When A New Technology Saved The French Wine Industry

Amy Harmon's excellent, recent article in the New York Times describes how the Florida orange juice industry may soon be wiped-out because of a new bacterial disease spread by an introduced insect.  It looks like there could be a technology-fix for the problem using genetic engineering.  The question is whether the growers will get to apply that solution.

Coffee Rust - later these infected leaves fall off

The sort of crisis situation now facing the Florida orange industry is not at all unique in the history of farming.  There have been many times when some new pest  threatened the economic viability of a major crop.  Sometimes the pest "wins" and a particular farming industry simply goes away.  In the mid 1880s when Coffee Rust made it from Africa to the coffee plantations that supplied England from Java and Sri Lanka, the industry collapsed, and so the English had to switch to tea to get their caffeine.  When Wheat Stem Rust made it too hard to grow wheat in the Southern colonies of what would later become the US, the farmers shifted their cropping to cotton and tobacco.  That involved much higher labor requirements which in turn lead to the sad institution of slavery in that region.

But there have been other times when some new technological breakthrough has saved a threatened crop, as it possibly could for the Florida orange growers.  I'll give just one example here.

Back in 1874, a plant scientist name Pierre Millardet was walking down a road in Bordeaux France.  The famous vineyards he was passing were being devastated by a fungal disease called downy mildew.  It had been unwittingly brought across the Atlantic by the British who came back with specimens of the wild grape species they found in North America (e.g. Vitis labrusca - Concord types).  Those grapes harbored the downy mildew which was not too problematic for them, but the Vitis vinifera grapes of the Old World were extremely susceptible.  The wet climate of Europe was also ideal for fostering the fungal epidemic.

Grape downy mildew symptoms. Later leaves fall off.  Fruit can be effected too

Millardet was very concerned about this problem as were all the French looking at the possibility of not continuing to be able to produce wine.  As he walked past vineyard after vineyard nearly defoliated by the disease, he came upon one small part of a vineyard that looked remarkably healthy.  He quickly sought out the owner to ask why those vines looked so good.  It turned out that the grape grower had been frustrated by the fact that so many passer-bys on the road would help themselves to his grapes as they ripened.  He had concocted a mixture of copper sulfate and hydrated lime and sprayed it on the grapes to make them less attractive.

What the Bordeaux mix looks like sprayed on tomato leaves

By accident the farmer had developed a reasonably effective fungicide.  Millardet promoted that option, and soon the "Bordeaux mix" saved the French and other European grape industries.  It also saved the European potato crop which was also being devastated by a related disease that belatedly followed the potato from its origins in the Andes and caused the epic Irish Potato Famine.

Fortunately today we have many superior fungicide options to protect these crops.  Copper-based fungicides were "state of the art" in the 1870s, but by modern standards they are rather toxic to mammals, persistent in the environment, and bad for aquatic invertebrates.  One of their remaining uses is for organic farming which has only a few fungicide options that qualify as "natural."  New, synthetic fungicides that protect grapes, potatoes, wheat and other crops in Europe and elsewhere are far better for health and the environment. Still, without the accidental discovery of the "Bordeaux Mix," the European wine grape industry could have disappeared.

I gave an invited talk for the Specialty Coffee Association and its annual symposium back in February. The Arabica coffee growers in the highlands of Central and South America are facing a severe, new threat from a disease called coffee rust.  My role at the the conference was to put that crop threat into a global and historical perspective.  This grape disease story is one of the examples in my talk titled: "Humans vs Pests, The Long View."

You are welcome to comment here and/or to email me at savage.sd@gmail.com.  I tweet about new posts @grapedoc

Orange grove image from USDA-ARS
Coffee Rust (Hemileia vastatrix) image from Smartse
Grape Downy Mildew (Plasmopara viticola) image from the University of Georgia Photo Archive
Bordeaux mixture residue image from the Tomato Lover blog

In Which My Grand Daughter And I Became Flower Rescuers

My favorite fellow flower rescuer in action

One of the fun aspects of grandparenthood is getting up to speed with what is on children's television.  My personal favorite is "Shaun The Sheep," but one of my grand daughters Kay's favorites is "Go Diego Go."  Diego is a little kid that has adventures as an "animal rescuer."  The show tends to give the impression that wild animals can't really do very well without help, but at least it does expose kids to some biology.  Because of watching Diego, at 3 Kay can go to the zoo and accurately identify anything from a macaw to a pigmy marmoset.  But back to the flowers.  Here is the tale of how Kay and I became "flower rescuers".

For you Grandma!

About a quarter mile from our house there is a commercial greenhouse.  It is one of the few remaining floriculture operations from what was once a big industry here in northern San Diego County.  They produce beautiful gerbera daiseys for cut flower sales.  When they can't sell all they pick on a given day, they dump them for informal composting on an open area that Kay and I pass when we go for walks during her summer visits to Grandpa and Grandma's house.  She liked to scoop up bunches of flowers to take back to Grandma.  When I said she was a "flower rescuer" she loved the concept (These flowers recovered really well and lasted in a vase for several days).

Whole plants in the background during this rescue trip

On one of our visits to the flower graveyard we found hundreds of large gerbera daisy plants rooted in eight inch cubes of rock wool - a soilless growing medium that is used in the greenhouses.  It turns out that there was an infestation of "leaf miners" in the greenhouse and the grower was purging his supply to get rid of them.  Leaf miners are a nasty pest.   I certain kind of fly lays its eggs in the leaf and the larvae that hatch then burrow their way around inside of the leaf until they grow large enough to emerge as adults and repeat the cycle.  Many insecticides are useless against these pests because they are inside of the plant and not easily reached.

Leaf miner damage

Kay hated the idea of seeing the whole plants strewn in piles and dying, so I agreed to try to rescue some of them.  

Strollers can be good flower rescue vehicles

Saved gerberas after the dead and insect infested leaves were removed

We took the plants back to the house, cut off all the miner infested leaves, and planted these big plants in our flower beds.  It took a week or so to get the plants adjusted to being outside instead of in the greenhouse.  Some of the plants also had powdery mildew infections (a fungal disease) that I killed with some dilute dish soap (powdery mildews grow on the surface of leaves, so they can be killed with any surfactant if you have time to thoroughly apply it to both sides of every leaf).  Then with some fertilizer the plants began to thrive - producing their large flowers that are good for a week as a cut flower or even longer on the plant.

Happy transplanted gerberas on terraces in my backyard

Conscious of the fact that I am growing these plants close enough to the greenhouse for pests to move, I've also treated my plants with a nice product that is finally available to homeowners called "3-in-one Insect, Disease and Mite Control" that comes from Bayer.  It is for use on ornamental plants and it includes the systemic actives imidacloprid (something that would take care of any more leaf miners), tau-fluvinate (that would take care of mites), and tebuconazole (a fungicide which would prevent more powdery mildew in the future).  Don't worry about the imidacloprid hurting bees - I've watched and they don't visit the gerberas.  I'm now confident that I'm not putting the new flowers at the greenhouse at risk by planting them all over my yard.

I love having the chance to teach my grand daughter about plants, and I'm happy that she thinks being a "flower rescuer" is cool.  I'm enjoying that role as well.

You are welcome to comment here and/or to email me at savage.sd@gmail.com.  All images on this post are mine.  I tweet mostly about new posts @grapedoc.

By the way, if you are familiar with Go Diego Go or the related show Dora The Explorer, you should really see this faux trailer for a movie about Dora grown up