Pests and diseases caused by bacteria, nematodes, fungi and viruses cause significant losses to tomato in West Africa. This study, carried-out within the framework of the IPM-CRSP implemented jointly by IITA, IER and Virginia Tech. and State University, assesses farmers’ perceptions on tomato pests and analyzes factors affecting pest management decision-making. Surveys were carried out in three tomato production areas where pests and diseases are major agricultural problems encountered by farmers. Data were collected a sample of from 343 farmers through a set of questionnaires on tomato production systems. Farmer’s decision-making in pest management was modeled using an econometrics Logit probability model. Results show that the main disease reported by most farmers is tomato leaf curl viruses transmitted by whitefly (Bemissia tabaci). The spray of chemicals was not effective on whitefly-transmitted viruses, but the observance of host free period could significantly reduce the population of whiteflies. Key factors affecting farmers’ pest management decision-making are gender; share of tomato income from household income and the level of farm income. Men are more involved in tomato production due to access to pesticide and effective demand for pesticides because of incomes (purchasing power). This paper concludes that tomato production can increase significantly if improved varieties tolerant to whitefly viruses are developed and disseminated, and farmers trained on the appropriate use of chemicals using a participatory approach to raise their level of awareness and information on effective pesticide use and pest-management decision-making.Agricultural and Food Policy, Agricultural Finance, Crop Production/Industries, Demand and Price Analysis, Environmental Economics and Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Relations/Trade, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,

Coulibaly, Ousmane

Norton, Geoff

Nouhoheflin, Theodore

Sissoko, P.

Soumare, S.

English

Research Papers in Economics

AAAE Conference Proceedings (2007) 199-203 
 
Impact Assessment of agricultural research and development to reduce virus problems 
in tomato production in Mali: Farmers perceptions 
Nouhoheflin T.
1, Coulibaly O.
1, Norton G.
2, Soumare S.
3 and Sissoko P.
3 
1IITA, Biological Control Center for Africa, BP 08-0932 Cotonou, Bénin 
2Virginia Polytechnic and State University Blacksburg, VA 24060 (USA) 
3Institut d’Economie Rural (Mali)  
Abstract 
Pests and diseases caused by bacteria, nematodes, fungi and viruses cause significant losses to tomato in West 
Africa. This study, carried-out within the framework of the IPM-CRSP implemented jointly by IITA, IER and 
Virginia Tech. and State University, assesses farmers’ perceptions on tomato pests and analyzes factors affecting 
pest management decision-making. Surveys were carried out in three tomato production areas where pests and 
diseases are major agricultural problems encountered by farmers. Data were collected a sample of from 343 
farmers through a set of questionnaires on tomato production systems. Farmer’s decision-making in pest 
management was modeled using an econometrics Logit probability model. Results show that the main disease 
reported by most farmers is tomato leaf curl viruses transmitted by whitefly (Bemissia tabaci). The spray of 
chemicals was not effective on whitefly-transmitted viruses, but the observance of host free period could 
significantly reduce the population of whiteflies. Key factors affecting farmers’ pest management decision-
making are gender; share of tomato income from household income and the level of farm income. Men are more 
involved in tomato production due to access to pesticide and effective demand for pesticides because of incomes 
(purchasing power). This paper concludes that tomato production can increase significantly if improved varieties 
tolerant to whitefly viruses are developed and disseminated, and farmers trained on the appropriate use of 
chemicals using a participatory approach to raise their level of awareness and information on effective pesticide 
use and pest-management decision-making.  
 
