of Promalin may assist with thinning and improve the shape of the fruit from young trees.

Jonagold is a triploid cultivar that should be relatively easy to thin. Amid-Thin will likely be the preferred material and trials involving “dilute” sprays applied 5 - 10 days after petal fall are suggested. Sevin XLR is also suggested on a trial basis. Use the rates listed in the table.

Fuji is often very difficult to thin and growers will need to consider an aggressive thinning program. Bloom thinning sprays followed by several post bloom sprays that could include Sevin, Cilis or MaxCel and Fruitone L or N.

Braeburn and Granny Smith are easy to thin and many growers do not chemical thin these varieties. If thinning is needed, a lower rate of Sevin XLR could be used.

Spray Thinning Pollinizer Trees

Trees planted strictly for pollination may be thinned more severely and otherwise managed to insure reliable flowering. A suggested thinning treatment is Amid-Thin (25g/100L) plus Ethrel (125ml/100L) applied with a hand gun 5 - 10 days after bloom. Do not allow this spray to drift onto commercial varieties. Since crabapple pollinizers flower mainly on one year wood, pruning shortly after bloom also helps to maximize return bloom and can be used to control the size and shape of these trees.

SPRAY THINNING OF APPLES – HORMONE MATERIALS

Materials

Air-blast Sprayer

Dilute

Varieties

 

per hectare

per acre

per 1000 L

 

Amid-Thin   

plus a non-ionic surfactant.

1.40 kg

 

560 g

 

200 g

 

All except  Delicious

Sevin XLR

0.5 - 3.22 L

0.2 - 1.3 L

 

All varieties.  Apply 0.5 - 3.22 L/ha for to spindle to super spindle trees. Apply 0.5 - 2.15 L/ha to all other tree density plantings. Do not spray trees which have not reached full bearing. REI: 12 h - 17 days.

Sevin XLR

plus

Cilis or MaxCel

0.5 - 3.22 L

 

2.5 to 6.25 L

0.2 - 1.3 L

 

1 to 2.5 L

 

 

2.35 L to 5.88 L

All varieties.  See rates above. 

Sevin XLR*

plus 

NAA (3.1%) 

Fruitone N

Fruitone L

50-100 mL

 

 

410 g

410 mL

20-40 mL

 

 

164 g

164 mL

 

 

 

160 g

160 mL

All varieties. Apply higher rates for hard to thin varieties.

McIntosh, Spartan, Golden Delicious,

Spur Red Delicious (and hard to thin new varieties)

Spray Thinning of Bartlett Pears

Where Bartlett set is heavy, a dilute (spray gun application) of Amid-Thin often results in satisfactory fruit thinning. The optimal rate will vary from orchard to orchard. Apply Amid-Thin at 13 - 21 days after full bloom. Apply only to vigorous trees with a heavy set. Thinning results may not be evident until about three weeks after spraying.

 

SPRAY THINNING OF BARTLETT PEARS  – HORMONE MATERIALS

Material

Air-blast Sprayer

Dilute

 

per hectare

per acre

per 1000 L

Amid-Thin 

plus

non-ionic surfactant

500 g

200 g 200 g

Stop-Drop Sprays for Apples

Tree Row Volume Spraying

See the discussion at the beginning of this section.

Apples

McIntosh and Spartan apple trees are prone to excessive preharvest fruit drop. This problem can be reduced by applying ReTain (AVG) or naphthalene acetic acid (NAA).  Since NAA may result in over mature fruit at harvest time, growers are not encouraged to use this product. The BC Tree Fruits Cooperative will not accept fruit treated with NAA for stop drop. If you plan on using an NAA produc, consult your packinghouse field service prior to application.

ReTain- A Harvest Management Tool for Apples

ReTain contains 15% aminoethoxyvinylglycine (AVG), a biologically derived inhibitor of ethylene production in plants. In tree fruits it delays preharvest drop of all apple varieties prone to this problem, delaying water core development, slowing fruit ripening (e.g., softening, starch degradation) and reducing fruit cracking of Gala and other varieties. Treated apple trees can be harvested later than normal without risk of fruit drop or internal quality deterioration. There are also reports of improved fruit firmness and reduced incidence of storage scald after CA storage.

