Saturday, May 25, 2013

If you walk out into the orchard now (when it's not raining) you'll hear a buzz. The early apples - Zestar! and Ginger Gold - are in full bloom, the other apples are in various stages of bloom, and the bees that recently arrived from their winter home in California are busy flying through the orchard. It's a bit windier than they like it, and thunderstorms have been rolling in and out for the past several days, but the bees are still busy. 


Because last year the blossoms froze and the trees didn't produce many apples, this year the trees are putting out a super bloom.  Thousands of blossoms are popping out; the trees attempt to compensate for last year's disappointment.  So this year Farmer Bill will have to thin the apples.  Thinning can be done chemically or by hand, and he'll do both.  Zestar! are notorious for not setting well, so chemical thinning, a tricky process at best, can take out too many blossoms.  Farmer Bill will take a crew out to the orchard after the Zestar! apples have set and thin those rows by hand.  To get optimum size and flavor, apples should hang by themselves, at least a fist's distance from the next nearest apple.  Too many apples too close together means the apples stay small and can't get the sunlight they need to create their red color.


As soon as the apples start to form, we'll start scouting for Plum Curculio.  This pest of apples is one of the earliest; the adults mate about now and the females dig under the skin of developing apples to lay their eggs.  Most of the apples with PC eggs will drop early, but those that survive to maturity will have scars and won't be salable as first quality.

We've already started scouting for other pests.  About April 1 we put a data logger in the orchard.  It records the temperature every 15 minutes, and has an attachment that records leaf wetness.  The temperatures help us track degree days.  A combination of the leaf wetness hours and the temperature helps us track when apple scab spores will be most active and viable.  Apple scab is the major fungal problem facing apple growers.  In wet, humid areas like Minnesota it's especially problematic.  By tracking the temperature & wetness Farmer Bill can estimate when it's time to spray a fungicide to best attack the greatest number of spores.  He's done so well with this the last several years that he only has to spray twice, early in the year before the apples have even formed, to have virtually no apple scab in his orchard.  [I say only twice because conventional growers with scab problems will spray 5 or more times a year.  Organic growers have to spray every 10 days - or after a significant rain event - all summer long.  Good IPM management has its perks - fewer chemicals used to best advantage.]

The other pests we scout for in the orchard now are Codling Moth, Oblique-Banded Leaf Rollers, Red-Banded Leaf Rollers, Lesser Apple Worm, Spotted Tentiform Leaf Miners, and Dogwood Borers.  All of them are problems to one degree or another in most Minnesota orchards.  In July we'll add Apple Maggots, yet another nasty pest of apples.

The scouting takes time and materials.  We hang traps with liners covered in sticky stuff & put pheromone lures inside them; except for Plum Curculio, for which there isn't an effective lure.  Once a week, more often at times, I go out into the orchard & check all the traps, pull the data logger to retrieve the newest data, and create a report.  We're currently working with the MN Department of Agriculture, who take our data and data from several other orchards across the state to put together a weekly report.  The report is sent to orchards on an email list, and available online for anyone to see.  Those who don't have the resources or inclination to do their own scouting can use the report to help them time their pest control.  

And since Straight River Farm is also using Mating Disruption to fight codling moth, we put out a few extra traps to be sure we don't have a codling moth problem.  Mating Disruption works like this: we hang codling moth pheromone twist ties throughout the orchard.  There is so much scent of female codling moth all over the orchard that the males can't find an actual female.  Thus, no mating is done, the females don't dig into our apples to lay their eggs, the eggs don't hatch, and there are no larvae to worm their way through the apples (pun intended).  And this is done for something less than the cost of chemical spraying that would otherwise be necessary.  Pretty cool.  It's been very successful the previous 2 years in our orchard, so we're hoping it will be again this year.  But, just in case, we have multiple traps around the orchard and check them regularly.

It's a long haul from blossom to apple for an orchardist.  But aren't we lucky that there are farmers like Bill who make the long haul?

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