Introduction 
Tomato viruses, diseases, and other pests have become 
a severe constraint to tomato production in West 
Africa, including Mali (Soumaré and al., 2004). 
Gemini viruses in particular have reduced the yield 
and the area under tomato production throughout the 
region in recent years. Viruses and other pest problems 
have resulted in increased use of chemical pesticides 
in attempt to reduce crop losses. Tomato is sensitive to 
pest pressure and is therefore subject to intensive 
application of chemical pesticides including toxic 
ones. Resistance to pests, low awareness about risks 
and availability of cheap but high toxic pesticides have 
increased their misuse and abuse. The misuse of 
pesticides has raised concerns about health hazards 
linked to intoxications resulting in morbidity, deaths 
and environmental pollution (Coulibaly and al., 2006). 
Various alternatives such as improved varieties 
tolerant to insects and diseases; biopesticides, 
botanical extracts have been tested and promoted to 
reduce the misuse and overuse of pesticides in West  
Africa. Viruses however are particularly difficult to 
manage through only chemical use. Efforts have been 
made jointly to solve virus and other pest problems in 
tomato by the Institute of Rural Economy (IER) of 
Mali, Virginia Tech., AVRDC, IITA and Cornell 
University. This effort has involved collaboration 
between IPM-CRSP managed by Virginia Tech. for 
the assessment of potential impacts of solving or 
reducing specific pest management problems on 
tomato in West Africa, and the Agricultural 
Biotechnology Support Program (ABSPII) managed 
by Cornell University for the development of a 
genetically modified tomato to provide resistance to a 
poty virus that may become problem in the future if 
the Gemini virus problem is solved. This paper 
presents the results of a baseline survey carried-out on 
tomato production in Mali, and analysis of the 
economic impacts of research to reduce virus 
problems. More specifically, it assesses farmers’ 
perceptions and knowledge of tomato pests and 
analyzes factors affecting farmers’ pest management 
decision-making Assessment of Agricultural Research and Development to Reduce Virus in Tomato Production  
200  AAAE Ghana Conference 2007 
Data and Methods 
Sampling and survey: Surveys were carried out within 
tomato farmers’ communities in high tomato 
production areas in Mali in 2006. Data were collected 
from tomato producers, scientists and industry experts. 
A sample of 343 vegetable producers was selected 
across 6 districts in the Southern and Central region. 
Vegetable producers were stratified according to 
tomato basic cropping systems and source of water 
supply for watering.  
Theoretical model: Farmer’s decision-making in pest 
management is modeled using an econometric (Logit) 
model. This model is used to identify key factors most 
likely to affect pest management decision-making of 
tomato producers. We assume that pest management 
decision-making is a function of farm household 
  characteristics, management practices and local 
socioeconomics conditions. Mathematically, Logit 
probability is represented by: 
i i Z Z
i
i e e
e Z
+
=
+
Ζ
=
1
1
1
) ( φ (1) 
∞ < Ζ < ∞ − i  Where Zi = ßXi ; ß a vector of 
unknown coefficients; Xi  a vector of factors of the i
th 
farmers. Φ (ßXi) the probability that the i
th factor will 
affect farmer’s pest management decision-making. 
The probability that a given factor affects pest 
management decision-making is the area under the 
standard normal curve between –∞  and ß Xi. The 
larger is the value of ß Xi, the more important is this 
factor affecting farmer’s decision-making. The change 
in Φ (ßXi) relative to the change in Xi is given by: 
j i
ij
i
i ij
i Z f
X
Z
Z X
X
β
δ
δ
δ
δφ
δ
β δφ
) (
) (
=
⎥
⎥
⎦
⎤
⎢
⎢
⎣
⎡
⎥
⎦
⎤
⎢
⎣
⎡
=  (2) 
Where f(Zi) is the value of density function associated 
with each value of the underlying Zi index. Farmers’ 
pest management decision-making is influenced by a 
vector of factors Xi including farmers characteristics, 
management practices and local socioeconomic 
conditions.  
Empirical specification: The empirical specification of 
the model identifies the likely factors affecting tomato 
pest management decision-making in Mali. The 
descriptive statistics on the variables include in the 
empirical model are given in table 1 
Results and discussion 
Farmers’ Socio-demographic profile: Tomato 
producers are young with an average of 42 years and 
one third are women. Only 20% of tomato producers 
attended primary school, 11% completed secondary 
education, and another 17% were schooled in adult 
education. The percentage of illiterate farmers is 22% 
for females and 31% for males. The majority of 
farmers are members of local grassroots organizations 
where information and experience as well as problems 
linked to crop production are shared and discussed. 
They have significant experience in tomato farming 
with an average of 15 years across the sites. 
Household average size is 8 people. Tomato producers 
are closed to the major market and to the main road. 
The distance from tomato producers’ field to the 
nearest market is on average 7 km and 3 km to the 
nearest major road. 
Farmers’ perceptions and knowledge on tomato pests 
The results indicate that farmers were familiar with 
tomato pests and diseases. The most common diseases 
and viruses reported are bacterial wilt, tomato leaf curl 
viruses, and foliar diseases which are reported by 26%, 
25% and 24% of producers respectively. Leaf spots 
(bacterial leaf spot, grey leaf spot and early blight) are 
