Accompanying the current spate of Macrophomina and Fusarium discoveries by the UCCE Diagnostic Laboratory in Salinas and by other pathologists, growers, farm managers, and PCAs are now faced with the question of what the next step should be.

Fumigation: The advice for growers and farm managers is to avoid bed fumigation at this juncture.  Even beds fumigated by professional operators will have little reservoirs of surviving pathogens on the shoulders where the fumigant did not travel.  Of great concern are pathogen populations surviving in the soil making up the untreated furrows.  Growers who are not flat fumigating with methyl bromide + chloropicrin should consider using a high rate of chloropicrin under impermeable film.  This likely will not be as good a treatment as the mix of methyl bromide + chloropicrin used in the past, but it is the next best soil treatment solution.

Reducing stress to the plants: The diseases caused by both Macrophomina and Fusarium develop earlier, more rapidly, and more severely if plants are stressed.  Strawberries that are under-chilled or subject to irrigation deficits, fertility shortfalls, and/or pest issues (such as mites) can succumb fairly rapidly, while those perfectly managed can withstand disease for a longer time. Growers wanting to reduce their diseases losses from here on out will need to play a tight defensive game and address plant stress factors in a timely manner.

Not disturbing the existing bed: The in-field spread of both Macrophomina and Fusarium is mainly accomplished by tillage and other procedures that move soil around.  Because neither pathogen makes airborne spores (such as those made by powdery mildew and gray mold pathogens) or swimming zoospores found in soil water (produced by Phytophthora), the spread of inoculum is only by physical movement of the soil. Presumably, beds remaining intact and in place, as they would be for second year strawberries or other system of minimal tillage, will keep the pathogen from being spread to non-infested parts of the field.

This situation has been observed locally. In 2013, a strawberry field had significant Macrophomina outbreaks in certain parts of the field. Held over for a second year, the dead areas were replanted and again developed disease in those sections; however, second year plants that were healthy in 2013 were mostly healthy in 2014. While growing second year strawberries is not being recommended, this type of situation demonstrates the key role of soil movement in disease epidemiology.

Sanitation: Sanitation is critical for limiting the spread of Macrophomina and Fusarium. Tractors, tillage equipment, and irrigation pipes moving from infested fields should be cleaned.  Remember too that a strawberry field that had significant dieback two years ago and is now planted to lettuce or another crop, likely still has plenty of Fusarium or Macrophomina around.  It is a good practice for all of us to pay attention to where we have been and clean up if you are coming out of an infested field. 

Having the Right Attitude and Accept the Changing Reality: In this environment of new diseases and reduced to no availability of good fumigants, those able to keep open minds and adopt new practices stand the best chance to weather the storm from these new pathogens.  Growers and agricultural professionals of all stripes MUST adapt to this new era.  Go to meetings, keep up to date on the latest research, talk with reputable professionals and be ready to make the changes necessary to keep your crop the most productive it can possibly be.

Nice little article describing the collaboration between me and Steven Koike on solving disease and physiological problems in the strawberry industry.  You name it-  we take it on, solve it and post what we found out in this space so everybody can learn along with us.

http://ucanr.edu/delivers/?impact=951&delivers=1

2014 Plant Disease Seminar

Thursday, November 13, 2014

8:00 a.m. to 12:00 p.m.

**County of Monterey Agricultural Center— Conference Room**

1432 Abbott Street, Salinas, California

8:00 – 8:30            Registration for morning session (no charge).

8:30 – 9:00            2014 plant disease developments in coastal California

                              Steven Koike. UC Cooperative Extension, Monterey

9:00 – 9:30            Weeds as pathogen reservoirs: INSV case study

                              Richard Smith. UC Cooperative Extension, Monterey

9:30 – 10:00          Iris yellow spot virus of onion: coastal & statewide update

                              Tom Turini. UC Cooperative Extension, Fresno

10:00 – 10:30        Break: Sponsored by CAPCA, Monterey Bay Chapter

10:30 – 11:00        Challenges of spinach seed production

                              Jay Schafer.

11:00 – 11:30       Biology of Fusarium oxysporum & management of

                              Fusarium wilt of lettuce

                              Tom Gordon, University of California at Davis       

11:30 – 12:00        Pre-plant soil preparation post methyl bromide:

                              where are we going from here?

                              Mark Bolda. UC Cooperative Extension, Santa Cruz

Continuing education credits are requested. Call ahead (at least 24 hrs.) for special needs arrangements; efforts will be made to accommodate full participation. For more information, contact Steven Koike (831-759-7350; 1432 Abbott Street, Salinas, CA 93901) or visit our website at http://cemonterey.ucdavis.edu.

Requirement from California DPR: Bring your license or certificate card to the meeting for verification when signing in for continuing education units.

Nice introductory video from Dr. Chieri Kubota with the Arizona Controlled Environment Center at the University of Arizona.

Lots of advantages in Arizona for hydroponics - no pesticides, winter production, less water use and SAME DAY delivery from the greenhouse to the store.   At five bucks a pint not that cheap though.

http://www.youtube.com/watch?v=C1oSypOSrfU&list=PLE09E9F4C664C0F2B

Interesting history of strawberry production in Arizona, including the cultivation of an everbearing variety all the way back in 1893.