YIELD / on Grapefruit

Study Investigator: John Curtis, PhD

Location of Study: Florida, USA, open field

Study Period: Mar. - Nov. 2014 and replicated in 2016

App 1

ONE Quart/Acre


App 2

ONE Quart/Acre


App 3

ONE Quart/Acre


App 4

ONE Pint/Acre


App 5

ONE Pint/Acre


App 1

TWO Quarts/acre

Bloom 50%

App 2

TWO Quarts/acre



2 programs tested: Program A (4 applications at 1 quart/acre), Program B (2 applications @ 2 quarts/acre) 

  • Block of 25 acres located Indian river district, FL USA


  • 1 row is 47 trees
  • 5 rows per treatment
  • 235 trees per treatment for 1 replicate
  • Rows: a;b;c;d;e
  • Treatments :
    • T1) Program (Qt per acre and Pint/acre)
    • T2) Program (2 Qts per acre)


  • Replicated x5 times per treatment
  • The 5 rows per treatment are randomized each time
  • Example, T1, replicate # 1 and the 5 rows are as follow:
    • R1 = Row Grower Standard
    • R2 = Row T1
    • R3 = Row T2
    • R4 = Row T1
    • R5 = Row T2
  • Each replicate then present a different order of the row via a scientific randomization.

 Total tree monitored:

  • 1,175 trees per treatment replicated 5 times
  • 2,350 trees total (2 treatments replicated 5 times) 
Juice & Brix data
  • All fruit data for juice content and pound solids was gathered by an independent packing house within Indian River District. 

  • Cyan 365® has been sprayed by conventional sprayer : rear pak- blast sprayer, 250 GPA


This study is even more outstanding because of the exceptional use of a mobile packing unit. This equipment gives a high reliability of this agronomic study. Packing houses is usually where the results can be easily corrupted. (traceability wise)

Early Fruit Drop (EFD)

One of the vicious effects of HLB is a noticeable increase in mature quality fruit drop. On infected trees, there is a serious decrease in the number of flowers that will set fruit and mature into marketable quality fruit.

Mid-June Fruit Drop (natural drop due to fruit competition)increases.

With HLB disease, early fruit drop is about 25-30% (Source: USDA, 2013).

The trees infected with HLB are experiencing more and more fruit drop.

Fruit quality is affected.

Contaminated trees have smaller fruit and internal quality is suffering.

Profit wise, it is extremely detrimental for the growers and the industry in general  ...

Bitter Taste with HLB

Another side effect from HLB: the bitter taste of the juice.

The fruit show an significant decrease in sugar content. (brix, fructose - pound solids). This is a big issue for both fresh and juice producers within the citrus industry.

Study Results




Pieces of fruit




Pieces of Fruit/Tree


Quality Yield


Early Fruit Drop


Pieces of fruit/Tree


More viable bearing fruit/Tree


Return Per Acre as (Market price index of 2014)

Agronomic study conducted from March to November 2014 and repeated with the same protocol in 2016. All operations were supervised and controlled by scientist John Curtis with his independent technical crew. The property used was a highly-reputed citrus grower’s commercial grove within the Indian River District (Florida).

THE PROGRAM [A] showed better results than program [B].

Here under results for program [A]:

Quality yield:

  • +96 boxes (+25%) extra yield of fruit per acre (TPA 120) Vs grower std.
  • +0.8 box per tree (+25%) extra yield of fruit per acre Vs grower std.
  • +66 fruit count per tree in average Vs the grower std.
  • +8,000 pieces of fruit per acre Vs the grower std.
  • -23% early fruit drop Vs the grover std.
  • -16 Early fruit drop count per tree in average.
  • +114% viable bearing fruit count.

Quality fruit:

  • +15% & +11% juice content respectively for the 40's and 32's sizes. (most significant for these 2 marketable sizes)
  • We have noticed significant improvements of Brix/Lbs solids for the sizes of 56's and 40's, respectively, +13% and +25%.
  • The Brix/Lbs solids data remains to be studied more extensively.

Fruit size distribution:

The AVERAGE fruit size breakdown per TREE provides significant improvement on the packout for the most valuable sizes:

  • + 75 pieces per tree, distributed as per graph. 

Return On Investment (ROI):

  • +$800 per acre

Notes: It is noticeable that for fresh fruits market, fruit size distribution results should be added to this $800 per acre.


Objectives: Ray Ruby red grapefruit on sour orange rootstock, 6 YO trees, severely affected by HLB, canker resurgence, early fruit drop, leafminer, melanoses, greasy spots, rust mites, etc.

For a better view of the graphs and charts, reposition your mobile device into landscape mode.

Variety Used: Ruby red grape fruit on sour orange rootstock, 6 YO trees, severely touched by HLB, canker resurgences, premature fruit drop, leaf minor...


One box is 90Lbs of fruit.

Extra yield Vs. Grower standard with Cyan 365® Prog. A: is 96 boxes per acre.

With an increase of 0.8 boxes per tree, you will increase your total box count with 96 boxes per acre @ TPA 120. As you may see with more fragmented applications as per program [A] or T1 at lower dosage you will obtain the best results than the program [B] or T2.

FRUIT SET and PREMATURE FRUIT DROP (in %) with CYAN 365® (Prog A) Vs the Grower Std.
Early fruit drop
  • -16 pcs per tree for the prog. A with Cyan 365® and compared to the Grower Std.
  • -23% Early fruit drop for the prog. A with Cyan 365® and compared to the Grower Std.
Remaining viable fruit count on the tree
  • +114%  viable bearing fruits in average per tree treated with Cyan 365® prog. A. 
  • Technic employed of the quadron as detailed in study for early fruit drop and viable remaining fruit.
  • Fruit count made after the natural fruit competition which is occuring for Grapefruit around mid-June
  • Fruit count made in September.
  • • 1 Box is 90 Lbs pounds of Fruit
  • • Boxes sold to packing house
  • • ROI which doesn't include the gain in sizes and early maturity parameters.


Fruit size distribution with CYAN 365® for the 75 Pcs of extra fruit collected but tree. (in Avg)

For the extra yield obtained with Prog A with Cyan 365® (+75 pieces of fruit per tree), the distribution of the fruit size is as here under (photo). In the meantime it is very important to notice here the presence of a mobile packing house unit which gives a great reliability for this experiment. Equipment which allow to give a higher credibility and reliability to this scientific and agronomic study.

The fruit size distribution is showing here the abilty of Cyan 365® to improve the sizes of the fruits in the most marketable and valuable sizes.


Marketable quality

30's are total 42%

40's are total 58%

For fresh, fruit size results here above shall be taken into consideration to achieve an even better Return on Investment.

  • • According Florida Citrus Maturity Chart from the department of agriculture (2014-15)
  • • For Grapefruit, 4 1/4 diameter or less resquires a minimum of 52% juice content.
  • • Accordingly and at November 2014, marker was set for 30's at 230 cc and 210 cc for the 40's 
  • • Cyan 365® works the best on the largest sizes. (40's and 30's)
  • Juice content is: +18% on the 30's to +15% for 40's