**4. Beyond pesticide application**

Resistance in pests due to chemical application is one of the major factors disrupting traditional pest management practices in West Africa. In order to maximize rice production and agricultural intensification while minimizing reliance on expensive pesticides, a longterm pest management strategies including varietal resistance, biological control and improved cultural practices is needed. IPM seeks to integrate multidisciplinary approach (combination of options) with limited pesticide use to provide effective environmentally sound, socially acceptable and economically safe solution to pest problems. AfricaRice and partners have developed some chemical free products for smallholder farmers in West Africa. Specific examples are provided below:

#### **4.1 Varietal resistance**

Improving varietal resistance or tolerance to insect pests is one of the most promising options for managing insect pests in West Africa. AfricaRice and partners have identified several Oyrza sativa varieties with resistance/tolerance to the AfRGM. Cisadane (from Indonesia) has been selected as a variety tolerant to AfRGM and released in Nigeria as FARO 51 based on initial selection at NCRI and on-farm studies in Abakaliki by AfricaRice. BW 348-1 (from Sri Lanka) has good tolerance to AfRGM *and* iron toxicity under field conditions. It has been released in Burkina Faso and Mali (WARDA, 2003). Leizhung (from South Korea) is another tolerant variety to AfRGM released in Mali. Suitable lowland NERICAs being screened for insect resistance or tolerance include: NERICA L-25 and NERICA L-49 (Nwilene *et al.,* unpubl. data). AfricaRice identified one tropical *O. sativa* variety (TOS 14519 from The Gambia) with moderate resistance to AfRGM, which is currently used as a resistant check variety in screening. Several traditional *Oryza glaberrimas*  (e.g. TOG 7106 – from Mali, TOG 7206 – from Côte d'Ivoire, TOG 7442 – from Nigeria and TOG 6346 – from Liberia) have been found to be highly resistant to the pest (Nwilene *et al.,*  2002).

#### **4.2 Biological control**

316 Pesticides in the Modern World - Risks and Benefits

whose impact may endure for decades and adversely affect soil conservation (USEPA, 2007). Pesticide related poisoning deaths are often caused by using pesticide packages or containers after they are emptied of toxicants. It was reported by Youm *et al.* (1990) that forty six residents in Ilorin area of Nigeria were hospitalized as a result of "mistakenly drinking or eating pesticides". Also, in a study conducted by Hotton *et al.* (2010) in the northeastern part of Nigeria on effect of pesticide use, he found out various ailments associated with pesticide use and the use of pesticide container. These include: bronchilis chest pain, asthma, cough, running nose, vomiting, nausea, excessive sweating, diarrhea, burning on urination, abdominal pain, irritation of eye, temporarily and permanent lost of vision, weakness of arms, hands and legs, stiffeners of the waist, fatigue, etc. Empty pesticide containers are used to store food because of a lack of understanding on dangers of pesticides, poor pesticide labeling, and a low literacy rate. Pesticides that are applied to crops can volatilize and may be blown by winds into nearby areas, potentially posing a threat to wildlife (Sequoia & Kings, 2007). More importantly, the remains of these pesticides flow back to the streams and river. Some people at the other end will fetch it for drinking and for other domestic activities thus resulting to one ailment or the other depending on the concentration. Fish and other aquatic biota may be harmed by pesticide-contaminated water

Resistance in pests due to chemical application is one of the major factors disrupting traditional pest management practices in West Africa. In order to maximize rice production and agricultural intensification while minimizing reliance on expensive pesticides, a longterm pest management strategies including varietal resistance, biological control and improved cultural practices is needed. IPM seeks to integrate multidisciplinary approach (combination of options) with limited pesticide use to provide effective environmentally sound, socially acceptable and economically safe solution to pest problems. AfricaRice and partners have developed some chemical free products for smallholder farmers in West

