Pre & Post Bloom Orchards Sprays

BY KEN DAY

Most growers these days are applying nutrients with their early season fungicide sprays to orchard and vineyard crops. Is this really necessary? Which nutrients are beneficial? Is there any advantage to certain forms of nutrients? In this newsletter we’ll briefly touch on these questions.

The first simple reason to apply nutrients is that the application is free. The need of fungicides to protect bloom and early foliage has long since been established for trees and vines. Therefore, tank mixing nutrients with fungicides is an accepted practice based firstly on the fact that applying the nutrients has no further cost.

A second reason is that yield and quality responses to certain foliar applied nutrients have been well documented by universities for both orchards and vineyards. Bloom and early fruit set is the most critical period for setting and retaining fruit. Nutrients like Calcium and Boron are critical for pollen tube elongation and ultimately help assure the success of pollination. Nutrients like Iron, Manganese and Zinc are
critical for chlorophyll formation and leaf and fruit expansion. They help assure the early season photosynthetic potential of the crop. Flowering parts and emerging leaves are very tender and have less waxy cuticle than fully matured leaves. Therefore they absorb foliar applied nutrients more efficiently. All of the previously mentioned nutrients are not highly phloem mobile. Applying these nutrients directly on the flowers and early leaves requires that the nutrients move only short distances from where they enter the plant.

Which Nutrients?
The simple answer is, “It depends.”. It depends on which nutrients are in shortest supply. This is a question that can only be answered by experts who evaluate each field. There are, however, certain nutrients that have been shown to be deficient in most orchards and vineyards in the Western U.S. University and Extension studies have shown beneficial responses to foliar applications of these nutrients for orchards and vineyards.

Boron
Boron plays a critical part in the polymerization of cellulose and lignin fibers. It is critical for cell elongation and for the strength of cell walls.
Studies consistently show that foliar applications of Boron before bloom (pink bud in orchards) lead to improved fruit set and yield. According to studies by Dr. Patrick Brown of UC Davis, Boron applications during bloom are not recommended because they may increase Boron levels in the leaf tissues, but do not lead to better fruit set or yield.

In 2008 Dr. Brown conducted a study on the effects of FBSciences technology on the uptake and internal movement of Boron. His study showed that FBSciences technology added to foliar Boron sprays significantly increased the uptake and internal movement. 20% more boron was taken up through the leaves and translocated to the flowering parts and ultimately the seeds of the plants.

Calcium
For many tree crops, especially pome fruits and stone fruits, foliar applied Calcium sprays have been shown to improve fruit quality. This is logical,  since Calcium is a critical part of Calcium pectate, the “glue” that strengthens and cements cell walls. Calcium is not very mobile in the plant and studies show that applications of Calcium are most effective during the entire period of cell division and cell elongation. Multiple applications of Calcium, for example, have been required on apples to reduce bitter pit and improve storage life.

Studies by researchers in Michigan have shown that CellMate-F was more efficient than other foliar Calcium products at reducing bitter pit (a calcium deficiency symptom) on apples. A recent study by Holden Research showed that an amino acid chelated calcium foliar product performed significantly better for improving fruit quality when tank mixed with KAFÉ-F.

Zinc
Zinc is essential for proper cell elongation. It is deficient in many Western soils. Post bloom applications of Zinc help assure chlorophyll density and full expansion of the leaves. In vineyards, Zinc is also important for the full expansion of fruit bunches. University of California research has consistently shown favorable yield responses to post bloom applications of Zinc.

Zicron-F has been shown through research to have superior uptake and internal movement than less advanced formulations of Zinc. Studies by the University of California’s Dr. Patrick Brown showed that Zicron-F was the top rated commercial Zinc product in terms of foliar uptake efficiency

Iron and Manganese
Many Western orchards exhibit symptoms of Iron or Manganese chlorosis during spring and summer months. Normally the Iron and Manganese deficiencies are due to soil pH, free lime or high bicarbonate irrigation water. Carbonates and bicarbonates tie-up these nutrients in the soil, and make them less functional in the plants. Frequent foliar applications of Iron or Manganese may be required in order to assure normal chlorophyll formation and reduce symptoms of chlorosis.

In recent years, PhotoGreen-F has been used to turn around many chlorotic orchards and vineyards. KAFÉ-F has been shown through recent studies to enhance the performance of foliar applied manganese. Holden Research found that adding KAFÉ-F to a foliar Manganese product on citrus resulted in significantly better long term leaf tissue levels after the sprays. This study was conducted on citrus, which has a thick cuticle that tends to decrease foliar uptake efficiencies. KAFÉ-F treated trees had 46% higher manganese leaf tissue levels during the one month period after each of two sprays.

Copper
In many western soils, orchards have low Copper levels due to elevated soil pH levels. At such high soil pH levels Copper oxidizes into an insoluble precipitate that is unavailable for uptake. Under these conditions experts often recommend post bloom applications of low rates of Copper foliar products.

Recommendations
For highly efficient delivery of Calcium and Boron we recommend pre-bloom (pink bud) sprays of CellMate-F and Boron Boost-F. This program has been used by satisfied growers on thousands of acres of tree and nut crops in the US. Depending on the crop and soil, we recommend post bloom sprays with CellMate-F, PhotoGreen-F, Zicron-F, Manron-F, or Copron-F.

Recommended orchard spray program for a typical Western orchard:

• Pre-Bloom Sprays (”pink bud”)
  Boron Boost-F 1 pt/ac
  CellMate-F 1 qt/ac
  
• Post Petal Fall Sprays
  Zicron-F 3-4 pt/ac
  CellMate-F 2 qt/ac
  PhotoGreen-F 2 qt/ac
  Manron-F 1-2 qt/ac

A recommended vineyard spray program would be as follows:

• Pre-Bloom Spray
  Boron Boost-F 1 pt/ac
  
• Post Petal Fall Sprays
  Zicron-F 3-4 pt/ac
  PhotoGreen-F 2 qt/ac
  Manron-F 1-2 qt/ac

If you are pleased with the performance of other foliar products, but want to further enhance their uptake, movement and performance we suggest that you add KAFÉ-F to the tank mix at 6 to 12 oz per acre depending on the spray volume.