The UK market is very important to Kenyan exporters and the
goal posts have been clearly defined by leading UK supermarkets such as Marks
and Spencer which have standards prohibiting their suppliers from using certain
pesticides, even though their use is legally permitted (PN54, page 3). Other
standards, such as the European retailers’ EUREPGAP audits for vegetables and
flowers, have a strong emphasis on pesticide reduction and the adoption of
Integrated Pest Management. Nowadays, if you want to impress a customer, you
have to wheel out the IPM programme for them to inspect!
European growers have had access to commercially produced
biological control agents (natural enemies which feed on pests) for decades,
although the use of these alternative methods has been largely limited to
protected salad crops in greenhouses, such as tomatoes, cucumbers and peppers,
and soft fruit. The biocontrol industry also provides training on how to use
natural enemies to replace reliance on pesticides and there are experienced
consultants able to provide commercial advice on biological crop protection in
organic and IPM systems.
The situation in most of Africa is very different and access
to commercially available natural enemies has been extremely limited, unlike
Europe and the US where growers can pick up the phone and receive a delivery the
following day. IPM training courses showing growers how to identify local
beneficial insects are of little practical value if the grower does not have
enough of them in the right place at the right time. Access to mass-reared
natural enemies is therefore essential to kick-starting IPM strategies in
commercial horticulture.
Enabling environment
After a slow start, Kenyan regulators have now kept
pace with the needs of the export industry by providing an enabling environment
for the adoption of IPM and the use of biological control. Funding from the
UK’s Department for International Development enabled the Pest Control
Products Board, which registers crop protection agents, to amend the
registration requirements for natural enemies, biopesticides, botanical
pesticides and semiochemicals, to streamline procedures and put these products
on the market quickly. An international forum of registration experts from the
EU guided delegates at the Kenyan Biopesticides Registration Workshop in June
2003, to devise Legal Notices, which would be easy to adopt and implement,
without posing unnecessary hurdles, costs and delays. In contrast, regulatory
authorities in the EU have cumbersome procedures which are currently preventing
alternatives to pesticides from being made available to growers (see PN 59, page
10). Many other African countries are now following Kenya’s example.
What has been the impetus in Kenya? The industry is fiercely
competitive and where one leads, the others follow. In 2000, one of the leading
vegetable and fruit exporters, Flamingo Holdings, began investing in IPM. Louise
Labuschagne, an independent IPM consultant from the UK, and former Professor of
Horticulture, Dr Henry Wainwright, worked with the company to develop mass
rearing capabilities and IPM protocols for vegetable and flower crops.
Organophosphates, organochlorines and carbamates were virtually eliminated from
the outdoor vegetable production in less than three years. As a result, Flamingo
Holdings was given an environment award by the UK Worshipful Company of
Fruiterers for the work carried out in Kenya. In January 2004, the Real IPM
Company was formed to provide services to growers throughout Africa and
elsewhere to have direct access to IPM training and consultancy to achieve
substantial pesticide reductions.
Achievements in biocontrol
Biological control of leafminer
Leafminer can be a devastating pest of legumes and
salads as well as some flower crops. Leafminer larvae tunnel through leaf
tissue, causing serious cosmetic damage, while the whole plant can die from
severe leafminer attacks. Furthermore, Liriomyza huidobriensis and other
related species are notifiable pests in the EU, meaning official controls to
avoid its spread. Five years ago, exporters were facing severe control problems
with this pest, with insufficient tractor-time to get enough sprays onto the
crop to keep the pest at bay. Crops were destroyed and yield devastated, in
spite of the intensive applications of insecticides, including deltamethrin and
thiocyclam.
There is however, a tiny parasitic wasp Diglyphus isaea that
attacks the leafminer larvae. Unbeknown to growers, Diglyphus was already
present in the field but the sprays being applied were killing it, so it could
not make a full contribution to crop protection. A system was set up to harvest Diglyphus
from crop debris and harvested Diglyphus was applied to young crops to
protect from leaf miner without using pesticides. Systems were also set up to
mass rear Diglyphus, as the amounts harvested from crop debris began to
diminish. Introduction rates to field grown legumes were about 12,000 per
hectare over a six-week period. This would have been prohibitively expensive if Diglyphus
had been purchased at EU prices of £22.50 per 250 adults (£1,080 per hectare).
Within a year, no sprays needed to be applied to leafminer because Diglyphus
was controlling the pest over many hundreds of hectares. Even the introduction
rates of Diglyphus required diminished.
However, many farms in Kenya are not aware of these
achievements and leafminer continues to be intercepted on Kenyan produce
exported to the EU. This situation should change with more training and
consultancy awareness-raising throughout East Africa.
Replacing acaricides in roses
It is often suggested, as an excuse for not using IPM
in flower crops, that the risk of cosmetic damage is too high and that
biological controls are not robust enough to protect the crop. The Real IPM
Company’s recent experience with large-scale growers of roses shows that this
is not the case.
Acaricides account for about half of all the agrochemicals
applied to roses. The Kenyan flower industry has suffered damning criticism from
the International Human Rights Commission for alleged excessive use of
pesticides in flower crops and the associated worker welfare issues. However,
there is now a practical and economic option to pesticides for the control of
spider mite in roses with the use of Phytoseiulus persimilis (a predatory
mite for the control of red spider mite). The Real IPM advisors have been at the
forefront of this development work that could halve the amount of pesticides
used in rose production.
The predatory mite is indigenous in Kenya and can be
mass-reared locally, which makes it much more economic to use. The first company
in Kenya to successfully implement the scouting systems and predator
introduction strategies was Enkasiti Ltd, based in Thika. Enkasiti now has 29
hectares of export roses, which are using IPM for spider mite control.
Close on the heels of Enkasiti, Homegrown and Redlands have
recently achieved similar successes. Support services to rose growers range from
development of IPM scouting teams and analysis of scouting data to farm
strategic plans for reduction of acaricides. This complements specialist
consultancy services in the development of on-farm Phytoseiulus
production capability. Together, these services can drastically reduce annual
crop protection input costs within 12 months by eliminating reliance on
acaricides, such as the OP demeton-S-methyl (WHO Class Ib – highly hazardous)
and the organochlorine dicofol.
The Real IPM Company runs a training programme to enable
export growers to mass rear their own natural enemies, making the use of large
numbers of beneficial insects economically viable and readily accessible. In
addition to Phytoseiulus and Diglyphus, mass-rearing of Encarsia
(for whitefly), Aphidius (for aphids), Trichogramma (for
caterpillars), Orius (for thrip) and other beneficial insects is now operational
in Kenya. The EU-funded Pesticide Initiative Programme (PIP), set up to enable
exporters in developing countries to comply with stricter European Maximum
Residue Levels, has been instrumental in supporting horticulture companies to
obtain training and consultancy services in IPM.
Louise Labuschagne is Director of the The Real IPM Company, based in Thika, Kenya and can be contacted on info@realipm.com or website www.realipm.com
[This article first appeared in Pesticides News No. 64, June 2004, pages 14-15]