Improving varietal resistance or tolerance to insect pests is one of the most promising options for managing insect pests in West Africa. AfricaRice and partners have identified several Oyrza sativa varieties with resistance/tolerance to the AfRGM. Cisadane (from Indonesia) has been selected as a variety tolerant to AfRGM and released in Nigeria as FARO 51 based on initial selection at NCRI and on-farm studies in Abakaliki by AfricaRice. BW 348-1 (from Sri Lanka) has good tolerance to AfRGM *and* iron toxicity under field conditions. It has been released in Burkina Faso and Mali (WARDA, 2003). Leizhung (from South Korea) is another tolerant variety to AfRGM released in Mali. Suitable lowland NERICAs being screened for insect resistance or tolerance include: NERICA L-25 and NERICA L-49 (Nwilene *et al.,* unpubl. data). AfricaRice identified one tropical *O. sativa* variety (TOS 14519 from The Gambia) with moderate resistance to AfRGM, which is currently used as a resistant check variety in screening. Several traditional *Oryza glaberrimas*  (e.g. TOG 7106 – from Mali, TOG 7206 – from Côte d'Ivoire, TOG 7442 – from Nigeria and TOG 6346 – from Liberia) have been found to be highly resistant to the pest (Nwilene *et al.,* 

(Collin *et al.,* 2008).

**4.1 Varietal resistance** 

2002).

**4. Beyond pesticide application** 

Africa. Specific examples are provided below:

Biological control is a major component of sustainable agricultural systems that are designed and managed to reduce dependence on chemical and other energy-based inputs, minimize ecological risk resulting from farming practices, and enhance agricultural productivity in relation to resources available. To ensure that biological control will contribute to sustainable agriculture, AfricaRice identified the gregarious endoparasitoid *Platygaster diplosisae* (Hymenoptera: Platygastridae) and the solitary ectoparasitoid *Aprostocetus procerae* (Hymenoptera: Eulophidae) are the most important wasps attacking AfRGM. The *Paspalum* gall midge (PGM) *Orseolia bonzii* Harris (Diptera: Cecidomyiidae) which infests *Paspalum scrobiculatum* L. (Poaceae), a common weed in rice agroecosystems, is distinct from AfRGM, and is an alternative host for the two main parasitoids of AfRGM. The delay between the destruction of *Paspalum scrobiculatum* and the appearance of AfRGM populations on a rice crop means that the large majority of the parasitoids from *O. bonzii* die before AfRGM population is available – asynchrony between pest and associated natural enemies. AfricaRice has shown that habitat manipulation with *Paspalum scrobiculatum*  management at the edge of rice fields had significantly increased the carry-over of parasitoids from *Paspalum* gall midge (*Orseolia bonzii*) to AfRGM. The combination of beneficial organisms, tolerant varieties and habitat management suppressed AfRGM, restored nature's balance, and resulted in increased rice yields (Nwilene et al., 2008a).

#### **4.3 Chemical-free products**

Chemical free products for insect pest control include the use of botanicals and biological control using pathogens. AfricaRice has demonstrated that neem seed powder and neem oil can provide effective control against termites in West Africa (Nwilene et al., 2008b). Termites constitute a major biotic constraint to upland rice production in West Africa. The control of termites has largely relied on broad spectrum and persistent organochlorine insecticides. Land use practices can affect the flow of water and persistent pesticides along toposequences from the fragile upland to the lowlands thereby causing harmful effect to humans. To meet the needs of upland rice farmers in West Africa, AfricaRice has shown that the biological control pathogen – the entomopathogenic fungus *Metarhizium anisopliae* is effective against termites on rice fields and can also be used as alternative to persistent chemical pesticides because of the serious health and environmental risks in terms of pollution, destruction/death of non-target/useful insects, and the reduction of biodiversity.

#### **4.4 Adoption of IPM practices**

The Food and Agriculture Organization of the United Nations in collaboration with technical assistance from AfricaRice introduced the concept of IPM training in farmer field school (FFS) to West Africa through a series of technical cooperation projects in irrigated rice schemes in Ghana, Cote d'Ivoire and Burkina Faso. Following the success of this programme, IPM farmer field school projects were extended to several other countries in West, Eastern and Southern Africa. The initial results obtained by farmers who applied IPM practices for irrigated rice production in Ghana showed that yields of rice were consistently higher in IPM fields than in fields where conventional farming practices were adopted. In the rice fields where farmers adopted IPM practices, pesticide use for pest control was reduced by over 90% and savings on pesticide use amounted to \$100 per ha. Net returns from such fields were 32% higher than in farmer practice fields. Data from Mali show

