April 2012

Every day I wake up it seems as if I’m another week behind. I received a call yesterday morning from a grower in Palisade alerting me to his first codling moth catch of the season. Last year that event happened on May 2ndnd. For the last three years I’ve used WSU’s codling moth model to set a biofix and schedule control measures. The starting number that WSU’s model uses for a biofix is 175 DD. Yesterday’s degree day total in Palisade was 180. We’re off and running! In the 12 years I have on my biofix spreadsheet this is the earliest, but only by a few days. 2004 was April 4th and 2007 was April 3rd .

Here’s when the event occurred on the last few years using 175 DD as a biofix:

2011 Apr 21 2010 Apr 20 2009 Apr 19 2008 Apr 27 2007 Apr 3

If you’re in Mesa county and plan on using mating disruption for codling moth it’s time to get the dispensers up. ASAP!

I’ve not had time to check all of my biophenometers but as of this morning Cedaredge is at 105 and Olathe is at 155.

“If it will be….It’s up to me” “The window of opportunity is narrow – The timing of cultural activities through the year is critical” I heard Tom Mathison of Stemilt Growers make those statements a number of years ago at a cherry conference. In fruit growing timing is everything. Are you ready for late April’s activities…… today?

If you have a block of apples that is suffering from Wooly Apple Aphid (WAA) early in the season is the time to go to work on it. WAA over-winters on the roots of apple. Prior to bloom it starts the trek up the trunk to its’ summer home in the top of the tree. I came across information that states that an application at ½” green gave better results than one applied at full pink. By putting a chemical barrier around the trunk you can prevent migration. This is a very cost effective, non-disruptive program. Contact me about materials and rates.

I don’t know of a subject that draws more debate or varied opinions than that of calcium sprays. “It’s a must in my program!” “That calcium you sold me didn’t do a thing!” So what do the experts say? I read back through my collection of literature on calcium.

It functions in plant cell elongation and division, structure and permeability of cell membranes, nitrogen metabolism, and carbohydrate translocation. Considered a secondary or micro-nutrient even though the concentration of calcium in the plant is as great as nitrogen or potassium. Since calcium is part of the cell wall and acts as the cement that binds the cell walls together it is one of the most significant factors of firmness and storage life of fruit.

Water, containing elements and organic compounds, moves through the xylem up the tree. Stomates, which are small openings on the undersides of leaves, allow gases to move in and out of the leaf. Water evaporates from the stomatal openings in the process of transpiration, causing sap to be pulled through the xylem and into the leaf. This transpiration pull is responsible for the movement of water, containing nutrients, into the leaf and fruit.

Calcium moves very slowly in the tree and it may take more than a year for calcium to move from the roots to the leaves. Leaves transpire far more water than do fruit (stomates vs lenticels). Anything that reduces transpiration, such as high humidity, very low light levels, or drought stress, slows the movement of calcium up the tree. Because most transpiration occurs in the leaves, calcium moves preferentially into shoots and leaves, rather than into the fruit.

The cell division period is critical for Ca levels in the fruit. Early in the season prior to rapid shoot extension the fruitlet can

accumulate Ca on an equal basis with other demands in the tree. Once the tree gets cranked up the Ca gets sucked right by the fruit. As fruit enlarges there’s no additional internal Ca supply! The concentration of Ca in the fruit declines for the remainder of the season.

There are several reasons that calcium deficiency symptoms show up in fruit:

Quite often excess nitrogen is the cause. In an attempt to boost yields the first solution always seems to be ….. more N! A big shot of N causes the plant to grow faster than calcium can be moved within the plant. Nitrogen is translocated through the plant approximately 20 times faster than calcium. The increase in growth magnifies the problem.

As a rule, the larger the fruit the less the Ca concentration.
Excessive soil applications of K or Mg compete with Ca uptake, reducing it.
Lack of adequate soil moisture, especially during the 1st half of the season when growing roots take up Ca.

So what’s the solution? Pay attention to your overall program. Don’t get too aggressive with vigor, don’t let the orchard suffer for water and keep your nutritional program within bounds. If you do decide to supplement with Ca, keep in mind the early window during bloom and immediately post bloom before rapid shoot extension starts. Later in the season, applications of Ca must contact the fruit to be effective. Give me a call to discuss the different formulations of calcium available.

Thanks for your business!

Larry

970-234-3424