Marilyn did you read my post about the use of pheomones to control Olive fly??
They are available by mail order from the UK. Not sure about the species and not sure if they would work in a med summer. I attach an MGS report for your interest. david
MYCORRHIZAL PREPARATIONS: A STUDY
The Scientific Committee
It has become increasingly difficult to read a gardening magazine or view an article on the internet without seeing reference to the benefits of mycorrhizal-fungi (m-f). The mediterranean gardener may be asking him or herself the following questions; What are these fungi and what do they do? How do they work? How are they employed? Where can they be obtained? Would they be of use in an ornamental or culinary garden? Do they do what it says on the tin? As members of the MGS Scientific Committee (SC) we hope that we may be able to throw a little light onto some of these questions.
What are m-f? These organisms are referred to as beneficial soil fungi and as such are not to be confused with the non-beneficial, destructive fungi such as Armillaria mellea or A. gallica more commonly known as Honey Fungus. It has been estimated that around 70% of the biomass in undisturbed soils consists of mycorrhizal type of organisms. However, it has been shown that events which substantially disturb the soil, such as compaction, erosion, building operations and the use of soil-less mixtures can result in the reduction or even the elimination of these beneficial fungi.
What do they do? Around 90% of plant species form a mutual or symbiotic relationship with m-f. These “hybrid” materials generally fall into two main groups; those resulting in an external modification of the root tissues are termed ectomycorrhizae, while those forming structures within the root are called endomycorrhizae or arbuscular mycorrhizae.
The vast majority of commercially grown tree species worldwide form ectomycorrhizae whilst the most important agricultural and horticultural plants form endomycorrhizae. There are of course some plants that do not rely on mycorrhizal development in their natural environment and examples of these being found in the plants that rapidly develop following events that destroy or disturb existing mycorrhizal fungi, such as fire and soil disturbance.
How do they work? The m-f colonises the roots and extends far out into the surrounding soil greatly increasing the surface absorbing area of the roots. The colonised root system is termed a mycorrhiza and is fundamental to the establishment of the plant. The mycorrhizae supply water and nutrients for growth and in turn receive sugars and other materials from the host plant. In addition they release chemicals into the soil which help to free-up many difficult to absorb trace elements. The plants are therefore under less drought stress and more able to resist disease attack. Indeed there is evidence that the chemicals released can also suppress and kill disease organisms in the root zone. Mycorrhizal filaments also produce humic compounds leading to an improvement in the soil porosity. This improvement leads in turn to increased aeration, water movement and hence root growth and distribution.
How are they employed? Products available to the amateur gardener can be either sprinkled into the bottom of a planting hole in direct contact with the naked roots, along a seed drill or a pinch below the position of a seed or bulb. In the latter two cases a thin layer of soil is used to cover the material before sowing or planting as normal. As the roots grow they will penetrate the fungal layer and become colonised.
The products commercially available contain both ecto and endo m-f on an inert mineral carrier. As such they can be used as a general-purpose treatment on a wide range of plants. However the following acid loving plants are not recommended for treatment - rhododendrons, azaleas, heathers, cranberries and blueberries as well as brassicas.
To facilitate their application to large bare rooted plants, they may be dipped into a gel preparation containing the fungi thereby improving the coverage of the roots.
Where can they be obtained? At the present time they can take a little tracking down and do not seem to be widely available in the normal outlets for the amateur gardener. As usual the internet and online suppliers proved the most convenient way of obtaining a supply for private use.
Are they useful in an ornamental or culinary garden? In order to try and answer this particular question members of the MGS SC agreed to conduct a limited trial over the winter period in the Languedoc Roussillon region of France using a winter crop of Valerianella locusta more commonly known as mâche, corn salad or lamb’s lettuce.
The following treatments were compared:
1. Mâche treated with “Rootgrow” following the manufacturer`s recommendations.
2. Mâche untreated
“Rootgrow"TM is produced under licence from the Royal Horticultural Society by Plantworks® Ltd UK.
Test plants: mâche grown in peat blocks/plugs.Twenty plugs were dipped in the gel containing the m-f and then left to drain for 10 minutes. 20 plugs were left untreated. The plugs were then planted outdoors in open ground in alternate rows. The trial was repeated at three different locations in the Languedoc over the period from late October to the end of January 2010 approximately eleven weeks.
Assessments and harvesting: Each rosette of plants was first assessed by visually ranking the rosettes as small, average and large and scored 1, 2 or 3, the score was totaled. The crop was then harvested by cutting at the base of the rosette and the foliage weighed. This weight was then divided by the number of plugs to arrive at a weight per plug.
Results: location 1 location 2 location 3
T UT T UT T UT
No of plugs 23 22 20 20 19 19
Visual score 48 35 44 33 41 39.5
Total weight g 251 159 755 705 372 452
Visual score/ plug 2.1 1.6 2.2 1.6 2.16 2.1
Weight / plug g 10.9 10.0 37.7 35.2 19.5 23.
At all locations the visual score for the treated mâche indicated more robust plant compared to the untreated and this was confirmed by higher yields except at location 3. At this location the plants were washed before weighing and this could have contributed to a higher weight of untreated plants.
Conclusion: This trial indicates a small 5-10% yield increase for mâche grown under winter conditions; further studies would be required to confirm this result on different species of mediterranean plants grown under spring or summer conditions and over a longer period.
Directions for use for “Rootgrow”:
1. In a suitable container add 1 litre of water.
2. Sprinkle the white gel powder into the water and stir well.
3. Leave for 5 mins and then add the Rootgrow granules and stir until the granules are evenly suspended in the thick liquid (wallpaper paste consistency).
4. Dip the roots of the plant or cell into the gel and allow coverage of the whole root system. Say 5 minutes. If the gel seems too thick add up to 250mls more of water.
5. Remove the plants or cell, drain briefly and plant immediately