Responding to Economic Crisis in Sub-Saharan Africa: New Farmer-Developed Pest Management Strategies in Cocoa-Based Plantations in Southern Cameroon

Cocoa is a key or source of income and poverty reduction in the humid forest of Southern Cameroon. Cameroon like other African countries went through a major economic crisis in the early 1980s with a decline in international commodity prices and significant changes in macroeconomic policies. Structural adjustment reforms following the economic crisis led to removal of fertilizers and pesticides subsidies, cocoa price liberalization and the overall withdraw of Government interventions from the cocoa sub-sector. Cocoa input price increases have been compounded by the devaluation of the CFA Franc, which doubled the prices of the imported pesticides which were considered key to the control of cocoa pests. This overall economic shock led to changes in cocoa producer's production decisions as a response to minimize cost. Among the changes the use of alternatives to imported chemicals for cocoa pest control. Farmers responded to the high prices of pesticides by developing, from local botanical knowledge and pest management strategies, which include plant extracts and plant extracts mixed with pesticides at different proportions. This is a major decision given the importance of imported chemical in the cost of production of cocoa. Valuable indigenous knowledge from farmers could be used also as an effective support system for communicating and diffusing modern knowledge and technologies to farmers. The paper describes the farmer knowledge-based alternatives to chemical pesticides for pest control in cocoa fields as a response to high pest control costs. Pest management specialists are urged to take advantage of this shift in practice and assess their effectiveness for further use. Two sets of questions are posed: (1) were the conventional insecticides, with all their problems, really necessary? and (2) are the materials derived from locally grown plants effective pest management agents or are they, in some way, placebos?     

Determinants of farmers’ decisions on pesticide use in oriental tobacco: a survey of common practices

Information about pesticide use and perceptions of their risks among farmers is important for identifying problems associated with pest-control decisions and developing appropriate management practices in given crops. In tobacco, a plant sensitive to many pests and diseases, such information is lacking. The patterns of pesticide use in oriental tobacco, as well as the most important factors for farmers’ decisions relating to chemical pest control were studied among randomly selected farmers in northern Greece on the basis of self-reported information acquired through a pre-tested questionnaire. High reliance of farmers on pesticides and field use of all well-known classes of chemical pesticides were reported. While all the active ingredients reported were registered for pest control in tobacco, they differed considerably in terms of toxicity. A normal cropping season received at least 14–16 pesticide applications for soil disinfection, pest control, and weed control. Most farmers stated that they usually spray chemicals on a calendar basis or on the first appearance of a pest. Efficacy on target pests and market price of the pesticide products to be used were the most important criteria for selection of pesticides, i.e. products that are considered to be highly effective and/or that are cheap are more likely to be selected. Better-educated and more experienced farmers were found to pay more attention to environmental safety and pesticide toxicity. Most farmers felt that pesticide use can reduce crop damage by more than 75%, assuring high yields. Main determinants of pesticide use were primarily the fear of severe yield and economic losses and the doubts about the effectiveness and the correct implementation of alternative pest-control methods. Pesticide use could be reduced by exposing farmers to improved pest-control practices such as site-specific integrated pest management.     

Farmer perceptions and pesticide use practices in vegetable production in Ghana

As an initial part of a programme aimed at promoting safe and sound agricultural practices in Ghana, a study was made of farmers' perceptions of pesticides for use and application in vegetable production, using a small survey of 137 farmers who applied pesticides. Field surveys, interviews, questionnaires and analytical games were used to obtain information on the type, scope and extent of use of pesticides, farmers' knowledge of pesticides, and their perceptions about the chemicals' potential for harm. Data from this sample of farmers were used to describe the status of use of pesticides in vegetable cultivation in Ghana. Using chi2 tests, associations between farmers' age and possible pesticide poisoning symptoms, their farm size and method of spraying pesticides, and their perception of pesticide hazard and its perceived effectiveness against pests were also examined. The survey showed that knapsack sprayers were the most widely used type of equipment for spraying pesticides. However, on large-scale vegetable farms of 6-10 acres, motorised sprayers were also used. Various inappropriate practices in the handling and use of pesticides caused possible poisoning symptoms among those farmers who generally did not wear protective clothing. Younger farmers (<45 years of age) were the most vulnerable group, probably because they did more spraying than older farmers (>45 years of age). Farmers did not necessarily associate hazardous pesticides with better pest control. The introduction of well-targeted training programmes for farmers on the need for and safe use of pesticides is advocated.     