ReTain is applied four weeks before normal anticipated harvest (i.e., this timing may be as early as 3 weeks before actual harvest). Experience has shown that applications slightly later than 4 weeks before harvest do not significantly affect performance. Note that in some years the development of red colour is delayed after the application of Retain in treated Galas and Spartan blocks.

Each package of ReTain contains 333 grams of material, or 50 grams active ingredient. The label rate for all apple cultivars is 125 g active ingredient (2.5 packages) per hectare (50 g/acre = 1 package/A) applied with enough water to thoroughly wet the fruit and foliage (about 900 L/ha, 80 gallons imp/acre). To achieve good coverage and efficient use of the product, tree row volume principles (see page 11-13) should be used. A properly calibrated and maintained sprayer and the addition of an organosilicone wetting agent, Sylgard 309 at 0.05%-0.1% by volume (500 - 1000 ml/1000 L) are essential ingredients of the application protocol. When high temperature (in excess of 32 degrees C) weather conditions prevail or are anticipated, the 0.05% v/v rate is recommended. Absorption of ReTain is improved by slow drying conditions. Avoid weather conditions where spray drift onto non-target crops could occur. Do not spray if rain is forecast within the next 8 hours.

Since the benefits of ReTain relate to the inhibition of natural ethylene production, it should not be mixed with NAA or ethephon, which increase ethylene production in apple fruits.

Fruitone L, Fruitone N (NAA )

These products require uniform coverage and are most effective when applied in a high volume spray not less than 2250 L/ha or 900 L/acre. Uptake of NAA is best under warm, but slow drying conditions.

NAA takes effect about two days after application and will be effective in reducing fruit drop for a period of approximately 10 days.

Treatment with NAA promotes ripening of apples. Therefore, application earlier than one week before anticipated harvest, double spraying or late harvesting may result in soft apples at harvest.

To minimize the adverse effect of NAA and to avoid excessive fruit drop after the effective stop-drop period for NAA has been exceeded, apply NAA products no earlier than 10 days prior to anticipated harvest completion date.

CAUTION: Take great care to avoid spray drift on to trees of a variety other than the target variety. For example, when NAA is being applied to McIntosh, there must be no spray drift on Golden Delicious, Spartan, Red Delicious or other varieties, otherwise premature ripening and softening of fruit of those later varieties will occur.

 

STOP-DROP APPLICATION FOR APPLES *

 

Material

Quantity per

 

Time to Apply

Duration  Effectiveness from Time of Application

 

Medium Volume

High Volume*

 

 

 

1700 L/

hectare

680 L/

acre

Per

1000 L

 

 

Retain (AVG)

Plus

Sylgard 309

445 -832 g

 

0.05-0.1%

180-333 g

 

0.05-0.1%

 

4 weeks before the start of the anticipated harvest of the treated fruit

37 to 40 days after application (7-10 days after the beginning of normal harvest of untreated fruit)

OR in exceptional circumstances

 

 

 

 

 

NAA 3.1% powder (Fruitone N) or liquid (Fruitone L)

3 kg

3 L

1.2 kg

1.2 L

580 g

580 mL

2 days before expected drop, but not earlier than 10 days before anticipated harvest completion date.

10 days from

date of application

See Pesticide Application Equipment.

Other Growth Regulator Techniques

The Ethephon Early-Ripening Technique for Apples*

* Please note that this practice is discouraged by industry packinghouses at the present time

Use Ethephon (Ethrel) to advance colouring and ripening of McIntosh and Tydeman apples, thus permitting early harvesting of treated fruit. However, successful use of ethephon requires careful attention to details of timing, spraying, harvesting and delivery of fruit to the packing-house. Therefore, growers interested in using ethephon to advance harvest are strongly advised to contact their fieldman or crop advisor for advice on questions of suitability of their operation for adoption of this technique. They should also contact their packinghouse regarding questions of allocations, handling and receiving of ethephon-treated fruit.

