Here is the first decision you need to make if you are following a chemical control vs. organic path.
Physical weed control
Young trees are best kept free of weeds with weed mats and plastic mulches, but they cease to be effective and actually delay the growth if used for more than the first three years of planting. Then the ground becomes a target for weed seeds blown into the area.
Mechanical disturbance around the tree of weeds has the added value of loosening the soil for new truffles to have less soil compaction and access to air and moisture.
It had been accepted that the brulè area around the tree was a ‘do-not-disturb’ zone because you would destroy the spreading roots, but shallow tilling is now considered not only safe but beneficial (soil aeration and spore spreading).
Here is a power harrow used in Australian vineyards that is also being used widely in Spain for truffles. It is dependent on staking so that the sensor wire can trigger the withdrawal of the tillers from the row.
There is also a purpose built truffle cultivator which also implements the option of side shifting in between the trees. These would need to be used from a young age in the orchard to train the roots to run deeper. For more mature plantings there would need to be a gradual introduction.
Chemical Weed control
There are NO recommendations by APVM for herbicides specifically for truffles. All the herbicides currently used in truffière weed management are tested for grain and cereal crops not for root crops like potatoes or tubers. See those Residue trials report here.
We do know that herbicides change the soil bacteria around the truffles and there is growing evidence that the bacteria have a lot to do with the aroma of the truffle. In our fertile soils weeds will be a problem that new growers will struggle with. If you think that you can distinguish your produce with an organic certification to obtain a premium price, this will leave you with the only option being mechanical disruption of the area around the trees in the top 10 cms. This will certainly damage truffles and roots if they are forced to the surface by your soil conditions.
In response to a member email
I was wanting some advice on control of dock. We have a big problem around our truffle trees. In July we manually dug them out (as well as possibly some truffles) only to find them all come back in September. We don’t want to disturb the soil around the trees again. What are your thoughts on using MCPA in the brulee area? Roundup isn’t controlling the dock at all. Are others using Roundup in the brulé area for control of other weeds? I’m hearing that it has a mild fungicide in it. I only know one other truffle grower in Tasmania and they don’t use Roundup and they also don’t have a dock problem. The dock plants are currently going to seed so I would appreciate any advice as soon as possible.
Rosemary Collins
MCPA may not be very effective as it is generally used when young weeds are emerging. I use Basta (Glufosinate) on all weeds either in or outside the brûlé during the truffles active growth phase (October – May). Basta should be sprayed to cover the foliage thoroughly with a fine mist however avoid run off onto the soil. Basta shuts the plant down within a few days without translocation of more than a couple of % into the root system.
It is non selective so will kill whatever it hits when it comes into contact with the green part (foliage or young bark) of a plant. It is also used on mature Hazelnuts as a sucker control.
Noel Fitzpatrick www.truffleharvest.com.au
Links.
Basta Non-selective Herbicide at the APVMA website updated 19 Feb 2013
How to use this information: All chemicals used in agriculture need a certification from the APVMA– Australian Pesticides and Veterinary Medicines Authority. Products tested have an original publication date, and any variations or subsequent warnings appear as a Trade Advice Notice. There is a Gazette that has updated information as it appears. You can subscribe for emailed copies here.
There are NO recommendations by APVM for herbicides specifically for truffles. All the herbicides currently used in truffière weed management are tested for grain and cereal crops not for root crops like potatoes or tubers. See the Residue trials report here.
The offset power harrow seems rather disruptive. The same company Rinieri has a purpose built truffle cultivator, however it would best be used from initial planting date to keep root development at depth, assuming initial cultivation incorporated lime sufficiently deep.
https://www.youtube.com/watch?v=Bx0xFR7bhGc