Brian Murphy: A Peach of a Researcher

Brian Murphy, winner of the 2010 Francis R. Gouin Scholarship Grant, is helping solve the problem of storing peaches. With advisor Dr. Chris Walsh, he is conducting research on improving the quality of peaches in storage.

Store-bought peaches are frequently unedible. The most delicious peaches are grown locally and sold immediately upon harvesting. It’s impossible to harvest fully ripe peaches without bruising them, so they’re harvested after the skin appears yellow but while the fruit is still firm. Buyers must then to finish ripening the peaches at home at room temperature.

Most peaches sold in local grocery stores have been harvested when they are just starting to turn yellow. For shipping purposes, they are often stored at near freezing temperatures to delay ripening. However, such temperatures cause the peaches to become mealy and their flesh to turn brown.

If a peach is harvested green, it will never ripen, even at room temperature. The ripening process in peaches must begin on the tree, which is visible to the trained eye by the yellowing of the skin. Red color on peaches does not indicated ripeness; it only indicates that the peach has been exposed to direct sunlight.

Brian and his advisor are using a compound called 1-MCP to figure out what causes the internal breakdown of the flesh of peaches. During the harvesting season, they have been harvesting peaches, treating them with 1-MCP and storing them at 32, 41 and 50 degrees for zero, seven, 14, 21 and 28 days. The results will be compared to untreated comparable fruit stored under the same conditions.

Results are due soon.


Keep Your Azaleas Evergreen

The bottom leaves of my Delaware white azaleas are turning yellow and dropping to the ground. This is a clean indication that the nitrogen concentration in the soil surrounding the roots of my azalea plants is deficient. If you expect azalea leaves to fall, you’re missing information your plants are offering.

Only deciduous azaleas such as PJM, Exbury, Korean, etc. should be dropping their leaves. Most of the other commonly grown azaleas are evergreen varieties and should retain their foliage for at least one full year. When evergreen azaleas are hungry for nitrogen, you will notice that the very bottom leaves begin to turn yellow starting at the base of the leaf. This means that there is insufficient nitrogen in the soil, so the plant is stealing nitrogen from the older bottom leaves and translocating it to the developing flower bud. Unless additional nitrogen is added to the soil, the plant will continue to sacrifice the lower leaves in favor of the developing flower buds.

This problem can be resolved by mulching the azaleas with a one-inch thick layer of compost as soon as the symptoms first appear. Alternately, apply an azalea or ammonium sulfate fertilizer. Because azaleas can absorb only ammonium, never apply a lawn fertilizer or any other fertilizers containing high levels of nitrate nitrogen. Read the contents of the fertilizer bag before applying it.

Ask Dr. Gouin your questions at [email protected] All questions will appear in Bay Weekly. Please include your name and address.