Jointness in farmers' decision to apply pesticides in multiple crops and its determinants at the farm level in Bangladesh

Decision about pesticide application for pest control is an issue of major concern, but research on factors affecting decision-making is limited. This study investigates jointness in farmers' decision to apply pesticides in multiple crops and socio-economic determinants of pesticide use across crops using a survey of 2083 farms from 17 districts in Bangladesh applying a multivariate Tobit model. Overall, 75.4% and 12.7% of the farmers applied pesticides in one and two crops, respectively. The decision to apply pesticides in multiple crops was found to be negatively correlated, providing evidence of jointness. Also, individual socio-economic factors exerted variable influences on pesticide use in different crops. Output price significantly increases pesticide use whereas the influence of fertilizer price and labour wage is varied. Educated farmers use significantly more pesticides in rice and oilseed. Marginal and small farmers use significantly less pesticides in wheat/maize and pulse. Policy implications include price policies to reduce fertilizer prices and engaging agricultural extension agencies and non-governmental organizations to disseminate information on specific crop combinations which will synergistically reduce pesticide use.     

Fall armyworm [Spodoptera frugiperda (J.E. Smith)] damage in maize: management options for flood-recession cropping smallholder farmers

Abstract

We determined fall armyworm abundance, infestation and damage on maize in smallholder farmers’ fields in the Zambezi Valley in northern Zimbabwe. Data were collected through field measurements at four sites and interviews with 101 farmers. Fall armyworm abundance ranged from 13.7 to 33.3 larvae per 30 plants, with infestation exceeding 94% and leaf, silk and tassel damage levels ranging between 25 and 50%. Most larvae on maize plants (P?<?0.05) were at instar stages 2 to 3. Estimated grain yield decrease was 58%. Echinochloa colona and Amaranthus spp. were also damaged by fall armyworm. Farmers experimented with 28 combinations of pesticides, ash, and washing powders. Sixty five percent of the farmers used restricted to highly restricted pesticides. High fall armyworm abundance, infestation and maize damage levels suggest that the Zambezi Valley could become a fall armyworm hotspot. Sequential damage of plant parts signified the persistence of this pest in the study area. We recommend large-scale interventions that include chemical and biological control methods as well as destroying ratoon hosts, publishing information about locally available pesticides for the control of fall armyworm, and farmer training on fall armyworm biology and correct use of pesticides.     

Farmers’ attitudes towards pesticide labels: implications for personal and environmental safety

The label of pesticide containers is a major source of information for the use of pesticides, but research on whether farmers use this information is scarce. A survey of small-scale cotton farmers was conducted in the area of Punjab, Pakistan, to study attitudes related with the use of pesticide labels. The majority of the farmers (97%) stated that they were using pesticide products purchased in their original containers and accompanied by written information for use. However, 73% of the farmers reported that they usually do not read this information. Elderly, less educated, and experienced farmers in chemical pest control, but without previous training, were found to be less likely to read the labels. A large part of the farmers (34%) stated that they primarily rely on information of pesticide retailers for pesticide use, while nearly four out of ten said they usually rely on other sources of information or their own experience with pesticides. A sizeable proportion of the farmers (9%) mentioned that there is no need to receive information on such issues. Effective pesticide risk communication conveyed through label information is important so that potential risks from pesticide handling may be mitigated at the point of use.     

Plant Protection and Production in Modern Society1

Many currently existing agricultural production techniques have been developed in total reliance on effective chemical pest control. Today, however, it is becoming clear that chemical pest control has a number of limitations, and its ever increasing costs may well make it a limiting factor in agricultural production. This has already occurred in a number of cotton growing areas. The need for increased world food production will require improved pest control methods. If no special precautions are taken, we will undoubtedly end up in many other crops with a situation similar to that of cotton. In view of the reduced availability of new pesticides, those currently available should be used in the optimal way. At the present time, the integrated pest control approach is the best means of accomplishing this. The introduction of such programs will require official support through legislation or technical assistance. In the future, various new developments in pest control are to be expected. Greater reliance will be placed on the use of computer science. Further effort will be needed in areas such as crop loss assessment, stored product pests, technical assistance to farmers and pesticide selectivity. Closer international collaboration on plant quarantine matters and pesticide registration are essential for the future of pest control.     

