Background
Agriculture is the primary production sector that contributes to the Gross Domestic Product (GDP) of Cameroon [
1]. It is also the main source of employment in the country. Maize production is the main source of income for more than three million small-scale farmers in Cameroon. Though the government subsidizes maize production, this support falls far short of farmers’ needs due to the myriads of production constraints including persistent pest problems such as stem borers.
Lepidopterous stem borers seriously limit potentially attainable maize yields by infesting the crop throughout its growth stages from seedling to maturity [
2]. In Cameroon, maize is grown across all agro-ecological zones, from sea level to the highlands at 2000 m a.s.l., and the stem borers are present in all these zones. However, the pest densities and plant damage vary greatly between fields [
3]. The most important species that reduce maize yield in West and Central Africa are the pink stalk borer,
Sesamia calamistis Hampson (Lepidoptera: Noctuidae), the African sugarcane stalk borer,
Eldana saccharina Walker (Lepidoptera: Pyralidae) and the maize stalk borer,
Busseola fusca Fuller (Lepidoptera: Noctuidae) [
4‐
6]. Yield losses of food grain in areas with severe borer problems vary between 10-70 % [
7‐
10]. In most of Cameroon, these stem borers are often controlled using conventional insecticides. However, these Synthetic insecticides are unacceptable since they may lead to problems of toxic residues, health and environmental hazards [
9,
11] when inappropriately used. As stem borers burrow into the stem, they are often protected from contact insecticides [
10]. Various methods of cultural control of stem borers in Africa have been reviewed [
12‐
15], these are most relevant and economical to African resource-poor farmers. Though many of these methods are labor intensive, they have little adverse environmental effects and are readily applicable without extra investment in expensive equipment
In Tanzania farmers have greatly relied on indigenous knowledge and/or plant pesticides to meet their daily needs [
16]. This knowledge is most relevant to the rural poor and marginalized population. Several indigenous plant based pest management options used for the control of field and storage insect pests have been identified by research in parts of Tanazania [
17]. The studies indicated that botanical formulations reduced stem-borer load by more than 55 % and increased maize yield by more than 60 % compared to the control. Over several decades indigenous knowledge practices have been incorporated into scientific knowledge for development and conservation of natural resources [
18]. Hegazy et al. [
19] and Mugisha-Kamatenesi et al. [
20], found that if thoroughly investigated, the current knowledge gained from indigenous plant species may provide more goods and services for local use. In many parts of Africa, derivatives of indigenous plants like
Piper guineense and
Tephrosia vogelii gained attention because of their insect pest control potential [
21,
22]. More so,
Jatropha curcas (native to the American tropics, but widely distributed from Senegal to Cameroon) is also widely used for pest control. Entire or powdered fruits of
Piper spp
. have insecticidal and/or repulsive effects against many pests [
23‐
25].
Despite the enormous potential that has existed for generations, plant based indigenous pest control practices have remained largely unexploited due to limited research intervention and resources committed. However, current interest in reducing environmental contamination and global warming are serving as added impetus for the re-evaluation and intensification of environmentally friendly and cost-effective pest management technologies such as the use of traditional botanical pest control agents [
26]. Many studies carried out in parts of Africa found that plant derived ash including those of wood and cocoa pod increased P, K, Ca, Mg status of soil and pH and yield of vegetables, rice, millet and maize [
27‐
29]. Farmers’ knowledge of various constraints varies qualitatively/quantitatively depending on their interest in the subject, the environment, and its relevance to their lives. Use of indigenous and plant-based insecticides has been greatly neglected in Fako division and this may partly explain why farmers rely solely on synthetic pesticides. In order to improve food security and alleviate poverty in this region, indigenous pest control measures need to be documented and scientifically validated. Their methods of use also need to be standardized in order to popularize these age-old practices.
Therefore, these studies were conducted to investigate farmers’ knowledge and perception on maize stem borers and their indigenous control methods in South Western region of Cameroon. We hypothesized that the farmers: (1) perceived stem borers as important pest of maize; (2) they have their own indigenous methods of control and only (3) use chemical pesticides because they have no alternative, but would prefer plant material if these are standardized since they are safer and cheaper.
We therefore sought to know whether or not farmers in the South West Region of Cameroon know about maize stem borers, if they rate them as important pests of maize and how they combat this problem. Farmers were also asked whether or not they used any indigenous methods and/or plant-based products against stem borers, if they could recognize the plants used and how effective these methods were vis-à-vis chemical/synthetic products as well as whether they will prefer to use indigenous or conventional methods to mitigate their maize pest problems in future?