Since an important advantage for the industry at large is the availability of high quality McIntosh early in their marketing season and since ethephon-treated fruit is not suitable for CA storage, there will be considerably less interest in receiving ethephon-treated McIntosh after the main McIntosh harvest is underway and the CA rooms are being filled.

How to use Ethephon

1.  Treat only red strains of McIntosh and other varieties maturing earlier than McIntosh. Striped strains may not colour well even when treated with ethephon.

2.  Spray only trees in good vigour and having good-sized fruit. Early ripening may reduce tonnage compared to untreated blocks in the same orchard.

3.  Fruit sprayed 2 - 4 weeks before their normal harvest date may develop desirable colour and good eating quality within 6 - 8 days of spraying, depending somewhat on prevailing temperatures. Warmer temperatures advance ripening but in some cases may retard colouring. Fruit pressure test readings recorded daily will accurately indicate the extent of fruit ripening and can be used to select the best harvest date. The precise spray date must be arrived at after consultation with your shipper since treated fruit must be harvested, delivered and in cold storage not later than 10 days following treatment. Adequate harvest help must be available. All bins of treated apples must be identified with labels (supplied by the shipper) attached to each bin. Since ripe apples soften rapidly, growers who do not follow the above instruction risk having their fruit down-graded because of over-maturity.

4.  Ethephon is best applied as a high volume or gun spray.

5.   Avoid use of ethephon (Ethrel) in mixed plantings.

 

ETHEPHON APPLICATION

Material

Preferred Application Method

(high volume or gun sprayers)

 

Tydemans

McIntosh

 

Amount

Per 1000 L

Amount

Per 1000 L

ethephon (Ethrel) 

60 to 90  mL

1.25 L

 

 

Alternate Application Method
Medium Volume – use at least 1100 L/ha (400 L/acre)

Material

Preferred Application Method

(high volume or gun sprayers)

 

Tydemans

McIntosh

 

Amount

Per Hectare

Amount

Per Acre

Amount

Per

Hectare

Amount

Per

Acre

ethephon (Ethrel) 

2 to 3 L

0.8 to

1.2 L

4.25 L

1.7 L

 

*  See table on Stop-drop Applications for Apples
for equivalent NAA materials.

Ethephon (Ethrel) to Promote Return Bloom

Ethephon can be used alone to promote flowering on vigorous non-bearing trees. Apply 300ppm ethephon (1.25 L Ethrel 24%/1000L) in a dilute spray at 3 to 5 weeks after bloom.

Perlan and Promalin

Red Delicious apples produced in some locations may lack the “typiness” demanded by certain markets.
Perlan and Promalin are mixtures of benzyladenine and two gibberellins; their application can improve fruit shape when applied as king blossoms are opening. 

To improve fruit shape, apply Perlan or Promalin at a rate of 1.25 - 2.3 L/ha (500 - 900 mL/acre) in a medium volume spray (2250 L/ha) (900 L/acre) or 125 mL/100 L (567 mL/100 gal imp). Addition of a registered surfactant should prove beneficial.

PRECAUTIONS

1.  Perlan and Promalin are known to thin apple blossoms. Weak or frost-injured flowers appear to be particularly susceptible. On such trees, Perlan or Promalin usage may also increase the amount of thinning achieved with a subsequent blossom thinning spray.

2.  Where spur vigour is low or where the king blossoms have been damaged by frost, the fruit lengthening response to Perlan or Promalin may be negligible.

3.  Do not apply Perlan or Promalin if rain is expected within 6 hours.

Gibberellic Acid Use on Sweet Cherries

The normal harvest period for sweet cherries can be delayed 5 to 7 days and several aspects of fruit quality can be improved by a single spray of gibberellic acid applied about 3 weeks before normal harvest (the straw-yellow stage of fruit maturity).

This treatment delays red colour development, increases fruit firmness and fruit size, and delays the period of maximum sensitivity to rain splitting. Gibberellic acid-treated fruit is less likely to develop the postharvest disorder known as “cherry pitting”.

There are now four registered products containing gibberellic acid - Activol,  Falgro, Florgib 4L, GroSpurt GS-4 and ProGibb 40 SG.