An evaluation of smallholder farmers' knowledge,perceptions, choices and gender perspectives in vegetable pests and diseases control practices in the humid tropics of Cameroon

The use of pesticides on vegetables in Sub-Saharan Africa by small-scale farmers dates back to several decades. However, little research has been conducted to capture farmers’ perception on pesticide use on vegetables. This study aims to identify and evaluate farmers’ local knowledge and perception of vegetable pests and diseases and their protection and management practices in humid tropics of Cameroon. Key informant and focus group interviews complemented with quantitative one-on-one structured interviews of 130 farm households and observational assessments were employed. Standard vegetables such as chili pepper are the preferred vegetables in Bafoussam area, whereas traditional vegetables dominate in the Buea and Ebolowa area. Among over 15 vegetables, more than 60% are in the traditional African vegetables category, with insect infestation and fungal infection known to be the most critical biotic production constraints. Successful intensification and diversification of cocoa-based systems with vegetables will require increasing awareness on safer production methods, long-term harmful effects of pesticide misuse, and strengthening the capacity of regulatory agencies responsible for preventing importation of banned pesticides.     

Growing vegetables in developing countries for local urban populations and export markets: problems confronting small-scale producers

Vegetables attract high applications of pesticides, and farmers in developing countries use many acutely toxic insecticides to control pests on these crops. With the liberalisation of agricultural markets in developing countries, the number of small-scale farmers growing vegetables for both domestic and export markets is increasing. Demand for supplies of year-round and exotic fruit and vegetables has grown in industrialised countries, but with rising quality standards and traceability requirements it is difficult for small-scale farmers to benefit from this lucrative non-traditional agricultural export trade. The demand is high for vegetables in the expanding cities in developing countries, and farmers in peri-urban areas, or rural areas with good access to the cities, are in a position to find a growing market for their produce. Poor storage facilities will often mean that farmers are forced to sell at peak times when prices are low. Farmers rarely have access to training in pesticide use, and have only limited or no access to advice on the complicated management of pesticides. The Food and Agriculture Organisation of the UN is concerned about high levels of poor quality and adulterated pesticides on sale in developing countries. Surveys repeatedly show that without training, farmers are unable to make good crop decisions: recognition of pests and their predators is generally low, leading to decisions to spray to kill any insect; knowledge of product selection, application rates and timing is poor; different products are often combined in the belief that the effect will be greater; re-entry periods after spraying and essential harvest intervals are not known; and without knowledge of alternatives, farmers will often assume that the only solution to pest problems is to spray more frequently. From a consumer's point of view, few developing countries are able to monitor pesticide residues, particularly for produce grown for home consumption: most countries do not have laboratories for even simple residue testing. Changes in European Maximum Residue Limits means that export crops will be rejected if they contain residues at the Limit of Detection of pesticides not registered in Europe. Season-long field level training in Integrated Pest Management can help farmers to become better decision-makers, and to greatly reduce pesticide use while reducing risks to their own health and environment, producing safer products for consumers, maintaining yields, and increasing incomes.     

Laboratory and glasshouse screening of pesticides for adverse effects on the parasite Encarsia formosa gahan

Glasshouse screening of ten pesticides and the effect of water damping showed that all of the pesticides, with the possible exceptions of quinomethionate and heptenophos, were suitable for use in integrated control programmes involving Encarsia formosa. About 50 pesticides were screened in the laboratory for residual effects on adult E. formosa. They were grouped according to whether their effects were harmful, moderate or negligible. Acaricides, except quinomethionate, had negligible effects; fungicides generally had negligible effects though a few had moderate effects. Insecticides were equally divided between those which were harmful or moderate in effect. Individual examples are discussed more fully in relation to previous work and their commercial use in integrated control programmes. The two screening methods produced similar results though the laboratory method had the advantage of being much more rapid. Attention is drawn to the need for a simple test to identify pesticides having sublethal effects on natural enemies and for the standardisation of test methods.     

农作物病虫害防治农药速查系统构建与应用

为了让农户能够直观了解及掌握常见病虫害的防治信息,帮助农户通过智能手机在农田、果园和茶园等现场方便快捷地获取作物病虫害图文识别要点与科学防治方法,为农户提供在线植保技术服务,本研究采用RESTful Web 服务架构设计,运用HTML5移动Web开发技术,借助微信平台作为用户访问入口,开发了一款跨平台 (android/iOS) 的农药速查软件系统,实现了农药信息查询、病虫害图谱查询及后台数据管理等功能。通过建立农药与病虫害间的关联关系,实现了从农药名称和病虫害名称两个途径查询农药信息;所构建的数据库涵盖了蔬菜、果树、水稻、茶叶及烟草等共30种福建省常规种植作物上的重要病虫害农药防治技术。初步运用验证结果表明,该系统整体实用性和稳定性较好,适合在农村基层推广应用。基于微信平台的农药速查系统能够满足植保新技术普及和应用的需求,可为农户提供简单便捷、对症下药的在线植保科技服务,对提高用户安全施药和科学防控能力、推进农药的增效减量均具有重要意义。     