We also sought to know if there were differences in knowledge and practices in controlling maize pest problems between men and women as well as among the different villages studied.
Materials and methods
Study site
The survey was conducted in the rainforest agroecological zone of Cameroon. A total of 151 farmers from four villages (Maumu and Ekona for Muyuka subdivision and Lower Bokova, and Bonduma for Buea sub division) in the Fako division of the South West Region were interviewed. Farmers were selected on the bases that each has been involved in maize cultivation for at least one year and were willing to participate in the study. The villages used in the study are in Buea (4°08’ 036”N, 9°25’ 826”E; 573 m asl) with rich volcanic rocky soils and temperature ranges of 20-25 °C and Muyuka (4°150’ 45”N, 9°28’ 431”E; 599 m asl) with sandy soil and high temperatures ranges from 20–28.1 °C, an altitude of 378 m sub-divisions. The location of these villages in a predominantly agrarian area and gender heterogeneity of the participants was a strong driving force on the farmers’ perceptions. Buea is more cosmopolitan, with mountainous rich volcanic soils and favorable climatic conditions for maize cultivation. Muyuka, being warmer, favors the rapid buildup of pest populations. The farming community of the Maumu village in Muyuka is inaccessible due to poor road infrastructures and heavy rains, particularly during the rainy season (June to September). The poor roads prevent proper functioning of markets and lack of agricultural inputs. Most of the farmers being females have no direct contact with extension workers. The main food crops in the region are maize Zea mays, cassava Manihot spp, cocoyam Colocasia esculentum, groundnuts Arachis hypogaea, beans Phaseolus vulgaris, banana/plantains Musa spp, with vegetables and few spices as secondary crops while oil palm Elaeis guineensis, cocoa Theobroma cacao and coffee are the main cash crops.
General characteristics of respondents
Generally, small-scale (subsistence) farming (86.09 %) was the primary economic activity of most of the respondents while the remaining, (9.93 %) practiced farming as a part time job. Within the different villages, 100 % of respondents in Maumu; 40.63 % in Bonduma; 97.73 % in Ekona and 97.50 % in Lower Bokova respectively practiced farming as their main occupation. Maize farming experience ranged from 1–50 years. All of the respondent (100 %) grow food crops, 32.45 % of these also grow cash crops, while 13.33 % kept animals in addition. In all, 76.82 % of the respondents grow their maize in mixed cropping system, 17.22 % in mono cropping while 5.96 % practiced both.
Besides the growing of food crops, most of the farmers in Muyuka subdivision also grew cash crops, especially coffee. Most (94.04 %) of the farmers plant maize twice a year, while 2.65 % and 3.31 % respectively grow maize once and three times a year. Most (92.05 %) of the harvested maize is used for household feeding; while 7.95 % is for sale or animal feed. The majority of the respondents (58.94 %) had completed primary education, 16.56 % had no formal education while 24.51 % had secondary and pre-university education. Within the four villages, 28.13 % in Bonduma, 61.36 % in Ekona, 62.50 % in Lower Bokova and 80.00 % in Maumu of the respondents had completed primary education. The study revealed that more farmers in Buea were educated, and involved in business than those in Muyuka. In Muyuka most of the farmers had no formal education; therefore farming was their main source of living (Table
1).
Table 1
Variables showing the significant differences between Muyuka and Buea subdivisions
Buea | 1206 ± 1840.80 | 28 (7) | 88.89 (8) | 40 (52) | 30.6 (15) | 44.4 (4) | 10 (1) | 91.7 (22) | 76.9 (20) | 25 (10) |
Muyuka | 478.99 ± 1040.49 | 72 (18) | 11.11 (1) | 60 (78) | 69.4 (34) | 55.6 (5) | 90 (9) | 8.3 (2) | 23.1 (6) | 75 (30) |
X2value or Z-value* | 3.61* | 4.8 | 5.44 | 5.2 | 7.4 | 0.11 | 6.4 | 16.7 | 7.5 | 10 |
P-value | 0.0003 | 0.03 | 0.02 | 0.022 | 0.007 | 0.008 | 0.01 | 0.0001 | 0.006 | 0.002 |
Survey
A semi-structured questionnaire was used in the survey. A total of 151 farmers (72.85 % females and 27.15 % males) 35 in Maumu, 40 in Lower Bokova, 44 in Ekona and 32 in Bonduma, were interviewed separately within their farming areas or around their residence. Farmers were selected on the bases that each has been involved in maize cultivation for at least one year and were willing to participate in the study. Interviews were done in English or local language (pidgin) with the assistance of local agricultural extension workers.