also mentioned by 13% of farmers. The main problems 
of tomato production reported during dry season are 
tomato leaf curl viruses (TLCV) and bacterial wilt 
(Gilbertson and al., 2006; Nagaraju and al., 2002). 
Farmers assume that TLCV is caused by a high 
temperature, deficiency in water in the field. Only few 
of them were aware that TLCV was transmitted by a 
whitefly vector, Bemisia tabaci. In the rainy season, 
foliar diseases, early blight (Alternaria solani) grey 
leaf spot (Stemphylium solani) and bacterial leaf spot 
(Xanthomonas campestri) are the most common 
diseases reported by tomato producers. The most 
common tomato pests are worms, aphids, white flies 
and viruses reported by 27%, 22% and 18% of farmers 
respectively. Worms, aphids and white fly are believed 
to decrease yield and/or quality of tomato despite the 
use of chemicals, by 15%, 7% and 5% of farmers 
respectively. The increased resistance to chemical 
pesticides seems to be one of the most important 
factors causing the observed trend in pest severity on 
tomato. The effectiveness of chemical pesticides is not 
a factor, as more than three fourths of tomato 
producers mentioned that chemicals used on tomato 
are effective. Less than 10% of tomato producers 
combine the use of chemicals with other non chemical Nouhoheflin, T. et al. 
Advancing Technical Change in Agriculture  201 
methods such the destruction of host plants, the 
observance of host free period, the use of nets to cover 
seedlings in nursery or the use of plant extracts to 
control tomato pests. 
Factors affecting pest management decision-making: 
Using econometrics Logit probability model, four 
factors have significantly affected tomato producers’ 
pest management decision-making. These variables 
include farmer’s gender (“Gender”), the proportion of 
tomato income in the total annual income (“Tomato 
income”) and the proportion of farm income in the 
total annual income (“Farm income”).  “Tomato 
income” and “Farm income” were negatively 
associated with a producer’s decision-making, 
indicating that the tomato producer whose tomato or 
farm income is a smaller proportion of total annual 
income pays attention to pest management decision-
making.  “Gender” coefficient was positively 
associated with decision-making explaining that men 
are more involved in pest management decision-
making than women. The significant of the farm 
structure  “Land Ownership” variable supposes that 
pest management decision-making is also based on the 
farm characteristics. This variable is positively 
associated with farmer’s decision-making indicating 
that he is willing to practice IPM methods to control 
pests on tomato when he had a property right on the 
land. This result is not comparable to that found by 
McNamara and al, 1991, in assessing factors affecting 
peanut producer adoption of IPM in USA. These 
authors found that the adoption decisions are not based 
on structural characteristics of the farm because 
producers follow only a portion of the IPM 
recommendations. 
Conclusion 
Tomato production remains one of the most important 
cash crops in Mali where it is produced both in dry and 
rainy seasons. Insects, diseases caused by bacteria, 
nematodes, fungi, and viruses are the major production 
constraints and caused significant losses on tomato in 
term of yield and quality. Chemical pesticides are the 
common method used by farmers to control pests on 
tomato, but are not effective on whitefly-transmitted 
viruses. An alternative currently developed includes 
observance of a host free period for tomato production. 
The results show that the most likely factors affecting 
pest management decision-making in Mali include 
  producer’s characteristics and farm structure. 
Management practices and institutional factors 
focusing on producer’s capacity building did not 
statistically influence producers’ decision-making. 
Appropriate measures in order to prevent future 
environmental risks should be taken.  
Farmers need to be trained on the appropriate use of 
chemicals using a participatory approach to raise their 
level of awareness on pesticide use and pest-
management decision-making. 
Acknowledgments 
The authors thank all anonymous referee mainly 
scientists from IER, Virginia Tech. and IITA for their 
full involvement. 
This publication is a result of a collaborative research 
support program funded by USAID.   
References 
Coulibaly, O.; A.J. Cherry, T. Nouhoheflin, C. C. 
Aitchedji and R. Al-Hassan. 2006. Vegetable 
producer perception and willingness to pay for 
biopesticides. Journal of Vegetable Science Vol 
12 (3) (2006)  27-42 
Gilbertson R. and Shetty,  R. 2006.  USAID Mali 
Mission Helps Malian Farmers Battle a Deadly 
Tomato Viruses Diseases through the 
Application of Biotechnology Tools. Mission 
report, UC Davis and USAID Mali July 2006 
McNamara, T. K.; E. M. Wetzstein and G. K. Douce. 
1991. Factor affecting peanut producer adoption 
of integrated pest management. Review of 
 Agricultural Economics, Vol. 13, No. 1. (Jan., 1991), 
pp. 129-139  
Nagaraju, N. H. M. Venkatesh, H. Warburton, V. 
Muniyappa, T. C. B. Chancellor, and J. 2002. 
Colvin Farmers' perceptions and practices for 
managing tomato leaf curl virus disease in 
southern India. In International journal of pest 
management, 2002, 48(4) 333-338. 
Soumaré, S. ; K. M. Moore. 2004. Expérience et 
perception des producteurs de tomate : La virose 
de la tomate au Mali. IER-Mali  ; 
OIRED/Virginia Tech, USA. Report, 15p ®  
 Nouhoheflin, T. et al. 
Advancing Technical Change in Agriculture  203 
 