韭菜迟眼蕈蚊研究进展

韭菜迟眼蕈蚊是葱韭蒜类蔬菜重要的地下害虫,尤喜食韭菜,其幼虫俗称韭蛆。因该虫发生量大且为害严重,近几年有些菜农大量使用化学农药,造成韭菜农药残留超标,"毒韭菜"事件频发,已引起社会各界的广泛关注。有关韭菜迟眼蕈蚊的研究主要集中在生物学特性和防治方法两方面,如生活习性、发生规律、化学杀虫剂室内毒力测定和田间药效比较、筛选等。有关组织学、解剖学、生理学的研究甚少,而分子生物学方面的研究尚未见报道。本文对韭菜迟眼蕈蚊的研究成果进行了综述,分析了当前防治方法存在的问题,为今后的研究和防治提供新的思路。     

Black pod: diverse pathogens with a global impact on cocoa yield

ABSTRACT Pathogens of the Straminipile genus Phytophthora cause significant disease losses to global cocoa production. P. megakarya causes significant pod rot and losses due to canker in West Africa, whereas P. capsici and P. citrophthora cause pod rots in Central and South America. The global and highly damaging P. palmivora attacks all parts of the cocoa tree at all stages of the growing cycle. This pathogen causes 20 to 30% pod losses through black pod rot, and kills up to 10% of trees annually through stem cankers. P. palmivora has a complex disease cycle involving several sources of primary inoculum and several modes of dissemination of secondary inoculum. This results in explosive epidemics during favorable environmental conditions. The spread of regional pathogens must be prevented by effective quarantine barriers. Resistance to all these Phytophthora species is typically low in commercial cocoa genotypes. Disease losses can be reduced through integrated management practices that include pruning and shade management, leaf mulching, regular and complete harvesting, sanitation and pod case disposal, appropriate fertilizer application and targeted fungicide use. Packaging these options to improve uptake by smallholders presents a major challenge for the industry.     

Integrated weed management (IWM): why are farmers reluctant to adopt non‐chemical alternatives to herbicides?

Implementation of integrated weed management (IWM) has been poor, with little evidence of concomitant reductions in herbicide use. Non‐chemical methods are often adopted as a means of compensating for reduced herbicide efficacy, due to increasing resistance, rather than as alternatives to herbicides. Reluctance to adopt non‐chemical methods is not due to a lack of research or technology but to a lack of farmer motivation and action. Justifiably, herbicides are often seen as the easier option – their convenience outweighs the increased complexity, costs and management time associated with non‐chemical alternatives. Greater use of non‐chemical alternatives to herbicides will only occur if the following seven aspects are addressed: (i) better recognition of the reasons why farmers are reluctant to use non‐chemical alternatives; (ii) encouraging farmers to adopt a longer‐term approach to weed control; (iii) changing farmers' attitudes to pesticides; (iv) paying more attention to the individual farmer's perspective; (v). greater involvement of economists, social scientists and marketing professionals; (vi) re‐evaluating research and extension priorities; and (vii) changing the mindset of funders of research and extension. If ‘persuasion’ fails to deliver greater implementation of IWM, authorities may resort to greater use of financial and other incentives combined with tougher regulations. © 2018 Society of Chemical Industry     

Management of Stored Wheat Insect Pests in the USA

Management of stored-grain insect pests by farmers or elevator managers should be based upon a knowledge of the grain storage environment and the ecology of insect pests. Grain storage facilities and practices, geographical location, government policies, and marketing demands for grain quality are discussed as factors influencing stored-grain insect pest management decisions in the United States. Typical practices include a small number of grain samples designed to provide grain quality information for segregation, blending and marketing. This low sampling rate results in subjective evaluation and inconsistent penalties for insect-related quality factors. Information on the efficacy of insect pest management practices in the United States, mainly for farm-stored wheat, is discussed, and stored-grain integrated pest management (IPM) is compared to field-crop IPM. The transition from traditional stored-grain insect pest control to IPM will require greater emphasis on sampling to estimate insect densities, the development of sound economic thresholds and decision-making strategies, more selective use of pesticides, and greater use of nonchemical methods such as aeration. New developments in insect monitoring, predictive computer models, grain cooling by aeration, biological control, and fumigation are reviewed, their potential for improving insect pest management is discussed, and future research needs are examined.     

