PRESIDENT'S MESSAGE

By Don Dramstad

As the April-May monsoons continue into late May, planting season is in full swing. Between the rain showers diligent dahlia growers have been racing to their gardens to get the 2008 planting underway. John Spangenberg reports plantings nearing 700 and I am sure Nick Weber is not far behind.

A two-day effort was needed this year to get the Trial Garden at Derwood planted. On Saturday John, Tom Davis and I prepped the garden beds in preparation for Sunday's planting. We had touch and go weather for Sunday, but the rain held off long enough for the gang of Chris Costa, Tom and Yvonne Davis, John Spangenberg, Lou Wiest, Ray Myers, Nick Weber, Harry Rissetto to plant 35 entries from around the world along with another 80 named varieties. All we need now is help from all of the members to make the 2008 season a banner year for the trial garden and a memorable stop on the Alan Fisher post ADS Show tour.

The final plant sale of the year will be on June 11 at Bethesda Library. This is your last chance to get some great replacement and fill in plants to make your garden spectacular. Fertilizer, markers, etc. will also be available at great prices. See you there!

HERE A DAHLIA, THERE A DAHLIA

 
By Alan A. Fisher

Would you believe that I received 28 potroots from Europe on May 30? Two previous packages never made it through customs, but Geerlings was remarkably loyal and resent until the package reached me. At this late date, I probably cannot plant 28 potroots, especially if I’ll be able to divide some of them. Look for me at the June meeting if you might want to try some new dahlias from Geerlings.

Before I left for Alabama, I had only enough time to place about 30 dahlias into the ground. In short, I’ll be planting 85 percent of my dahlias in June -- by far the latest I have ever gotten started.

Dahlia Care in June
This year, most of the insects seem to be late. I have seen few dahlia pests so far other than slugs (all over) and chipmunks (Lord High Executioner Ko Ko has not been very effective at chipmunk control). At least chipmunks seem to ignore dahlias, and slug bait controls slugs. Normally we see aphids by some time during May. I have not seen any aphids, but I suspect that anyone who has not sprayed is likely to see them by now. Aphids spread dahlia mosaic virus, by far the most common virus in dahlias and a common virus in many dozen other weeds and plants. Anyone who permits aphids in the garden is asking for problems, because aphids can infect an entire dahlia garden very quickly. I have seen some dahlia gardens full of dahlia mosaic virus, and it is a sickening sight. Whether you use “organic” methods (such as M-Pede, a professional strength insecticidal soap and horticultural oil) or “organic chemistry” controls (such as Marathon and Talstar), guard against aphids.

Some plants that I received during May already had two-spotted red spider mites. I sprayed and saturated fronts and backs of the foliage with Hexygon (which kills mite eggs), Pylon (which kills other stages), and Phyton 27 (a copped product that kills mites). The new foliage has come in clean, but I need to watch carefully and spray again to be certain that I have controlled all the current and subsequent generations of mites on these plants. When the hot, humid, rain-free weather starts, mites grow explosively. “Organic” methods such as M-Pede, horticultural oil, and Phyton 27 are also effective on mites, as are some “organic chemistry” products such as Avid, Phylon, Hexygon, and Floramite. The keys to effective mite control include starting early to control mites before they become established and rotating the chemical classes regularly to reduce the risk of the mites becoming resistant to chemicals. If any plants show extensive mite damage, remove the plants completely and throw the entire plant into a plastic trash bag. It is virtually impossible to kill all the mites on a badly damaged plant, and the mites that remain will reproduce quickly to develop generations of mites resistant to any chemicals that failed to kill them. Mite control is necessary in our area from the beginning of June until the weather turns cold some time in October.

Glenn Ruth

Ron Miner passed along the sad news of the passing of Glenn Ruth earlier in May. Hannah and I are dismayed to lose Glenn, who was one of our best friends in ADS. When the kids were young and we traveled regularly to and from Hannah's family in Michigan, we always stopped en route to visit Glenn and Jan Ruth. Glenn would show me his cloth house and pass along numerous tips about growing the best dahlias. Glenn was also one of the best photographers in ADS. No matter how fine my photos, Glenn's were always better. (So were his dahlias.) Jan was a great cook and took great efforts to make delicious meals that fit in with our religious dietary restrictions. For a number of years, until he was in his mid 90s, Dick Howells would drive in and make it a better party.

