RainGard is a hydrophobic protective film that maintains fruit integrity and quality by reducing fruit cracking. It is applied as a protective film on fruit, such as sweet cherries, to decrease rain water absorption through the cuticle. RainGard helps maintain cuticle strength all the way up to the final stages of fruit growth, thus reducing cracking susceptibility. Rain cracking is one of the main limitations in the production of high quality sweet cherries worldwide. RainGard can reduce cherry cracking by up to 50%.

Why do Sweet Cherries Crack?
A number of factors have been implicated as contributors to cherry rain cracking. These factors may include: rapid uptake of rain water absorbed through the fruit surface, rapid change in water status of the whole tree and high relative humidity.

The natural barrier to water uptake is the fruit’s cuticle. As cherries grow, the fruit skin becomes progressively thinner while the number and size of micro-cracks on the cuticle increase. The development of micro-cracks in the cuticle during rapid fruit expansion in stage III (“final swell”) has been reported as a crucial factor in cherry cracking susceptibility.

Multiple applications of RainGard have been shown to increase the integrity of the cherry cuticle and reduce susceptibility to cracking during rain events.

Source: Adapted from Peschel and Knoche (2005) J. Amer. Soc. Hort. Sci., 130:487-495
Fluorescence micrographs of sweet cherry fruit surface. (A) Intact fruit surface with stoma. (B-C) Small microcracks; typical of fruit in early stages of development. (D-F) More and larger microcracks; typical of fruit in the latest stages of development (Stage III).

Multiple Benefits of RainGard

Besides its notable property to suppress fruit cracking, RainGard can also provide the following additional benefits:

  • RainGard does not leave unsightly residue on fruit surface
  • RainGard has no affect on photosynthesis
  • RainGard does not negatively affect fruit quality parameters such as color, fruit firmness, or stem browning
  • RainGard can be mixed with most commonly used pesticides

How to Use

For best performance, use RainGard in a 3-application program.

Rate                             0.8%

Timing                          Make first application 4 weeks prior to estimated harvest date or when cherries
                                    reach straw color stage. Re-apply every 7-10 days until harvest.

Method                         Airblast

Spray Volume               100 to 200 gal/a (900 to 1800 L/ha)

Adjuvant                       Not recommended

Tank Mix                       May be applied with ProGibb Plant Growth Regulator

Refer to product label for directions

Maximizing RainGard Efficacy
• Apply a conditioning spray followed by a second application prior to rain
• Allow RainGard to dry for at least 2 hours prior to rain
• Spray fruit thoroughly to ensure adequate coverage
• Allow 24 hours before reapplication