Direct and indirect impacts of integrated pest management on pesticide use: a case of rice agriculture in Java, Indonesia

BACKGROUND: Integrated pest management (IPM) technology has been disseminated since 1989 in Indonesia to cut down pesticide use, but the adoption and diffusion of the technology are still debated. This study aims to estimate the models of demand for pesticides and to analyse the impact of IPM technology on pesticide use. Aggregate cross-section time series data from 1990-1998 are used.RESULTS: The results show that IPM technology reduces the use of pesticides by improving the process of rice production, such that pesticides are more efficiently used. In this case, the IPM technology is not a pest control technique.CONCLUSION There is an indication that IPM technology has been adopted by farmers. This is evidence that the IPM programme in Indonesia was successful in this area. Copyright (c) 2008 Society of Chemical Industry.     

Integration of chemical and biological control systems for arthropods: Evaluation in a multitrophic context

The methods used to evaluate and categorise the effects of pesticides on beneficial arthropods are reviewed, including the potential significance of indirect, ‘sub-lethal’ activity and the importance of bioavailability of pesticides under semi-field or field conditions. Interspecific and intraspecific differences in the susceptibility of natural enemies (parasitoids and predators) to pesticides are considered, including the use of resistant strains in Integrated Pest Management (IPM) systems. The potential impact of pesticide resistance in the target pest on its natural enemies is also discussed. The need to assess the influence of the host plant/cultivar on the efficacy of pesticides for use in integrated control programmes (ditrophic effects) and of the possible effects of such chemicals on host plant/cultivar-pest-parasitoid systems (tritrophic effects) are then described with specific reference to the diamondback moth and key endolarval parasitoids. Finally, the potential for manipulation of tritrophic interactions to enhance parasitism by application of low doses of toxicants is demonstrated.     

四种重要实蝇类害虫对福建省造成的经济损失评估

实蝇类害虫是世界性检疫害虫，对福建省农作物造成为害的主要包含橘小实蝇、南亚寡鬃实蝇、瓜实蝇、具条实蝇4种。这4种实蝇类害虫给福建省水果、蔬菜带来较为严重的经济损失，并且由于防治过程中农药的使用，造成生态环境问题。本研究选取实蝇类害虫为害较为严重的福建省主要水果和蔬菜作为研究对象，从直接经济损失、防治费用和间接经济损失3个层面建立评估模型，并对2016年4种实蝇类害虫造成的经济损失进行评估，旨在通过评估经济损失情况，为今后防治政策的制定提供思路。研究结果显示，这4种实蝇类害虫对福建省造成的经济损失约为313.48亿元，其中直接经济损失约为221.74亿元，防治费用约为84.24亿元，间接经济损失约为7.5亿元。最后，本研究提出了重视有害生物灾情评估、完善经济损失评价方法，开展农户专业培训、提升防控技术水平，加强环境规制力度、发展绿色生态农业等政策建议。     

Spatio-temporal dynamics on a plot scale of cocoa black pod rot caused by <Emphasis Type="Italic">Phytophthora megakarya</Emphasis> in Cameroon

Black pod disease is caused by several species of Phytophthora. In Cameroon, the disease is mainly due to Phytophtora megakarya. The pathogen attacks cocoa pods and can lead to almost total production losses in a plot if no control measures are applied. To control the disease, several research programmes are being conducted: breeding for increased resistance, development of several biocontrol or agronomic methods. However, for better use of a specific method it is useful to have a good understanding of several epidemiological processes and more effectively know how the disease is distributed in the field. The purpose of this study was to describe the spatial development of the disease in several cocoa fields in Cameroon. In particular, we determined the spatial relation of the disease using several tools, including geostatistics models and Moran indices. The results indicated that the disease was not randomly distributed, while correlations between neighbouring cocoa trees existed. The relationships were detected up to a distance of between 7 and 9 m, revealing the wide dispersal pattern of the pathogen over short distances. No spatial structure was found in the spread of the disease in the oldest cocoa plantations and the inoculum was dispersed throughout the plot. Disease dispersal over short distances should make it possible to adapt control methods by attempting to confine the first disease foci in young plots. Research should also be undertaken to limit inoculum dispersal.     

Weed control on hard surfaces in The Netherlands

The non-agricultural use of pesticides in The Netherlands declined in the period 1986-2001 from 127000 to 40000 kg AI per annum. However use on pavements rose from 23% to 50% of the total non-agricultural use. To diminish the dependency on herbicides, both preventive and curative non-chemical weed control methods have been examined. In the future both mechanical and thermal methods can be improved. On a flat pavement mechanical methods are preferred because they are more effective. Two approaches are used by municipalities to lower the environmental impact of the use of herbicides on pavements. The first is to phase out the use of chemicals on hard surfaces and the second is the integrated approach in which herbicides are not prohibited, but used only on places and at times when the risk of run-off is below a mutually accepted level. Both approaches can be effective.