Monday, April 24, 2017

Why Are Roses in Vineyards?


Quiz time:
The reason wine grape growers place rose bushes at the end of their vineyard rows:
a) To alert them to a powdery mildew outbreak;
b) To alert them to an insect infestation;
c) Red roses mark the rows of red wine grapes; white, the white wine grape varieties.
d) They're pretty.

 d) is correct. Different strains of powdery mildew attack roses. Insects that bother both would attack the grapes first. And if the color of the rose indicated the varietal, then an apricot colored rose would mean that they are growing grapes for Boone's Farm Strawberry Hill wine.

Sacramento County Farm Advisor and Viticulture specialist Chuck Ingels says the practice may have been tried in Europe a long time ago to detect powdery mildew early, but it doesn't work. The mildew species that attacks grapes is a completely different species from that of the rose powdery mildew; and, they have different temperature requirements. Also, roses are more prone to get aphids; grapes, not so much.

For those at home keeping score:
Powdery mildew species on grapes: Erisiphe necator.
Powdery mildew species on roses: Sphaerotheca pannosa


Viticulture instructor Andy Walker at UC Davis says that roses are planted strictly for aesthetics.

 

This practice probably started in the early 20th century and continues to today; the myths and the stories about it came along the way.

One blogger took a trip to the vineyards of Italy recently where the winemaker discussed the issue: 
"Singore Razzi explained how they grow the grapes for their wine. We wondered why there were rose bushes at the end of each row of grapes and found out that very sophisticated tests were done by scientists on the soil and after those tests, the rose bushes were planted to tell the wine master how the soil is doing. If the roses stay fresh and perfect they know the grapes are doing just as well...when a bush is 'sick' they know those grapes growing in that row are 'sick' also.”


No winemaker is going to rely on roses to tell them about the quality of the wine. But it certainly impresses visitors; and, they probably bought more wine because of this sophisticated-sounding yarn.

So, how do wine grape growers control powdery mildew? With a rather large arsenal of chemical weapons. And for a good reason. Powdery mildew can develop a resistance if the same product is used over and over. According to the University of California Integrated Pest Management Program:

"Alternating fungicides with different modes of action is essential to prevent pathogen populations from developing resistance to classes of fungicides. This resistance management strategy should not include alternating or tank mixing with products to which resistance has already developed. Rotate with fungicides that have a different mode of action. Research has shown that sequential sprays of products with the same mode of action can lead to the development of reduced sensitivity to the active ingredient(s). Some fungicides have two active ingredients and thus two modes of action. When using such materials, do not alternate with other fungicides that contain one of the same modes of action (i.e. they represent the same fungicide class)."

Home gardeners and organic growers have a more limited selection to control powdery mildew.
According to UC IPM:

"Powdery mildew is a perennial problem in grapevines. Sulfur, horticultural oils, neem oil, jojoba oil, and Serenade are registered for controlling powdery mildew in home vineyards.
Begin applying treatments when all buds have pushed. Thereafter, repeat at 10-day intervals if disease pressure is high; otherwise, extend intervals when temperatures are above 90°F until the sugar content of the grapes is 12 to 15%, which is when they begin to soften and approach ripeness and are no longer susceptible to infection.
You can measure the sugar content with a refractometer, if you have access to one, or you can see if sample berries sink in a 15% sucrose solution. (Prepare the sucrose solution by dissolving 8-1/2 teaspoons of table sugar in a half cup of warm water, then mixing in enough cold water to make the total volume 1 cup.)"

More information about these products:


Fungicides. Several less-toxic fungicides are available for backyard trees and vines, including horticultural oils, neem oil, jojoba oil, sulfur, and the biological fungicide Serenade. With the exception of the oils, these materials are primarily preventive. Oils work best as eradicants but also work as good protectants. The fungicides listed here are registered for home use.

Oils. To eradicate powdery mildew infections, use a horticultural oil (such as Saf-T-Side Spray Oil, Sunspray Ultra-Fine Spray Oil) or one of the plant-based oils such as neem oil (such as Green Light Neem Concentrate) or jojoba oil (such as E-rase). Be careful, however, never to apply an oil spray within 2 weeks of a sulfur spray or plants may be injured. Some plants may be more sensitive than others, however, and the interval required between sulfur and oil sprays may be even longer; always consult the fungicide label for any special precautions. Also, oils should never be applied when temperatures are above 90°F or to drought-stressed plants. Horticultural oils as well as neem and jojoba oils are registered on a wide variety of crops. 

Sulfur. Sulfur products have been used to manage powdery mildew for centuries but are only effective when applied before disease symptoms appear. The best sulfur products to use for powdery mildew control in gardens are wettable sulfurs that are specially formulated with surfactants similar to those in dishwashing detergent (such as Safer Garden Fungicide). To avoid injury to the plant or tree, sulfurs should not be applied within 2 weeks of an oil spray, used on any plant when the temperature is near or over 90°F (80°F for caneberries and strawberry), and never applied at any temperature to apricot trees.

