Entrust – Lee Reich

Meet me in St. L . . . Seattle

Come hear me lecture on August 10, 2014 on “Luscious Landscaping, with Fruiting Trees, Shrubs, and Vines” at 1 pm in the Garden Room at Magnuson Park. For more information, go to http://www.brownpapertickets.com/event/755459.

Plague again; keep calm

Every year it seems some new plague is ready to attack plants. A few years ago, late blight of tomato moved to the fore. Emerald ash borer, threatening ash trees, was first found on our shores in 2002. (Figuratively; literally, the insect, native to Asia, was first noted in Michigan.) What’s next?

Perhaps a calmer outlook is called for. A decade or so garlic mustard seemed ready to take over our world. Not so, now, perhaps because it’s being crowded out by Japanese stilt grass, which itself seems now ready to take over our world. Garlic mustard is native over much of the northern hemisphere, except North America, and was introduced here around 1860 as a culinary herb. As for stilt grass, it hitchhiked here from China about a century ago, as packing material for porcelain. It’s deer-resistant, for what that’s worth.

Plant problems come and go. The best approach is to keep calm and, in some cases, plant something different, something plague resistant.

Bean Beetle Management

Green beans are a mainstay of my garden, of just about every garden. More than 20 years ago, Mexican bean beetles (a species of ladybug!) found my bean plants and have plagued them every year since.

The adults, with eight black spots over a red or yellow background, wake up late from winter sleep to lay eggs on bean leaves. I’ve come to despise the yellow, balled up spiny larvae that gorge on leaves and other plant parts.

Still, I have managed to grow good crops of beans over the years, not by killing the beetles or their larvae, but by growing a different plant. Sort of. Rather than grow pole beans, which reside in the garden all season long to provide a constant source of beetle food, I have been planting successive crops of bush beans. Bush bean plants tend to bear quickly and for about 3 weeks, then peter out, so a new planting in a new bed goes into the ground every 3 weeks from mid-May until late July.

Yield from a planting tapers off just as its resident beetle population is beginning a feeding frenzy. Then it’s time to pull up the plants, thoroughly clear the bed of leaves and old pods, and rush it all to the compost pile. Chopping the debris with a machete and burying it beneath straw and manure, and watering the pile, as needed, sends the temperature soaring, killing most of the beetles. Bean beetles are good fliers, so cooking the beetles in the compost pile doesn’t solve the problem, just keeps it under control.

Death to the beetles, with restraint

Something strange happened this year: As of this writing, only one beetle larvae has been seen. Last year I doused the bean plants a few times with one of two organic sprays, which gave good beetle control. It also gave me the confidence to try growing pole beans, as I did in my pre-Mexican bean beetle days. They got some bean beetles but we did harvest pole beans.

The sprays were Entrust and Azamax, both approved for organic agriculture. The active ingredient in Entrust is spinosad, a compound found in bacteria, Saccharopolyspora spinosa, that was isolated from soil collected inside an old rum still in the Virgin Islands. Although toxic to a range of insects, it is otherwise relatively benign. Still, the label requires waiting at least 3 days to harvest after spraying.

Azamax is an extract of the seed of the tropical neem tree, native to the Indian subcontinent. In that part of the world, this one tree has been used as human food, insect repellant, bird repellant, and an ingredient of soap. It degrades rapidly in soil or in water, and is harmless to earthworms, honeybees, and insect predators. Food crops can be harvested right after spraying Azamax.

Still, Azamax and Entrust are pesticides. Perhaps the bean beetle cycle has been broken here and sprays can be forgone in the future. I’ll keep calm. No sprays this year, yet.

SWD, go away

The same two organic sprays might be called upon for another pest, the spotted wing drosophila, unaffectionately known as SWD. Also an Asian import, this one has moved east since being first spotted in 2008 in California. It is hard to keep calm with this pest because it attacks blueberries, my favorite and heretofore my most reliable and abundant fruit crop. The pest is also fond of blackberries, raspberries, and — not that it matters to you or me, because we don’t eat them — honeysuckle berries.

Again, there are management options. Because SWD seems to blow in from more southerly locations, a fine net could exclude them. Prompt refrigeration of harvested berries for 3 days kills larvae within. Thorough harvest of sound and unsound berries also keeps populations in check.

And then there’s Entrust and Azamax (or some other neem product), any of which I consider a last resort. I’m setting up traps to monitor if and when SWD arrives. (For information on monitoring, see http://www.fruit.cornell.edu/spottedwing/monitoring.html.) Till then, and after, I’ll try to remain calm. Om. Om. Ah-oh-om.

Book Giveaway: AND THE WINNER IS: Andrea Jilling. Andrea, please contact me about mailing out the book. Everyone, stay tuned for more book giveaways in future weeks.