Is Pesticide Use Sustainable in Lowland Rice Intensification in West Africa? 319

Collin, A. E., T. H. Suchanek, A. E. Colwell, N. L. Anderson and P. B. Moyle. 2008. Changes

Ephraim, N., J. Pender, E. Kato, O. Omobowale, D. Phillip, S. Ehui 2010. Nigeria Strategy Support Program. International Food Policy Research Institute (IFPRI) 9. pp1-4. Hotton A.J, J.T. Barminas, S.A Osemeahon, T. Aboki. 2010. Monitoring of cholinesterase

Nacro S. 2000. La formation participative en gestion intégrée des déprédateurs des cultures

Nelson M. and J. Mohamed-Katerere 2006. Africa environment outlook: our environment,

Nguu V. N. 2008. Sustainable intensification of rice production for food security in the near

NISER (Nigerian Institute of Social Economic Research). 2005. An Overview of the Nigerian

Nwilene, F.E., C.T. Williams, M.N. Ukwungwu, D. Dakouo, S. Nacro, A. Hamadoun, S.I.

Nwilene F. E., K.F. Nwanze and O. Okhidievbie. 2006. African rice gall midge: biology,

Nwilene, F.E., A.Togola, T.A. Agunbiade, O.E. Ogah, M.N. Ukwungwu, A. Hamadoun, S.I.

Nwilene, F.E., T.A Agunbiade, A. Togola, O. Youm, O. Ajayi, S.O. Oikeh, S. Ofodile and O.

Owusu, M. E. 1971. Bathycoe!ia tlwlassino, another serious pest of cocoa in Ghana. Coconut

PAN (Pesticide Action Network). 2010. Understanding the full costs of pesticides:

Sakurai T. 2006. Intensification of rainfed lowland rice production in West Africa: present status and potential green revolution. The Developing Economies 44(2): 232–251. Sosan, M.B., E.A. Amos, A.O. Isaac and A. D. Muheez. 2008. Insecticide residues in the

Marketing Board Newsletter (Accra, Ghana) 467: 12-14.

Journal of Chemosphere 72: 781 – 784.

planktivorous fish. Ecological Applications 18(8): 213-226.

Journal of Scientific Research 46(1): 028-035. ISBN:1450-216X.

Sahéliennes No. 4/5: 74–80.

Ibadan – Nigeria No. 32. pp. 9.

Pest Management 48(3), 195–201.

(AfricaRice), Cotonou. 20 pp.

14.

1081.

28(1), 37–44.

UK No 2: 26-27.

our wealth chemicals. UNEP 2: 250-374.

in fish diets and food web mercury bioaccumulation induced by an invasive

inhibition among retailers of agrochemicals in Northeastern Nigeria. European

à travers les champs-écoles des producteurs au Mali. Etudes et Recherches

future – A summary report by the secretary, International Rice Commission. Pp 1-

Rice Economy: The Nigerian Institute of Social and Economic Research (NISER),

Kamara, O. Okhidievbie, F.J. Abamu and A. Adam 2002. Reactions of differential rice genotypes to African rice gall midge in West Africa. International Journal of

ecology and control. Field Guide and Technical Manual. Africa Rice Center

Kamara, and D. Dakouo 2008a. Parasitoid biodiversity conservation for sustainable management of the African rice gall midge, *Orseolia oryzivora* (Diptera: Cecidomyiidae) in lowland rice. Biocontrol Science and Technology 18(10), 1075–

O. Falola 2008b. Efficacy of traditional practices and botanicals for the control of termites on rice at Ikenne, Nigeria. International Journal of Tropical Insect Science

Experience from the Field, with a Focus on Africa. Pesticide Action Network (PAN)

blood serum and domestic water source Cacao farmers in Southwestern Nigeria.

conclusively that by adopting IPM practices farmers are able to increase the production of rice by 9 - 21%, increase revenue by 14% to 35% while at the same time significantly reducing pesticide use by up to 100% (Nacro, 2000; Youdeowei, 2001 and 2004).
