Are too many blueberries to blame for sagging stems?

(Photo by Julie O’Connor)

For the last few years, my blueberries have had a problem – perhaps yours also. Rather than grow upright, the stems arch downward – some so drastically that they actually rest on the ground.

A few years ago, I pinned blame on the weather. Not that it was evident just how the weather could be responsible, but it’s always convenient, in gardening, to blame things on the weather. But this explanation is hardly convincing. Spring and summer weather have not been consistent enough over the years to be able to point my finger at too much rain and/or not enough sunlight (the combination of which could lead to those bowing branches).

How about pruning or fertilization? Too much of either could promote lush growth that couldn’t support itself. Except that my pruning has been consistent over many years. And Marvin Pritts, berry specialist at Cornell, confirmed that he and others saw the same problem, without definitive explanation, a couple of years ago.

I like the green-thumb explanation best: that is, that I’m such a good blueberry-grower that the branches can hardly support the prodigious crops that I’ve coaxed from them. So I’m not really complaining; just curious. And having to get on my knees to harvest low-hanging fruit.

There is one fly in the green-thumb ointment: a fly, literately. A tiny fruit fly called the spotted-wing drosophila, or – quicker to say, which is necessary for this fly that’s getting a lot of buzz lately – SWD. The fly attacks many small fruits, starting the season with honeysuckle berries, then moving on to raspberries, blackberries and…blueberries.

Most fruit flies lay their eggs in overripe or at least ripe fruit. Not SWD: She lays her eggs in unripe fruit. The eggs are small, and what hatch from them are small; their being “maggots” sort of takes the appeal from the berries.

SWD is a new pest, so new ways of thwarting them are being tried. Covering the plants with fine netting very early in the season is effective, but would be very bothersome – for my planting, at least. Various organic sprays are another possibility: Entrust, which is derived from a soil bacterium, is effective if used strictly according to directions; horticultural oil might prove effective. Traps are also under test.

One way to bypass the problem is to grow only earlier varieties of blueberries. SWD has not shown up here and at many other sites until early August. Plenty of varieties – Duke, Earliblue, Toro and Blueray, for example – are finished before then.

But I want fresh blueberries on into September. Harvesting blueberries (or raspberries or other berries) and whisking them into a refrigerator at 34 degrees for 72 hours will kill eggs and larvae. Freezing – the destiny of about half our harvest – also kills the eggs and any hatched larvae. A little egg and meat boosts the protein content of the berries.

It may be time for me to eat pie – not blueberry pie, but humble pie. Regular readers of my words probably realize that I take a certain amount of pleasure in iconoclasm. And one recipient of my eye-rolling has been compost tea: something that many gardeners and farmers love to love, even though there’s little theoretical or empirical support for its efficacy.

“Little” but not “none.” A number of peer-reviewed articles describe benefits from using non-aerated compost tea to thwart root diseases. (The relatively recent interest in compost tea is for aerated compost tea, often sprayed on leaves. Aerated compost tea, the brainchild and business of Dr. Elaine Ingham, is compost tea that’s bubbled with air for an extended period, often with molasses or other additions. Generally, experiments have not supported touted benefits of aerated compost tea.)

For the past number of years, my pea crops have been failures, the plants yellowing and dying soon after harvest begins. Fusarium or some other root disease is the probable cause.

In desperation, five times this spring, at about weekly intervals, I put a shovelful of compost into a five-gallon bucket and filled the bucket with water. After one day of steeping, the tea was strained, put into a watering can and drenched on the soil beneath my 30-foot double rows of peas. Lo and behold: The peas look healthy and have been yielding good crops!

I won’t say for sure that it was the compost tea, or what in the tea if it was the tea did the trick. But nothing else jumps out this year as the savior of my peas. For a more definitive tea endorsement, next year I should grow a row or two without the tea and a row or two with the tea. I might try that, although it presents the possibility of my ending up with a row or two of unproductive vines.

For now, I’ll just have humble pie (and tea).

 

Any gardening questions? E-mail Lee at [email protected] and he’ll try answering them directly or in his Almanac Weekly column. To read Lee’s previous “Gardener’s Notebook” columns, visit our website at HudsonValleyAlmanacWeekly.com.

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