Re: [tomato] Mycorrhizal Fungi Experiments

connie hoy (
Wed, 18 Feb 1998 20:30:22 -0800

I was fascinated with your report and appreciate your sharing it with
One question as to flavor,did you notice any flavor change with the
inoculated plants??
Where did you obtain your Mycorrhizal fungi inoculant.
Again this was very interesting and thanks.
Connie Hoy

Doreen Howard wrote:
> Louis wanted mycorrhizal fungi talk!!  Here's what I did with VAM
> strain mycorrhizae in 1997.
> --------------------------------------------------------
> Experiments with Mycorrhizal Fungi and Tomatoes
> (Heirloom and Hybrids)
> 1997
> Doreen Howard
> Premise:  Tomato plants inoculated with mycorrhizal (VAM) fungi will
> outproduce control tomato plants that are not inoculated.
> Conditions:  This experiment took place in Angleton, Texas, which is 42
> miles south of Houston, near the Gulf of Mexico.  The USDA climate zone is
> 9, but the microclimate which is moderated by sea breezes is actually zone
> 9B.  The first frost date is about Dec. 10 and the last frost date is March
> 5.  However, freezes occur usually in only one out of
> three years.  Temperate weather in which tomatoes can set fruit is between
> March 5 and approximately April 25.  After that date, nightly temperatures
> climb above 75 degrees. Annual rainfall is about 65 inches.  Humidity
> averages 75-95% year-round.  Naturally occuring soil is gumbo clay.
> Subjects:  The following tomato varieties were used in this experiment:
>         Hybrids:  Carnival, Odoriko.
>         Heirlooms:  Wonder Lite, Green Zebra, Black Plum, Silvery Fir         Tree,
> Striped
>         German, Purple Smudge, Schimmerg Stoo, Garden Peach, Gurnsey
> Island, White Bush, Southern Night.
> Method:  All tomato plants were grown from seed in flats.  Half were
> inoculated with the fungi when potted up to 2-inch containers, approximately
> two weeks after sowing. The other half were not.  Of the inoculated half, 50
> percent were fertilized with pelleted fish
> meal and trace element volcanic minerals and 50 percent were fertilized with
> Osmocote (14-14-14 with trace elements).  A pinch of inoculant, 1 teaspoon
> pelleted fish meal (9-3-5) with a pinch of trace element volcanic minerals
> or a pinch of inoculant and 1 teaspoon of Osmocote were placed under each
> transplant.  The control plants were potted with l
> teaspoon of pelleted fish meal and a pinch of trace element volcanic minerals.
> Transplants were allowed to grow under horticulture lights and outdoors in a
> sheltered area for four weeks.  Most were potted up into larger containers
> twice, because of rapid growth.  The inoculated transplants (both the fish
> meal and Osmocote fertilized ones) were markedly sturdier and bushier than
> the control plants.  At the end of this six week
> period some of the inoculated plants had flowers on them.
> On March 5, 1997, all plants were set out in beds that were 5 feet apart and
> separated by clay soil overlaid with St. Augustine turf.  The control plants
> were set in one bed that was 4 feet by 28 feet; plants were spaced three
> feet apart.  A quarter cup of pelleted fish meal and a dusting of trace
> element volcanic minerals were placed in planting holes. Plants were caged,
> and the cages were wrapped with Reemay for weather and blight protection.
> The inoculated plants were set in two beds--each one was 4 feet by 16 feet.
> Osmocote-fertilized plants went into one bed, and a quarter cup of Osmocote
> was added to each planting hole.  Fish meal-fertilized plants went into the
> other bed, and a quarter cup of
> pelleted fish meal and a dusting of ttrace element volcanic minerals were
> put in each planting hole.  All inoculated plants were caged, and the cages
> were wrapped with Reemay.
> The soil in all three beds was identical--composed of naturally occuring
> clay soil, peat moss, compost, composted cow manure, shredded oak leaves and
> alfalfa pellets added at the rate of 5 pounds per bed.  Beds were raised 8
> inches above the grade and bordered with cement blocks.
> The only other care given to plants (other than what is mentioned under the
> observation section below) was a prophylactic weekly foliar spray of Neem
> oil for early blight and other fungal diseases.  The foliar spray was
> applied for six weeks. Watering was not necessary, because rainfall was more
> than sufficient.
> Observations:  Spring weather in South Texas was unusually cool .  Soil
> temperature reflected that.  Cool nights (45 degrees) were recorded well
> into April, when nightly temperatures usually reach into the 70's by month's
> end.
> 3/5/97          When plants were pulled out of pots to be set in the ground, white
> fuzzy material was observed covering the outer edges of root balls. (Slides
