Supplementing the Cuticle Provides Sunburn Protection and Fewer Dropped Fruit

Sunburn damage in citrus can negatively affect growth, productivity, and reduce fruit quality, which significantly decreases the growers’ marketable yields. Parka, applied in a program, provides sunburn protection and stress tolerance by increasing the plant’s antioxidant capacity and increasing key components that allow the plant to use the excess light energy for photosynthesis, preventing photo-oxidation that causes sunburn damage. Moreover, yields can be improved by applying Parka due to its ability to increase overall tree performance and reduce ethylene production responsible for fruit abscission.

Citrus Sunburn

Why use Parka on Citrus?

  • Proven to reduce sunburn damage by up to 48% over control.
  • Increases fruit grade and yield.
  • Increases plant tolerance to environmental extremes.
  • Allows subsequent application of insecticides and fungicides – a key benefit over traditional sunburn protection products.
  • Easily tank mixed with foliar nutrients and pesticides.
  • Leaves no visible residue.
  • Exempt from maximum residue levels.
  • Zero preharvest interval, zero worker reentry interval.

How to Use Parka in a Program

For Sunburn Protection

For sunburn protection, Parka applications should start after the initial fruit drop and be repeated every 30 days for a total of 3 applications.

And, because Parka is exempt from MRLs, has an excellent worker safety profile and does not have visible residue, it can be applied near harvest if necessary.


What Causes Sunburn in Citrus? 

Sunburn is caused by high temperatures and direct solar radiation that affects both leaves and fruits. Fruits are more susceptible to this type of damage than the leaves, primarily because they are less effective in using and/or dissipating excess solar radiation. Fruit sunburn symptoms can range from light bleaching to dark necrotic spots accompanied by cell death.

How Does Parka Prevent Sunburn Damage and Reduce Fruit Drop?

In the photosynthetically active tissue, the chlorophyll present in the PSII complex (1st step in photosynthesis) captures energy from the sun that is used to excite an electron that comes from the splitting of a water molecule. This excited electron is received by a molecule called pheophytin and is then used in the remaining photosynthetic process. Both chlorophyll and pheophytin are necessary tools plant cells need to deal with energy from the sun. Parka-treated trees are shown to contain higher concentrations of both components in leaves and fruits, which means the cells have a better capability to use the excess light energy for photosynthesis instead of allowing it to cause photo-oxidative damage.

Parka application also results in better overall tree performance and less fruit drop by increasing net CO2 exchange and transpiration rate. It also decreases ethylene production during the season. The reduction in ethylene is key in decreasing fruit drop, since this PGR is responsible for the production of enzymes that trigger fruit abscission.

Results Clementines
Citrus Fruit Drop
Citrus Sunburn

What Do Growers Like About Parka? 

Parka has reduced sunburn by up to 48% in trials resulting in increased marketable yields. It is grower and worker friendly. Parka is easily tank mixed with most foliar spray inputs and does not leave a white residue like reflective mineral based coatings. Harvest crews like Parka, because it does not leave the white residue of traditional sunburn products that can be an irritant during picking. An excellent worker safety profile, a zero pre- and post-harvest interval, and no maximum residue levels are also major advantages for growers.

In addition, crop protection products can be applied after a Parka application, a key benefit over mineral-based coatings.

Finally, packers like Parka, because the texture of the orange cuticle makes it difficult to scrub off the white residue. Because Parka does not need to be scrubbed off, it continues to protect the cuticle during storage. Parka is easily removed in modern packing facilities allowing for a clean surface to apply any post-harvest coatings.