Biopesticides, Biostimulants Show Results In Fruits And Vegetables

Biopesticides, Biostimulants Show Results In Fruits And Vegetables

When many people think biocontrols, they think organic. But by far most farming in California is done conventionally, and because of that, David Holden — one of the expert presenters at the Biocontrols 2015 Conference & Tradeshow —  mostly focuses on his real-world experiences in conventional farming when discussing his research into biopesticides and biostimulants.


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There’s a reason “research” comes first in the name of his business, Holden Research and Consulting. “I’d say 90% of my work is in research, but I have done and do plenty of work in the field,” he says. “Probably 15 years ago that would have been the other way around, with 90% of my work consulting growers.”

When he says conventional farming, he means getting right down to the basics. For example, when most people think about fertilizers they think of nitrogen, phosphorous, and potassium (NPK), and with good reason, as those are the major nutrients. But there are biostimulants that can help plants mine the soil more efficiently. That means growers can reduce the amount of, say, N they are applying. And growers who haven’t had their heads stuck in the ground for the past decade know the issue of nitrogen lDavid Holdenevels in groundwater is becoming huge in California.

That’s just the beginning, says Holden. Phosphorous contamination of Midwestern water already is a big deal, and growers who don’t think that’s coming to California don’t know how state regulators work. Growers are advised to become well-versed in biostimulants and other technologies that can help them maximize effectiveness of fertilizers, conventional or otherwise.

Biostimulants Work In Avocadoes, Celery
One well-known area of biostimulants is seaweed, especially Ascophyllum nodosum. Holden has worked with Acadian Plant Science on the use of seaweed extracts, which are designed to enhance agricultural and horticultural crop productivity, plant vigor, plant nutrition, and crop fertility.

In fact, Holden presented some of that research in France in 2012 at the first World Conference on the Use of Biostimulants in Agriculture, which he will share at Biocontrols 2015. Used in conjunction with conventional pesticides, the biostimulants reduced the effects of persea mite and avocado thrips, the primary pests of avocadoes in California. “There were pretty dramatic results over three years on avocadoes,” he says. “It increased both the trees’ growth and protection mechanisms.”

Other research work on biostimulants that Holden plans to share is from a three-year project for the California Celery Research Advisory Board. Through the use of biostimulants, nitrogen inputs have been reduced 20%-25% on celery grown in coastal California, yet growers are still getting the same yields.

Biopesticides Increase Yields In Citrus, Strawberries
Holden will also share research he has done on some commercial biopesticides, such as MeloCon WG Biological Nematicide from Certis, which has a pretty broad registration across multiple crops. MeloCon WG contains a naturally occurring fungus, Paecilomyces lilacinus, that is a highly effective parasite of all stages of development of common plant-infecting nematodes, especially the eggs and infectious juveniles.

“Most of my research on this product has been in citrus, and I researched it for four years prior to its commercial release,” he says. “We saw bigger increases in trees, and definitely increased production in terms of fruit size development. The nematodes had been sucking the strength out of the trees.”

Another product he will discuss is TerraClean 5.0 from Biosafe Systems. Holden used it on a big problem for California strawberry growers, Macrophomina phaseolina, or Charcoal Rot, that has become devastating since the loss of methyl bromide. TerraClean 5.0, which has organic registration, controls a wide variety of soil-borne pathogens through drip irrigation systems.

“I will show data collected over the last two years on that pest,” he says. “We reduced incidence of disease and increased yields by using the product throughout the growing season.”