> available).
> 3/21/97 First fruit set on inoculated Southern Night heirloom plant.
> 3/24/97 First fruit set on inoculated Odoriko hybrid plant.
> 4/9/97  First fruit set on control Southern Night heirloom plant.
> 4/10/97 First fruit set on control Odoriko hybrid plant.
> 4/11/97 Control plants are a deeper green in color than inoculated ones.
> Controls look healthier.  Inoculated Osmocote plants look better
> than the fish meal ones.  The fish meal fertilized plants have
> purplish leaves that seem to indicate phosporous deficiency, and
> their growth has stopped.  Nights are in the low 50's.
> 4/14/97 Purple coloring of leaves and blossoms is more pronounced on
> inoculated fish meal-fed plants.  Other inoculated Osmocote and
> control plants all look fine.  Fish meal plants are each fed a
> gallon of water with 1 tablespoon of 15-30-15 Miracle Gro         dissolved
> in it.
> 4/18/97 Purple color has disappeared from affected plants and growth has
> resumed.
> 5/1/97  Picked first tomato from inoculated Southern Night plant--56 days
> after setting out the transplant. This is listed as an 85-day         tomato.
> 5/8/97  Picked first inoculated Odoriko hybrid tomato--61 days after
> transplanting. It's listed as a 76 day tomato.
> 5/15/97 Early blight has set in on all plants, despite the prophylatic
> treatment.
> 5/20/97 Harvest is in full swing, and early blight is pervasive.  Control
> plants are complete brown and barely surviving to ripen their
> fruit.  Inoculated plants are brown and  look nearly dead, except
> for the top foot or so of green foliage.  However, they are
> loaded with fruit, and the fruit is ripening.  It's a strange         sight.
> 5/24/97 Picked first control Southern Night tomato--79 days after
> transplanting
> 6/5/97  Last tomato picked and heavily diseased plants were pulled up.
> Two inoculated plants that were situated next to a patch of
> Truimph de Farcy filet beans have nodules on their roots.  At
> first, they appeared to be nematodes, but nematodes have never
> been recorded in this garden or was there evidence of nematodes
> anywhere else in the garden.
> 6/5/97  A general observation: most every blossom on inoculated plants
> set fruit, but fruit size was smaller than in previous years.
> Plants were grown from seeds saved from previous crops; some
> varieties have grown in this garden three years.  So the         observation
> of small fruit size is based on long  term
>         evaluation.  Control fruit was of average size for their various
> varieties.
>         Over 500 pounds of fruit was harvest from 21 plants. One of the
> control plants died, and control plants of every variety tested         were
> not planted.
> Yields:
>                         Inoculated                      Control
> Wonder Lite             122 fruit                       29 fruit
> Green Zebra             85                              26
> Black Plum              314                             Not Planted
> Odoriko                 82                              29
> Silvery Fir Tree        75                              Not Planted
> Striped German           12                             Plant Died
> Purple Smudge             25                            7
> Schimmerg Stoo           118                            28
> Garden Peach            103                             48
> Gurnsey Island          175                             71
> Carnival                66                              Not Planted
> White Bush              36                              13
> Southern Night          74                              34
> Conclusions:
> Mycorrhizial fungi appears to increase the fruit yield of tomato plants and
> helps plants produce in adverse conditions such as heavy blight damage.
> Fruit on inoculated plants matured sooner that normally expected.  Total
> weight and number of fruit from inoculated plants was much higher than the
> total weight and number of control fruit.  But, individual fruit from
> inoculated plants were smaller than the average stated in literature and
> from previous growing experience.
> The nodules found on roots of several inoculated plants may have been due to
> a transfer of nitrogen-fixing bacteria from surrounding legumes.  I cite
> "Humic, Fulvic and Microbial Balance: ORGANIC SOIL CONDITIONING" by William
> R. Jackson, PhD., p. 550, "Promotion of nodulation of symbiotic
> nitrogen-fixing bacteria such as rhizobium, as reported by Mosse et al."
> In cool soil where microbial activity is sluggish, plants appeared to
> benefit from Osmocote to provide the nutrition they needed for initial
> grown.  Organic fish meal pellets left plants showing signs of phorphorous
> and nitrogen deficiencies, and Miracle Gro had to be
> applied to supplement the fish meal.