Glenn Ruth was a mentor to every significant dahlia grower in Ohio for decades. He was a mentor to me, and I only saw him a few times a year. He was one of the most giving people I knew, and also one of the most gracious. He always thought that people did him a favor keeping in touch with him. He never realized that we got more out of the relationship than he could possibly appreciate. A person as fine as Glenn Ruth comes along only on rare occasions. He will live on in the memories of those who knew and loved him.

AROUND THE PATCH

By Harry Rissetto

March 24 . . . The time has come to visit the tubers and wake them from their winter’s hibernation. This is always an adventure, because I do not have the initiative to check on them during the turn of the year. This will be the final test in last years gardening adventure. The clumps grew in a manure mixture, and we had relatively little moisture during the last months of the season. I dipped the tubers in a Cleary’s solution before storage in vermiculite filled bags. Next week, we will have a grade for tuber rot, crown rot, fungus and just plain “dry-out.”
Over the years I have read about “curing” tubers before storage. When I have tried to “cure” the tubers after digging, they just became soft. Consequently, I have taken to putting them away as soon as possible after they are dug. I have also read about the virtues of not washing the clumps. That sounds appealing---if they do not grow in soil with a lot of clay. I am always amazed that in the UK many growers just store the clumps, upside down, in newspaper-lined boxes under the greenhouse staging. I have a friend with a root-cellar and he just puts the clumps on shelving, and they mostly do fine.
All of this leads me to conclude that some clumps store easily and others don’t. The latter will soon be gone from our gardens and show-tables. This form of natural selection is healthy for the dahlia because the biggest complaint from the average gardener is that dahlias are too hard to keep over the winter. We can tell them to “grow dahlias as an annual and leave them in the ground after frost.” But it would be better if we bred new cultivars for tuber resilience as well as color, form and stem. We ought to make a list of the dahlia cultivars that have nice blooms and are easy to cut up and store. Any candidates?
A number of our local members plant out tubers in late April. In most areas around Washington DC there is little danger of frost—although Alan’s Rockville patch may be an exception. Nevertheless, I tend to wait until Memorial Day weekend to give time for the soil to warm up. Cold, damp soil is a real test for both tuber and plant. One year I tried a few sprouted tubers with the “wall of water” gadget. The plants survived, but they didn’t seem noticeably more vigorous, and the wall of water was difficult to remove, when I got around to it in June. A couple of gallons of water in a plastic sleeve is tricky to handle.
I have better luck starting tubers in pots during late April and giving the root systems a month to develop before putting them in the patch. It is a matter of space and the potential for thrips and mites, if the greenhouse warms up. Mark Alger had some cold-frames out back, and that seemed to work as plant motels, once they developed root systems and could take the elements. More on the “hardening-off” process next month.
Good root systems and conscientious hardening-off are two keys to a strong start.
I have a plastic box outside the greenhouse, and it is filled with dirt-filled pots that held plants that died last year before I could get them in the ground. I have no idea what caused these disasters—mostly new introductions. But they are a reminder that after all these years, we are still learning, and the lessons are sometimes costly—but not as costly as a round of golf at Raspberry Falls.
Most importantly, growing dahlias is a hobby. Have fun!!!

MINUTE BY MINUTE

By Nick Weber

Our March meeting seemed long in coming since our February meeting had been canceled due to inclement weather. However, all was forgotten and forgiven once our speaker Steve Bogash from the Penn State Cooperative Extension began his unforgettable lecture on “Soft/
Biorational” Pesticide Options for Vegetable & Flower Growers: Insects, Disease and Weed Control”. If you missed this talk you really missed something. Steve dealt with all manner of pests from insects to fungi, to weeds and more.

