liter of neem oil is used for preparing about 17-18 backpacks of fumigation
(of 15 liters each).|
NEEM IN AGRICULTURE AND ECOLOGICAL GARDENING
Farmers and gardeners use neem oil as an ecological
insecticide and fungicide in order to keep away pests such as aphids, spider
mites and white fly. Neem oil effectively protects crops from fungi, such as
rust, powdery mildew and downy mildew infections. This protection is not
only as a preventative, but also as a curative treatment. This way, when a
plant is affected by any of these pests, the ideal method would be the use
of neem oil as a treatment of contact, based on the fumigation of leaves,
branches and trunk; as well as irrigation, that will make the effect of
systemic treatment, being absorbed from roots to all parts of the plant.
In the case of insect pests (e.g. aphids) you should not
expect to find bodies, since it does not kill by contact, but it eliminates
the population, preventing from feeding and reproduce. Therefore it will not
affect to non phytophagous organisms, so it has no effect on pollinators
like bees or natural predators of pests which may have been introduced as
Other advantages deriving from the use of neem oil in
organic farming is the foliar fertilizer effect that the fumigation with
this product has. Neem fumigated, or dissolved directly in the field,
provides nitrogen and nutrients to the plants and trees, and often shows a
systemic effect whereby its effects spread from the root system to the
We prove the effectiveness of this ecological treatment
in a field of our property during the spring and summer of 2010, and the
results were very satisfactory. The location of the field is in the province
of Pontevedra - Spain, where is the production of the famous wine Albariño.
This is a very damp area, which is frequently attacked by diseases of fungi
(especially downy mildew and botrytis). Therefore the winemakers are in need
of sulfate vineyards every fifteen days, or less if the summer is humid. All
this use of chemical treatments is not only harmful to plants, which
increasingly become weaker and dependent on chemical treatments, that
shortens their life. But also, in the medium and long term, it is very
harmful for people, who gradually go polluting their land and groundwater,
as well as filling the air with pollutants, which are inevitably breathed by
people and animals. In addition, there is the resistance that pathogens
develop against fungicides, which also causes that they are increasingly
less effective, and have to be replaced by new ones every time. It should be
noted that neem oil does not cause resistance by pests.
In our experience, we replaced all the fungicides and
sulfates, both in the vineyard and in a garden planted of fruit trees. And
we limited the application to spraying neem oil every 20 days, instead of
the 10 or 15 employed by vine-growers in the area with chemical treatments.
2010 spring was very wet, so there were continuous attacks of pests. Even,
some growers lost a part of their production. We also suffered some attacks
in the vineyard, but not, in fruit trees. However, no vine stock was
especially damaged, as when we discovered that it was infected, as well as
foliar treatment, we added irrigation with the same mixture of neem oil, so,
although some branches that finished drying were lost, all the vine stocks,
without exception, eventually got recovered. In addition, the general
appearance of the plants was much more healthy and lustrous than in previous
years, when we always had the leaves of the vine stocks covered with typical
Both our own experiences, as the led out by universities
in United States and India over the past two decades, lead us to recommend,
without a doubt, the use of neem oil for all types of agricultural
treatments (vineyards, orchards, gardens...) and gardening. Fortunately,
every time there are more suppliers that are starting to provide in the West
products derived from the "Tree of the Millennium". Name given
to the neem tree by United Nations, which will make prices keep lowering.
NEEM OIL AND SODIUM/POTASSIUM BICARBONATE
Research carried out for three years by Dr. R. Kenneth
Horst, researcher of the Cornell University of New York, at the end of the
Decade of the eighties, showed the extraordinary effectiveness of
bicarbonate in the fight against mildew, oidium, BOTRYTIS, alternaria, as
well as against the disease called "black spot", which usually affects the
One of the reasons of this efficiency is that the baking soda
reduces acidity of the surface of the leaves, preventing that the fungus
reproduces, since these fungi need an acidic environment to live.
Several studies and experiments in the United States and
Europe during the next two decades, confirmed and extended the results
obtained by Dr. Horst, indicating that, in the specific fight against
mildew, potassium bicarbonate was somewhat more effective than the sodium.