The questionnaire sought to know: (a) the kind of indigenous methods and plant products used by farmers for maize stem borer control and their main constraints, as well as their knowledge on stem borer problems (b) if they use chemical/synthetic products to control pests, their names, the frequency of use and the constraints linked to their use; (c) whether they had contacts with agricultural extension workers, and their future preference between indigenous and conventional methods in dealing with pests and disease problems in maize fields. Data were also collected on the socio-economic characteristics of respondents.
Statistical analysis
For each variable, statistical comparison between the two sexes, the two locations and four villages were done based on the procedure of the software SAS (‘Statistical Analysis Systems’ version 9.1). The frequencies of respondent were also analysed with Chi-square test using PROC PREQ while the Kruskal-Wallis and Wilcoxon two sample tests using the ‘Nonparametric One Way’ (‘NPAR1WAY WILCOXON’) procedure were used in the absence of normality to compare the means of quantitative variables. All probabilities were appreciated at the 5 % confidence level.
Discussion
Apart from food crops, farmers in Fako division of South West Region of Cameroon also grow cash crops and also rare animals for home consumption. Most of the crops are attacked by field pests during the rainy season when crops are in the vegetative and reproductive stages; this greatly reduces the farmers’ harvests. Most of the pests problems encountered are on cereals, particularly maize. Crop products are stored as food reserves in these areas, while some of the produce are used for income generation. Considering that the maize yields are always low, partly due to pests/diseases and other allied constraints, it has serious implications on their food security needs.
Land, labour, finance, pests and diseases were the most important constraints to maize production in the Fako division of the South West region of Cameroon. As is the case in most parts of Africa [
30], most of the smallholders’ farmers in Cameroon are women with two-thirds of their farms being below 2 hectares. Many practice low-resource agriculture based primarily on the use of local resources with modest external inputs. Increased urbanization causes a shift of farmland into urban areas, thus reducing available space for farming [
31]. The quantity of available land and farm inputs determine maize output. Similar results were obtained by [
32] in the West region of Cameroon, stating that, maize yields were low due to reduced farm sizes, low quality of maize seeds planted, inadequate labour, fertilizer and agrochemicals inputs. Most of the food production burden falls on women and children because of rural urban migration and reduction in active work force wreaked by various diseases and ill-health [
33]. Children are sometimes denied the chance to go to school to assist in weeding because of labour scarcity, resulting in low educational performance [
34]. Pest and diseases were the major constraints limiting attainable maize yields. In the farmers’ perceptions, pest and diseases were amongst the most important constraints in crops in this region. Most of them showed some degree of awareness of the different insect pests that attack their crops. Similar results were reported by [
32] in the forest and humid forest of Cameroon, which corroborates with the findings of [
35]. Increase in pest and disease may partly be as a result of increased use of pesticides by larger corporations which makes the pest become resistant and later shift into the untreated fields.
The study showed that the farmers regarded stem borers as important pests of maize in Fako division of the South West Cameroon. Stem borers interfere with the movement of water and metabolites through the plant’s vascular system, which stunts its growth and development. Attacks during the first eight weeks after sowing result in “dead heart” and late damage (beyond eight weeks after sowing) leads to stem lodging. Both types of damage to the crop cause drastic loss in maize yield [
36]. The farmers reported an increased damage during the dry season when pest populations are higher. Farmers’ perceived that, the insect pests had economic implications, given that the insects caused significant damage that warranted the implementation of control measures. These perceptions contribute to the understanding of various aspects of the bio-ecology of insect pests [
36,
37]. Similar results were also obtained in the humid forest and Western highlands of Cameroon [
38‐
40].
The results indicated that only 45.70 % of the farmers used one indigenous method or another, while 54.30 % depended solely on conventional control methods, which are expensive. Some reported that indigenous methods were time-consuming and they were not sure of the results. Those who used indigenous methods believed they were cheaper and they faced no problems with their use. Cultural/indigenous practices are not expensive for the farmers and do not necessitate in general, supplementary material investments to control insect pests [
41]. A large proportion of the farmers believed indigenous control methods are not effective similar to the findings of [
41], which stated that the development of traditional/indigenous control methods is very limited.
