Environmental Engineering Reference
In-Depth Information
(Kaine 1976). In this regard, the Department of the Crop Protection Division of the Ministry
of Agriculture and the Veterinary Department have played a prominent role in generating pub-
lic awareness about the selection, purchase and application of pesticides. Both departments
have also been instrumental in promoting the use of specifi c pesticides in agriculture, at the
farm level, through extension services that provide training, demonstrations and consultancy
to farmers.
The livestock industry has been threatened by diseases such as East Coast fever (theileriosis), an
acute cattle disease caused by ticks, and anaplasmosis, an infectious disease in ruminants caused by
blood-sucking insects. The organophosphorus compound chlorfenvinphos has been extensively used
in vector control in livestock (Keating 1983; Kituyi, Wandiga and Jumba 1997; Wandiga, Lalah and
Kaigwara 2002). DDT was mainly used to control the malaria vector (i.e., the Anopheles mosquito),
particularly during outbreak of disease (Mosha and Subra 1982; Wandiga, Lalah and Kaigwara
2002).
In the public health sector, World Health Organisation (WHO) programmes have helped
control vector-borne diseases such as malaria, African sleeping sickness, bilharziasis (transmitted
by parasitic fl ukes of the genus Schistosoma Sambon) and fascioliasis (transmitted by liver fl ukes
of the genus Fasciola L ). Pesticides have been used to control vectors including mosquitoes, tse tse
fl ies and water snails ( Biomphalaria pfeifferi Krauss (Gastropoda: Planorbidae)), respectively, in
the Mwea Tabere settlement scheme, Kano Plain and Lambwe Valley, for example (Wandiga, Lalah
and Kaigwara 2002). In such instances spraying was prescribed by the government-supported pro-
grammes to make these areas habitable for people.
The records in the Ministry of Agriculture library, from the 1980s and 1990s, were quite detailed,
often indicating the types and quantities of pesticides used (refer back to Section 3.2.1). However,
when we paid a visit to the library in 2009, we were unable to fi nd most of the District and Provincial
annual reports for the period from 2000 to 2009. And, when reports were available, the identity
and amount of pesticides used were either completely absent or lacked the meticulous detail of
the reports from prior decades. To us, this served as an indication that current national agricultural
records of agricultural inputs, including the amounts and rates of application of agrochemicals, need
to be more rigorously maintained and brought back to the previous standards. These differences are
indeed evident in Table 3.1.
In the late 1990s, approximately 33% of Kenyan farmers, primarily large-scale farm operators,
used pesticides. Most small farms operated on a subsistence level, with minimal use of pesticides
(Kanja 1988; Wandiga, Lalah and Kaigwara 2002). Current usage patterns have changed since
then, especially in the horticultural industry which has expanded very rapidly. For example, fl ower
exports have increased tremendously as an industry, and about 50% of all UK fl ower imports (espe-
cially roses) now originate from Kenya. Dieldrin, DDT and endosulfan, used to control mosquitoes
and tse tse fl ies, have now been replaced with organophosphorus compounds, carbamates and pyre-
throids. For example, pirimiphos-methyl is used against adult mosquitoes outdoors and permethrin
is sprayed in households to treat bed nets, curtains and fabric against mosquitoes and other biting
insects. Niclosamide and trifenmorph have been used in the Mwea Tabere settlement scheme to
control the water snail. Bromophos, dichlorvos, pirimiphos-methyl and malathion are the main pesti-
cides used to treat stored grain, while a combined permethrin/piperonyl/dichlorvos aerosol formula-
tion is sprayed to control crawling and fl ying insects, cockroaches, ants, housefl ies and mosquitoes
(Wandiga, Lalah and Kaigwara 2002).
By 1997, PCPB had registered 370 formulations (representing 217 active ingredients) for use in
Kenya (Ohayo-Mitoko 1997; Wandiga, Lalah and Kaigwara 2002). Since its inception in the early
1980s, the Board has banned or restricted the use of a number of pesticides, most of them organo-
chlorines (see Table 3.5).
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