Activol

Activol contains 0.92 g of gibberellic acid per tablet. Dissolve 20 tablets in 1000 L water (20 ppm) and apply as a foliar spray 21 days before expected harvest. The fruit is usually in straw-coloured stage. Do not harvest with 21 days of harvest. Research in BC has shown ripening is delayed 4-5 days.

Falgro

Falgro contains 1g of gibberellic acid in each tablet. To prepare the recommended spray concentration of 20 ppm active ingredient, dissolve 20 Falgro tablets in 1000L of water (9 tablets per 100 gal imp). Add 250 ml of Agral 90 non-ionic surfactant per 1000L (113ml/100gal imp). Apply as a high volume spray (see page 11-15) to full foliage wetness.

GroSpurt GS-4

Make one application of 20-50 ppm (50-125 mL/100 L) when the fruit is light green to straw coloured in sufficient water to ensure thorough wetting (to point of run-off). PHI - 7 days.

ProGibb 40 SG

ProGibb contains 40 percent active ingredient or 1 gram of active ingredient (GA) for every 2.5 grams of product. To make a 20 ppm concentration spray mixture, add 50 grams of ProGibb for every 1000 litres of water (22.5 grams per 100 gal imp). Apply as a high volume spray (see page 11-15) to full foliage wetness.

When applying either Falgro, Fruitsize or ProGibb apply at least 2250 L/ha (900 L/acre) of the spray mixture. Harvest the fruit at the desired shade of red skin colour. Falgro and FruitSize have a pre-harvest interval of 21 days; ProGibb has a pre-harvest interval of 28 days.

Gibberellic Use on other Tree Fruits

GroSpurt GS-4

Peach - Apply 200 ppm (500 mL/100 L) twice per season (full bloom and fruit set) in sufficient water to ensure thorough wetting (to point of run-off). 

Prune plum - Apply 40-125 ppm (100-312 mL/100 L) only once 4-5 weeks before expected harvest in sufficient water to ensure thorough wetting (to pint of run off). 

Other stone fruit - Apply 40-80 ppm (100-200 mL/100 L) only once 3 weeks before expected harvest in sufficient water to ensure thorough wetting (to point of run-off).

Apple and Pear - Apply 10-50 ppm (25-125 mL/100 L) once only at early fruit set in sufficient water to ensure thorough wetting (to point of run off). 

Apogee

Apogee (27.5% prohexadione calcium) is registered growth control product for apples.  Apogee acts within apple trees to inhibit the biosynthesis of gibberellin, which results in reduced vegetative growth.  Suppression of growth may last from 2 – 5 weeks following application and does not affect growth in the following year.  Apogee may cause the tree to retain more fruit, so more aggressive thinning programs may be required.

Application

Apply Apogee with enough water to thoroughly cover the tree foliage.  Apply the first spray at 5 cm growth stage, followed by a second application 14 -21 days later.  Refer to the following table for application rates. Consult the label for more detailed information:

APOGEE APPLICATION - APPLES

Application Timing

Apogee rate per 100L of dilute spray

Apogee rate per hectare

Medium to high vigour (split applications) (fire blight suppression)

45 grams

1350 grams

Low to medium vigour (split applications)

27 grams

810 grams

Low vigour trees (single application)

27-45 grams

810 – 1350 grams

Fire blight Suppression

To reduce fire blight secondary infections (shoot blight), apply Apogee at 2.5cm to 7.5 cm of shoot growth and apply at intervals of 14 – 21 days up to a maximum of 4 applications per season.  Rates are the same as medium to high vigour growth in the table above. Apogee does not prevent blossom infection.

Prevention of Sunburn and Heat Stress in Apples and Pears

Raynox

Raynox is a foliar product specifically designed to control sunburn. Raynox must be applied on its own and applications of pesticides, nutrients or ReTain should be made just prior to application or reapplication of Raynox, as the fresh coating of Raynox may interfere with absorption. Raynox dries in about one hour, avoid drift onto vehicles and housing, and wash machinery immediately after applying Raynox. Do not apply Raynox if the temperature will exceed 29°C during application. Apply at a rate of 23 L per hectare in 1000 L of water. or 9.5L /acre in 450L of water. The first application should be applied prior to a sun burning event or at the golf ball fruit size (42 mm) and reapplied every 2 to 4 weeks.