The results showed that very few farmers were using plants as insect pest control methods in their fields. Farmers perceived plant derivatives could not give the desired results achieved when conventional methods are used. Possibly integrating the use of resistant plants with plant derivatives could be a better option for replacing synthetic chemicals, given that they are simple, economical and important strategies in insect pest control. They are also not dangerous to the environment and are generally compatible with other pest control methods [
11,
41]. Farmers’ knowledge and perception of their use can accelerate and facilitate their adoption in the local communities.
More farmers depended on pesticides than on botanical control, although not adequately informed about their proper use similar to studies carried out by the Ministry of Agriculture which showed that more than 42 % of farmers use pesticides [
42]. Increased use of pesticides is due to the proliferation and accessibility of unlicensed dealers’ shops that are only out to make money but care less about the consequences of pesticides. Farmers relied mostly on estimations for the amount and concentration required for a given botanical pesticide formulation because most of them are illiterate. Therefore, there might be risk of overdose, since most of them do not have frequent contacts with extension workers. The most mentioned pesticides used by farmers are Mocap (Ethopropos) and Cypercal. The former, being the cheapest and readily available while the latter, classified as “1b” by the World Health Organization (WHO) and qualified as highly dangerous [
42] is no longer recommended [
43]. Mocap (Ethopropos) is an organophosphate (classified as IA), extremely hazardous to eyes, and the body when inhaled especially as farmers donot use personal protective equipments (PPE) during pesticide applications. Most of these insecticides are also highly dangerous to the environment and pollute water bodies. Substances classified in these category by WHO should not be applied by untrained or inadequately protected people [
44‐
46].
Indigenous control methods were important because most of the farming in these areas are subsistence. Despite the fact that most of the farmers acknowledge the effectiveness of plant-based insecticides, most of them would still prefer conventional products in future if they are affordable. This may be because those who use the indigenous controls and botanicals do not know the right formulations and amounts to apply, as well as the time of application. The main component of this indigenous control was ash from burnt wood collected from local kitchens. Owolabi et al. [
29] studied the effect of liming materials such as plant derived ash on maize yield, and found that it increased soil pH and maize yield.
The findings showed that there was heterogeneity in knowledge between the two locations as well as in gender respectively. In most of the responses, the women seemed to perceive the pest incidences with equal importance. Most of the males interviewed were from Lower Bokova (17), followed by Bonduma (14) which are villages in Buea with a higher level of education. While most of the females were found in Ekona (42) and Maumu (27) and farming was their main occupation without any formal education. This confirms why their perceptions were different, as more women than men reported increased incidence of stem borers in their fields. Perception differences in gender have also been observed in Nepal, where men generally used more vague attributes like harmful or harmless, while women were more specific, regarding the depredatory insects [
37]. Gender differences in perception may also be due to division of labour, as most of the women in this region spend equal time in fields as well as household tasks while the men are involved in farming and community works.
In absence of a standardized protocol on preparation and application, the indigenous plant-based formulations will have varied efficacies at different times even with the same farmer. Without the standardization of the specific amount of a product used, exposure time and way of preparation and no proper application rate and method, efficacy rating of any pesticide will be compromised. There is therefore need to increase productivity through the development of alternative low-cost plant-derived technologies for fighting pests and diseases in crop fields. Studies in China showed that some of these plants, such as the leaves and twigs of
Tephrosia vogelii do possess strong antifeedant stomach poison and growth inhibiting effects against many insect pests, including the stem borers [
47].
Therefore, if the use of ash and other plant derivatives are exploited further and their qualities improved and quantified these will be of great use to the resource-poor farming communities in this region. Most especially if the particular plant is known for its insect control potentials.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
EOO main author, involved in the study design, conducted interviews, literature review and general data collection, wrote the first draft and concluded the final version of this manuscript. NNN main coordinator-supervisor of the research project; contributed with original data and the designing of all the researches; participated in reviewed several drafts of the manuscript. SK has participated in the improvement of the literature review; has done data analysis and interpretation; has corrected the first draft and reviewed several drafts of the manuscript. MNA (Director of ASWA-RUDEP), contributed to introduce the main author to various farmers’ group to conduct interviews with help of extension workers. All authors read and approved the final manuscript.
EOO is Assistant Lecturer (University of Yaoundé 1) and PhD student (University of Buea). NNN Associate Professor (University of Buea). SK Senior Lecturer (University of Yaoundé 1). MNA Executive Director of South West Agriculturist Rural Development Projects (ASWA-RUDEP).