But that, if the baking soda was added to a mixture of surfactant (liquid
soap or wetting agent) more horticultural oil (such as neem oil), this
mixture not only protected, but eliminated the disease within two or three
We have recently begun to apply this combination of wetting +
neem oil + bicarbonate, in one of our fields, where mildew is an endemic
disease that attacks every year, and we have also reached the conclusion
that this mixture provides better results than just the application of
wetting + neem oil, especially if the plants have already been attacked by
the fungus. Therefore we recommend its use for all those who
suffer from this type of fungal diseases in their plants. In the following
section, applications, we explain the proportions to mix.
There are two kinds of baking soda which can be used, and
both are very effective.
• Sodium bicarbonate. It is the one always used as a stomach antacid.
You can buy it at cheap prices at any supermarket or drugstore, apart from
pharmacies. It has the disadvantage that in the long term it can leave
undesirable residues into the soil, in the form of salts, so you should not
use in irrigation.
• Potassium bicarbonate. It is more difficult to find, and its price
is somewhat higher, but it is more beneficial for the plant and its
environment, since it does not only have fungicide action, but also of
foliar fertilizer of potassium; leaves no residue because the plant absorbs
it as a nutrient, which also strengthens it to resist the attacks of the
fungi. Well known is that the potassium phosphite is used as a fungicide,
even without combining it with other products.
Sodium bicarbonate can be used to improve the results of neem oil, but if
you want to try with the potassium, you may purchase through our online
SOLUBILITY OF NEEM OIL IN HARD WATERS
Some of our customers have indicated that they find it
difficult to dilute the neem oil in the water, even using a good emulsifier.
The problem is not due to neem oil, nor the use of the wetting or potassium
soap, but the hardness of the water used to make the mixture. The
dissolution of the oil must be done perfectly using cold water, but if the
water is very hard (calcified) lumps are formed and it is even possible that
the mixture does not carry out. This is not usual, but our customers have
told us some case.
The ideal thing for these extreme situations would be the use
of rain water, which is also the best for watering plants. Hard waters are
more harmful to plants, for its high content in salts of calcium and
magnesium, which end up accumulating on the ground.
To facilitate the solubility of neem oil, we sell a potassium
soap special for these uses. Anyway,
with extremely hard water, if these cannot be substituted by rain water or
purified water (soft), the best solution is to increase the amount of liquid
soap (at least 5 ml of liquid soap per liter of water). Or also, if it is
only for a small garden or flower pots, you could buy bottles of distilled
water sold in hypermarkets at low prices.
- Add 3 to 5 ml of emulsifier (*) per liter of water, mix well and then add
3 to 5 ml of pure neem oil per liter of water, mix again and is now ready to
be sprayed. It is recommended to use within 24 hours so that it does not
lose its properties.
(*) Any liquid soap bought at the supermarket can serve as emulsifier,
although it is preferable to use an organic liquid soap. In our online
store, you can purchase liquid potassium soap, crafted, 100% eco-friendly.
It will not only facilitate the solubility of neem oil, but also favour the
elimination of harmful insects.
- To increase the effectiveness in the treatment of fungal diseases
(downy mildew, powdery mildew, botrytis, alternaria, black spot...), add,
after making the previous mixture, between 2 and 3 g of sodium or potassium,
bicarbonate per liter of water, and mix again. Although they are not the
same units, it would serve the same measuring cup. For example, if you add
50 ml of neem oil in ten liters of water, in the same glass you would
measure about 30 gr of potassium bicarbonate.
- As prevention, make a spray every 15 to 20 days, depending on the
humidity of the area.
- To control pests already present. Apply the spray every 4 or 5
days, until the complete elimination of the plague, and then return to the
normal periodicity. In the case of badly affected plants, combine spraying
(treatment of contact), with the irrigation of the same product (systemic
therapy). In case of using sodium bicarbonate, irrigation is not recommended
because salts could be accumulated in the ground, in the long term.
You should fumigate preferably in the first hour of the day or in the
evening, near the sunset, since azadirachtin loses properties when it is
applied in full sun, even if this was intense, it could burn the surface of
the leaves, by the "magnifying glass" effect of water droplets.