Surround WP Crop Protectant 

When Surround WP is applied to plants, a white particle-film is formed which is infrared- and UV-light reflective. Plant surfaces treated with Surround WP are cooler under summer heat-load. As a result, Surround WP may reduce sunburn and heat stress on fruit and foliage.

Application:

Begin applications of Surround WP soon after crop thinning and before the onset of hot conditions.  Make initial applications at the high rate, 4 bags per 1000 L water per hectare (50 kg in 1000 L water, a 5% solution).  To ensure thorough and even coverage, make follow-up applications at the lower rate, 2 bags per 1000 L (25 kg in 1000 L water, a 2.5% solution).  Surround WP dries to a white haze on plant surfaces.  Make low-rate applications to maintain the visible film.

Purshade and Purshade-O

Purshade is a new calcium carbonate (Lime) based spray product. Purshade leaves a protective film after application that reflects Ultra-Violet and Infra-Red radiation, lowering both plant and fruit surface temperatures, which in turn reduces sun induced disorders, such as sunburn. Begin applications once the fruit reach 19 mm, with follow up applications every 2 to 3 weeks. The first application should be made at the high rate, 30 L per hectare (12 L per acre); follow up applications can be made at the lower rate, 20 L per hectare (8 L per acre). Purshade should be applied as a low volume spray, as high spray volumes may cause pooling of the product and reduce efficacy.

For Suppression of Splitting in Cherry Blocks

VaporGard

Applications of VaporGard form a protective barrier on the surface of the fruit that prevents or reduces the absorption of water into the fruit. Begin applications of VaporGard at pit hardening, 3 - 4 weeks prior to harvest, apply 9.4 L per hectare (3.75 L per acre), and make repeat applications on a 7 - 10 day schedule, as the activity of VaporGard is best within a few days of application. VaporGard must be applied during daylight hours and needs at least one hour of drying time prior to a rainstorm to be effective. VaporGard can be applied right up till harvest, as VaporGard has a zero day pre-harvest interval.

RainGard

RainGard is a fruit protection product developed at Washington State University. The activity of RainGard is best within a few days of application, as full fruit coverage is necessary for adequate fruit protection, and coverage diminishes as the fruit grows. Begin applications at pit hardening, apply 23 L per hectare (9.5 L per acre), making follow up applications on a 7 day schedule. Raingard should be applied in 475 L per hectare (42 gal imp per acre), if applications of RainGard are made in higher water volumes per area, raise the application rate to maintain a 5% solution or 5 L per 100 L (23 L per 100 gal imp). Do not apply Raingard to fruit with visible residues (ie from certain nutrients, Wettable Powders, etc). Applications of  other spray products should be made either prior to the application of RainGard or at least 4 days after the application of RainGard.

Parka

Apply 8 - 16 L of Parka in 800 - 1600 L of water per hectare (1% solution). Do not exceed 1600 L/ha per application. For best results, apply Parka in a two- application program with the first application at late straw color. Reapply in 7 – 10 days after the first application. Timing between first and second application may be lengthened depending on occurrence of rain events. Do not apply when the air temperature exceeds 29°C.

For more detailed application instructions and precautions, refer to the product labels.

Fruit Colour Management

Exposure of fruit to sunlight with good pruning practices will always give the best colour development. Other horticultural practices such as over-head irrigation and balanced nutrition can sometimes be helpful in apple colour development (see Fruit Tree Nutrition). Discuss the use of over-head irrigation with an irrigation specialist or horticulturist before applying this practice. Also consult a horticulturist if considering installing reflective ground fabric to aid in colour development.

BLUSH

BLUSH (5.25% prohydrojasmon) is a plant growth regulator for use on red apples to promote fruit colour development. Make 1-2 applications of 100-200 ppm at 7-14 day intervals, 7-28 days prior to anticipated harvest. It works best if climatic conditions allow an extended drying period. Apply in the morning or evening when temperatures are lower and humidity tends to be higher than during the day. Read the product label for more instructions on preparing concentrations (ppm) and application.