 
Table 1. Names and description of factors in farmers’ choices  
Variables names  Description of the variables 
Dependant variable 
 
 
Y 
Have you, or any member of your family, ever participated in Farmer Field School (FFS) Training for 
IPM?: 1 for Yes and 0 for No 
Explanatory variable 
Household characteristics 
Gender   1 for male; 0 for female 
Age  Farmer’s age  
Education  Farmer’s educational status (0 for No education, 1 for basic education (6 years), 2 for secondary 
education (7-13 years) 
Farm experience  Number of year in tomato production 
Family labor  Number of persons who work in the family 
Tomato farm size  Area cropped for tomato (in ha) 
Vegetable 
consumption 
Proportion of vegetable consumed 
Tomato income  Share of tomato in farmer annual income 
Farm income  Share of farm income in total annual income 
Management practices 
Place of sale  Place of sale of tomato    1 for market, 2 for field/village 
Factors of pesticide 
choice’s 
The most important factors considered in the choice of pesticides (1 = relative advices, 2 = efficacy, 3 = 
Extension agent advice, 4 = Pesticide cost, 5 = pesticide dealer advice/local radio) 
Socioeconomics factors 
Land ownership  Mode of land uses (1 = Inheritance, 2 = Ownership, 3 = Renting) 
Irrigation   Type of water supply use for tomato cropping (1 = Irrigation system, 2 = Recycled cans, 3 = Rain fed) 
Institutional factors 
Extension   Farmers who have been visited by an agricultural extension agent, 1 = farmer has been visited by an 
extension agent, 0 = otherwise 
IPM participation  1 if farmer or any member of his family has participated in Farmer Field School (FFS) training for IPM; 0 
otherwise Assessment of Agricultural Research and Development to Reduce Virus in Tomato Production  
204  AAAE Ghana Conference 2007 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Table 2. Logit regression results for factor affecting pest management decision-making 
 
Explanatory variables   B  S.E.  Wald  df  Sig.  Exp(B) 
Producer characteristics 
Gender  .776  .259 8.990 1  .003 2.172 
Age  -.001 .002 .368  1  .544 .999 
Education  .183  .192 .906  1  .341 1.200 
Farm  experience  .001  .001 1.152 1  .283 1.001 
Family  labor  .004  .005 .761  1  .383 1.004 
Tomato  size  .000  .000 1.404 1  .236 1.000 
Vegetable  consumption  .004  .003 2.433 1  .119 1.004 
Tomato  Income  -.002 .001 4.114 1  .043 .998 
Farm  Income  -.009 .003 5.980 1  .014 .992 
Management practices 
Place of Sale  .001  .001  1.371  1  .242  1.001 
Factors  Pesticides  -.047 .072 .425  1  .514 .954 
Farm structure 
Land  Ownership  .527  .197 7.127 1  .008 1.693 
Irrigation  .001  .001 .740  1  .390 1.001 
Institutional factors 
Extension  .000  .001 .028  1  .866 1.000 
IPM  Participation  .206  .272 .571  1  .450 1.228 
 
Prediction rate = 0.63   X
2 = 77.53   Df = 15    Sig.= .00    -2 Log likelihood = 395.199  

Expérience et perception des producteurs de tomate : La virose de la tomate au Mali. IER-Mali ; OIRED/Virginia Tech,

Farmers' perceptions and practices for managing tomato leaf curl virus disease in southern India.

Vegetable producer perception and willingness to pay for biopesticides.

Impact Assessment of agricultural research and development to reduce virus problems in tomato production in Mali: Farmers perceptions

Impact Assessment of agricultural research and development to reduce virus problems in tomato production in Mali: Farmers perceptions

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