nematode control using marigolds
- To: Multiple recipients of list <i*@rt66.com>
- Subject: nematode control using marigolds
- From: s*@aristotle.net (J. Michael, Celia or Ben Storey)
- Date: Sat, 15 Mar 1997 10:05:17 -0700 (MST)
The March/April issue of "National Gardening" carries a brief article about
Dutch experiments to determine which variety of marigold offers the most
effective natural nematocide (methyl bromide will soon be banned as a
fumigant). The author, Shepherd Ogden, doesn't say where these studies were
conducted in the Netherlands, but he claims more than 800 cultivars were
tested. Cover crops were planted and left in place for one complete season,
weed free. The plants were not tilled under. At the end of the season, the
plants were removed and the soil retested for nematode infestation.
The winning nematode-killer was a French marigold, Tagetes patula "Single
Gold." This plant apparently dispatched 99 percent of Pratylenchus
penetrans. Protection was adequate to support return of regular plantings
for 2 to 3 years.
Here is my question, or questions. Ogden mentions only results against
Pratylenchus, the common meadow nematode. "World of Iris" suggests that
nematode is not a problem for iris growers, but Meloidogyne is.
Does anyone know more about these Dutch trials? Did they get results for
Meloidogyne?
And has anyone tried planting T. patula as a cover crop for one season?
Ogden noted that just planting a few marigolds among regular plants will
not work, nor will tilling the plants into the soil like green manure. The
nematocide effect only operates when the nematodes attack living marigold
roots. The microscopic bad guy attacks, and the root releases ozone which
kills the nematode.
I don't have a nematode problem in my bed today, but am planning ahead a
few years to the season when I will move the irises out to rest that site.
Marigolds have such a long growing season in Arkansas, I could see planting
a fall-winter crop as soil prep for a new bed to be laid in the spring or
summer, or a spring bed.
W. Atlee Burpee has "Single Gold" T. patula listed as "Nema-gone" at $8 the
half-ounce, which is enough seed to cover 1,000 sq ft.
W. Atlee Burpee
Garden Road
Warminster, PA 18077
1 (800) 888-1447
What do you guys think? Is this a useful plant for reconditioning iris
beds? If not, is there another marigold that would be better?
celia
storey@aristotle.net
Little Rock, Arkansas USDA Zone 7b ... where we are experiencing the
dreaded annual late freeze
AIS Region 22