————————————-

Blueberry-growing used to be so boring. Each autumn I’d spread soybean meal beneath the plants as fertilizer and top it with 3 inches of leaves, wood shavings, or other mulch. Late each winter I’d prune. In late June, netting would go over the top of the plants and from then on, into September, I’d harvest oodles of blueberries.

Earlier this year I knew things could get interesting. Spotted wing drosophila (SWD), a new pest fond of many fruits, showed up last year in the area and an encore was predicted. And then, starting in early August, my harvested blueberries began to soften quickly and were soon swimming in their own juice. The culprit, SWD, was here, in numbers, with plenty of enticing berries still weighing down the branches.

“Drosophila” might sound familiar from experiments in your high school biology class; it’s a fruit fly. SWD differs from other fruit flies in not waiting for fruit to be ripe or overrripe. This impatient bugger lays eggs in unripe fruit.

Blueberry harvest is an almost daily affair and my blueberries are organic, sustainable, green, artisanal, (very) local, etc., etc., so I couldn’t just start spraying any old pesticide. Fortunately, there is one pesticide, called Entrust (derived from a bacterium collected from the soil of an abandoned sugar mill in the Virgin Isles), that is “organic” and effective against SWD. I did spray and now, despite the mildness of this material, we have to wait 3 days for the spray to dissipate before harvesting berries. Restraint is needed with Entrust because one generation to the next for SWD can take less than 2 weeks, leaving ample opportunity for resistant strains to evolve, especially if the pest overwinters locally (which is not known at this time).

After two sprays of Entrust one week apart, I should and will try something else, in this case a 1% oil spray — also “organic” and relatively benign. In laboratory settings, at least, oil has been effective.

What about all the berries on the plant with SWD eggs in them that are and will hatch into adults? Harvesting them and whisking them into a refrigerator at 34° for 72 hours will kill eggs and larvae. Same goes, of course for freezing them. Another option is to immerse them in that 1% oil mix for 5 to 10 minutes.

The battle against SWD should not — does not — end there. Fine netting encasing the plants could keep flies at bay, as long as it’s put on before SWD arrives or, if resident ones exist, after an early spray of Entrust. Thorough cleanup of infested fruits will keep populations down. We’re throwing soft fruits into a bag which goes into the freezer, and then it’s a dish of fresh frozen eggs and larvae and blueberries for my chickens. Mmmmm.

You might detect some flippancy in my attitude towards this serious pest. That’s because we already have 69 quarts of sound blueberries in the freezer.

(Thanks to Peter Jentsch and Cornell’s Hudson Valley information for much of this information.)

UPDATE: Two sprays of Entrust and one spray of horticultural oil, each spray a week apart, seem to have brought SWD under control. Once the berry harvest is over, we’ll let our free-range chickens access into the “Blueberry Temple” too clean up fallen fruit and resident SWD larvae.

—————————————-

Garlic has been harvested and, as usual, my yields and bulb sizes are nothing to brag about. “You should have cut off the scapes,” suggested more than one person, the scapes referring to the curly, bulbil-topped stalks that emerge from the centers of hardneck garlic plants.

I’m skeptical about scape removal. After all, that greenery does photosynthesize and, hence, help nourish the plant. And while seed development can drain a plant of energy, a scape is capped by small bulbils, not seeds.

A little research yielded widespread recommendations for scape removal, but hard data backing up that

recommendation was generally lacking. What I did learn was: 1) benefits of scape removal depend on the soil and variety of garlic; 2) benefits are greatest in poor soils; 3) benefits may be in terms of yield or bulb size. The most consistent reason to remove the scapes is that they are edible if harvested when just developing.

I don’t like the taste of the scapes so won’t bother removing them. I’m also not a big fan of garlic flavor so tend to plant them outside the garden in out-of-the-way locations where they’re never watered and the soil is not particularly rich. Hence, my poor showing of garlic.

—————————————-

The garlic is now curing as it hangs from the rafters of my front porch where it, fortunately, keeps its aroma to itself. Along the path leading up to the porch are a few plants whose aromas are a lot more welcome on the way to the front door. Those plants have clustered there not by some grand plan of mine, but just by chance.

Let’s see, first on the way to the door is Jasmine ‘Maid of Orleans’ (Jasminum sambac) whose flowers emit a pure, sweet aroma. The plant has been blooming more or less all summer but you do need to put your nose right up to the flower to smell it. Next comes jimson weed (Datura spp.) and angel’s trumpets

(Brugmansia spp.), both vespertine plants with 6-inch long, trumpet-shaped blossoms that appear sporadically. I’m always enjoying rose geranium, mint, and rosemary, next in line, because its their leaves that are aromatic; a pinch can send me to olfactory heaven anytime I wish, day or night.

Nestled in among these last-named plants is one small pot of alyssum. Alyssum blooms nonstop through summer and into autumn so the honeyed scent can be enjoyed whenever I pass, as long as I stick my nose down into the flowers.

Posts

Plagues Come & Go, With Some Help, and Seattle-time