Mr. Bogash not only shared what products do show efficacy, but also mentioned those that did not or were clearly not effective in his estimation. Soft pest management materials: have very low mammalian toxicity (high LD 50) for both oral and dermal exposures; have very low fish toxicity (nontoxic or low / minimum impact); have very low bee toxicity (nontoxic or low / minimum impact). These will typically carry either no signal word or be labeled “Caution.” Steve further pointed out that Biorational pesticides refers primarily to pesticides of natural origin that are 1) mined materials, 2)plant extracts, 3)bacteria, or 4)fungi and fungal extracts. He further described them as having limited to no adverse effects on the environment, minimal activity on non-target organisms, and or very selective. He also pointed out that - The term biorational is derived from the words biological and rational and the word Biorational does not have a legal EPA definition at this time.

As for products to consider for weed control, Steve mentioned Racer and Scythe which are burn down materials as well as corn gluten (poor efficacy) and high strength acetic acid (stronger than you can buy in the grocery). He did say that Roundup (glyphosate) really had few equals and mentioned a unique way to employ it as a “Wick Stick”, PVC, hockey stick device containing concentrated glyphosate with a nylon cord bottom wick. Steve reviewed the fungicides, Amicarb O, and Milstop (both potassium bicarbonate – this is not baking soda which is sodium bicarbonate). Sequential applications can damage leaf waxy cuticle. Oils including Neem Oil also have some antifungal activity. He mentioned that M-Pede has a label against powdery mildew, but was minimally effective in the field. Steve spoke more highly about the effects of phosphonic acid products like Phostrol, ProPhyte, and Topaz on downy mildew as preventatives, but not for control. He pointed out that Copper formulations like Phyton 27, Kocide, and Champ have been recognized for fungicide and bacteriocide efficacy for some time. Micronized Sulfur and Yellow Jacket are both sulfur containing products and are excellent for powdery mildew, but you must be watchful of phytotoxicity especially in warm weather applications. A new product, Tricon is both an insecticide and fungicide, but there is only one year of experience with this one. A fungus (Tricoderma hazardium T-22) has had positive results in preventing certain root rots and is widely being used for this purpose. It goes by the names of Root Shield or Plant Shield. Similarly, bacterial products like Subtilex, Companion and Rhapsody containing Bacillus subtillus are effective on mildews, rusts, leaf spots, and botrytis. Likewise another bacterium, Streptomyces lydicus (Actinovate AG), has broad effectiveness against soil fungi.

Insecticides were a third area where Steve listed several soft or biorational products. These included the oils and Neem Oil, again with the caution of possible plant toxicity. Spinosad containing products like SpinTor, Entrust and Conserve were mentioned for their broad activity against various caterpillar larvae and are safe for most beneficial insect populations except bees. Pyrethrum containing products like Pyola and Pyganic have effective knockdown properties for most insects, but some get up to fight another day. Steve mentioned Sabadilla Dust as effective against grasshoppers as well as being a broad spectrum insecticide. Interestingly, a fungal extract in BotaniGard ES controls a wide range of insects. Of course we all have heard of Bacillus thuringiensis, BT, that now has many strains as products like Dipel, Thuricide, Javelin, etc., that are effective on various moth, fly, mosquito, and beetle larvae. Look for a new strain next year called BuiBui that is expected to be in a formulation that is a step forward against Japanese beetle larvae. Gnatrol has been around for some time for fungus gnats as soil drench. Mr. Bogash strongly recommended that we use the safer molluscicides, Sluggo and Escar-go, because of their safety and high effectiveness against slugs.

It was clear from this provocative and interesting program that there are a lot of effective new products aimed at many of the insect and fungal pests we confront in our gardens.

What was truly inspirational about this talk was that it now appears that a high degree of control for pests exists using biorational approaches. In truth, this is an area that is rapidly developing and for which data comparisons with our usual chemicals are not yet available. The point is - good pest control has been observed with many of the newer biorational products. The bottom line is consider using some less toxic yet potent new comers and see how they compare to the standard “Big Gun” arsenals that many of us employ.