Farm Progress is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Serving: East

Broccoli residue curbs vert on strawberries, trials show

Dried crop residue from broccoli can reduce verticillium wilt, a troublesome disease of strawberry production, according to a University of California, Davis plant pathologist.

Krishna V. Subbarao, stationed in Salinas, detailed his trials recently during a plant disease seminar there. His earlier research showed that a cauliflower crop following broccoli had less verticillium. That raised the question about whether broccoli planted before strawberries might have an effect.

Strawberries, extremely sensitive to the fungus, depend on fumigation with methyl bromide, which will be phased out of use by 2005.

His tests near Watsonville demonstrated that four crops of broccoli reduced verticillium in the soil. Broccoli has seven compounds that create an effect similar to that of the fumigant Vapam.

The broccoli residue was finely chopped and left to dry for 24 to 48 hours before being incorporated into the soil. It began to act against verticillium in about four weeks.

Subbarao, noting that strawberry transplants, in a commercial setting, can bring in verticillium wilt, said, "Broccoli can reduce the existing pathogen foundation, and it can also prevent infestation of the soil by Verticillium dahliae."

Mike Davis, also a UC, Davis plant pathologist, reported on his studies using garlic powder and an oil refining byproduct to control white rot of garlic and onion.

White rot, caused by Sclerotium cepivorum, is the most destructive disease of alliums and occurs worldwide. A field, once infested with the fungus, remains so indefinitely. No resistant varieties exist.

Tests have shown the disease present 40 years after a crop of garlic was grown on the land. Subsequent farming operations spread the disease across a field.

Central Valley growers avoid infested land and use only disease-free seed, but even so, Davis said, one or two new infested fields turn up in the valley each year.

Pathologists know the disease sclerotia germinate only in the presence of the disulfide compounds emitted by garlic or onions to produce the familiar odors. A single sclerotium per double handful of soil is sufficient to set off an infestation.

Treatments with the soil fumigated with methyl bromide and tarped kill only 98 to 99 percent of the disease, but the escapes are enough for an infestation.

Flooding of fields for a period of 10 to 12 weeks or longer is another method of destroying most of the disease, but it too is incomplete and it is costly, he said.

Referring to the disulfide compounds that set off germination of the disease, Davis said garlic or onion powder applied to the soil will deceive the white rot spores into germinating. In the absence of a host, they then starve.

"We can also use the liquid disulfide products from oil distillation. It has a strong smell of onions or garlic. We've done two experiments and have two more in progress," he said.

First garlic tests In the initial research in San Benito County with a small rototiller he incorporated rates of 50, 100, and 200 pounds per acre of garlic powder a few inches into the soil. Assays showed 95 to 96 percent of the disease spores were killed by the 100- and 200-pound rates after two years.

Davis said depth of the placement seems to have a bearing on the amount of the disease destroyed. Although a garlic crop started out well, as soon as its roots reached the spores they became infected. He hopes plots in progress using a moldboard plow, disk, and mulcher to a greater depth, perhaps to a foot, will do a better job.

Although the trials failed to eliminate white rot, Davis said they nevertheless are significant in helping to contain the spread of the disease.

Larry Bettiga, Monterey County farm advisor, reviewed efforts to control Pierce's Disease and its latest serious vector, the glassy-winged sharpshooter.

In addition to listing the symptoms and hosts of the disease and identification and riparian habitat of the vectors, Bettiga said the greater mobility and range of the GWSS to carry the disease represents a major threat to many perennial plants grown in California.

"We have focused a lot on the insect, but the main concern is the disease, and the long term solution will probably be in addressing the bacterium," he said. Results will depend on much research.

One possibility might be a non-pathological bacterium in a host plant's xylem that would have an antagonistic effect on the disease.

Another might be developing in vinifera grapes a resistance to the disease like that of muscadinia grapes of the southeastern United States.

Amazing asparagus can grow 10 inches in 24 hours under ideal conditions, produce for nearly 15 years and generate spears for six to seven weeks of spring and summer.

Gone are the days of the "honeymoon salad" - lettuce alone with no dressing. Today's vast assortment of greens and year-round availability of fresh produce ensure unlimited combinations of ingredients for deliciously interesting salads.

Asparagus is a member of the lily family.

Although Pierce's disease has been plaguing growers for more than a century, the culprit currently wreaking havoc over eight California counties is the Glassy-winged Sharpshooter. This half-inch-long insect with a voracious appetite is not a picky eater and is believed to dine on the stems of more than 70 species of plants.

If all the strawberries produced in California this year were laid berry to berry, they'd wrap around the world 15 times.

According to Egyptian hieroglyphics, the pharaohs loved mushrooms so much that they decreed them food for royalty; commoners were not allowed to eat them. Mushrooms continued to be a royal treat until Louis XIV began to grow them in caves near Paris. Because they are easy to grow and require little labor, mushrooms became a popular crop in France and England. In the late 19th century, people in the United States began to grow them. Today, mushroom cultivation is a profitable segment of California agriculture with a yield per acre of 2.44 million pounds.

You know strawberries are a big deal in California, but did you know just how big? There are more than 26,000 acres producing an average of 10 million pint baskets of the delectable little berries.

What wine goes well with strawberries? Champagne, of course. Be careful when opening that bottle though...Farm Bureau sources report that cork can exit a bottle at speeds up to 62 mph.

California cauliflower is a powerhouse of nutrition. One half-cup serving has 100 percent of the daily requirement of vitamin C plus calcium, potassium, fiber and It's good raw and crunchy or fabulous steamed and served with a sauce made from one of California's great cheeses.

More than 5,000 farmers participate every year in California's 341 certified farmers' markets.

Biotechnology can help farmers feed more people by making plants more nutritious, resistant to pests and diseases, and by extending their shelf life.

Nights are cooler, days are shorter and bears are getting ready to hibernate. Fall is the time to enjoy those good-for-you California comfort foods like potatoes. One of nature's most versatile foods, potatoes provide an abundance of vitamins, minerals and fiber. And they're available in colors: red, white, blue, yellow and purple.

A recent study found that the yellow jelly around tomato seeds keeps platelets in the blood from clumping together and forming killer clots that can block blood vessels. Research continues in the hope this may be an alternative therapy to aspirin, which can cause stomach upsets.

We love salad! Americans eat about 30 pounds of lettuce every year, about five times more than in the early 1900s.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.