There are a number of products that can protect watermelons and other melons from sunburn. The newest product, Screen Duo, has been used by melon growers in Australia for several years. A late high rate applications will provide sunburn protection. The same amount of material, applied at lower rates beginning at bloom, will improve flower set, melon sizing, and provide late season sunburn protection. Growers choice, but if started early, many of the yield losses experienced in the Southeast this season could have been reduced.
For more info, see cropstress.com or the Certis website.
Some of the benefits for using Crop Shield are the ease of application, it is not sticky, it is not a clay or seal the plant from breathing and continuing to grow. It is not a polimer. It protects both the plant and fruit from both heat and cold damage depending on the time of year. If you have a heatlhy plant it is much more likely to protect itself from heat stress so nutritional balance is a must.
I use Kaolin clay and it works well
Unfortunatley, there are products that claim to solve nearly every problem under the sun, no pun intended!
The basic problem occurs due to a lack of vine cover with regards to sunburn or scalding on melons cucumbers and yes bell pepper as well. Growers and consumers should be weary of any product that makes claims of preventing or minimizing sun scald by any means other than improving the growth of canopy, which has multiple roles in production. Other than receiving sunlight canopy also serves the purpose of shading the crop! The only products that we are aware of should be used early on in the growing season and work in the soil to improve plant vigor and growth. As is the case with most ailments Prevention is the best medicine. If you are experieincing symptoms such as whitewashing, sunburn, or scalding it is merely an indicator that other significant problems are occurring in the crop!
Maintaining a good canopy is important and can reduce sunscald, but it is incorrect to say that there are no products that can reduce the damage. There is a wealth of data in numerous crops demonstrating the reduction in solar injury using materials that reflect light, as well as some biochemical materials that reduce the impact of the stressors on the crop. Of course, heat light water, and cold stress can all negatively impact canopy, so protecting the foliage from these stressors is beneficial.Plus, maintaining photosynthesis at higher rates due to the stress amelioration results in higher yields as well as improved quality. This is the next step in agricultural productivity. Proof that these materials work comes from what happens after harvest. In many places, the melons are left out under the sun. There are significant reductions in melon losses even under these types of handling. I suggest doing side-by-sides to see the difference and measure the benefits. Then calculate the return on investment. We typically see 3-8x ROI. For more info, www.cropstress.com.
Please do not mistake my comments. After reviewing my post it is clear there was no comment regarding whether or not there are products that can reduce the damage. Contraire, we have experience with a particular product that has demonstrated at the University level, replicated studies, showing significant improvements regarding vine cover and reduced "whitewashing" in watermelon crops. My wish was to shed some light on the subject from another perspective and with other facts to consider that had not been discussed. Again, one of the most critical things in melon production is to produce a very good vine that protects and shades the fruit which is the best and natural defense of these symptoms...so if you have products that help, great!