Biological Fungicides. Biological fungicides (such as Serenade) are commercially available beneficial microorganisms formulated into a product that, when sprayed on the plant, inhibit or destroy fungal pathogens. The active ingredient in Serenade is a bacterium, Bacillus subtilis, that helps prevent the powdery mildew from infecting the plant. While this product functions to kill the powdery mildew organism and is nontoxic to people, pets, and beneficial insects, it has not proven to be as effective as the oils or sulfur in controlling this disease.

Monday, April 17, 2017

Tips for Golden Age Gardening

   As we age, the spirit is willing, but the flesh is weaker...when it comes to gardening. The good news is: we have the experience and wisdom to garden smarter as we get older.

     Our enjoyment of growing fruit, flowers and vegetables seems to increase as the years fly by. Maybe it's because we've come to better appreciate how nature works. Maybe it's because we enjoy doing things closer to home. Or, maybe it's because plants don't talk back. 

     Whatever the reason, one thing is for certain: we don't bend down into a flower bed, lift bags of fertilizer and pull weeds as easily as we used to. As a result, we know that a few hours working briskly in the yard may result in an evening of moving slower.
   
    Still, there's no reason why you can't enjoy the good exercise of gardening (burning up to 7 calories a minute!). Just get rid of those tasks that are monotonous or excruciatingly difficult. Here are some tips for implementing an easy-care garden for the Golden Years, advice that can be summed up in four words: automate, elevate, eliminate, delegate.

Automate. Provide your garden with an automatic watering system. The efficiency of an automated sprinkler or drip irrigation system protects your plants from the summertime heat when you're away from home. And, a good drip system reduces water usage, unwanted weed growth and plant diseases. Replace your old irrigation control system with a model that can control more valves with more flexibility. For example, the Hunter line of irrigation control systems automatically adjust water run times based on the season and the weather. And it will automatically turn off your sprinklers if it senses rain. 

Consider installing battery operated water timers at distant faucets to control the watering of garden beds. The better ones not only turn the water on and off, but offer extended run times (perfect for drip irrigation) as well as multiple cycles per day (perfect for watering container plants on hot summer days).

Install low-voltage night lighting, equipped with sensors, to automatically come on at sunset throughout the yard.



Elevate. Build raised planters for your flowering plants and vegetables. Not only do raised beds reduce the amount of stooping and kneeling that are a necessary part of gardening, raised beds provide better drainage for plants that don't like "wet feet". Built of wood, concrete or brick, a raised bed, 18-24 inches high, gives you a place to sit while weeding, pruning or harvesting. Make the raised beds any length you desire; but keep the width less than four feet across for ease of reaching into the middle of the bed. And lining the bottom of these beds with quarter-inch mesh hardware cloth will keep gophers from sampling the fruits of your labor.

Eliminate. Life is too short to put up with a problem plant. Why waste time fretting over a habitually under-performing perennial, shrub or tree? Why tolerate tree litter or plant roots that are upheaving concrete? If it is growing awkwardly or is consistently pest infested despite your best efforts, get rid of it. Purchase another plant that will do better.


Although the attempt to totally eradicate weeds is an exercise in futility, adding three or four inches of mulch, such as a walk-on bark, can dramatically reduce the amount of time you spend pulling weeds.

If you really want to cut down on a monotonous garden chore, save money and time...get rid of the lawn! Mowing, edging, weeding a lawn can average an hour a week. Replace that ongoing chore with a garden area that is beautiful, uses much less water (with the right plants), and eliminates most weeding (thanks to several inches of mulch).

The area you see above was 1200 square feet of a bermudagrass lawn in nearly full sun. It was an area that was a lot of work to maintain and keep irrigated, and offered none of the benefits of a real garden. 


We replaced that lawn with what you see here: a fountain (that attracts birds and beneficial insects), dwarf fruit trees (such as the Garden Gold peach) and blueberries in containers, as well as native plants such as California buckwheat that attracts beneficials and pollinators. The best part? That area now uses 88% less water than the former lawn. And although it may sound heretical coming from me, there's nothing wrong with ripping out an underperforming turf area and replacing it with...an artificial turf putting green (top picture).

• Delegate. Somewhere in your neighborhood, there is the teenager looking to pick up some spending money doing yard chores (I know, that's like searching for the Holy Grail!); but there may also be the guy or gal who has that tractor, front loader, chipper-shredder, backhoe or whatever that could accomplish in a fraction of the time what you are attempting to do with a shovel, small mower or saw. Ask your neighbors for recommendations for professional landscapers and arborists. Check your home owner's insurance for coverage...and then seek them out. Parceling out yard work to others is tough for gardeners; but grit your teeth, open your wallet...and save your back.