Methods for detecting and for monitoring Prostephanus truncatus (Horn) are crucial components in phyto- sanitary control, research programmes and pest management against this beetle. P. truncatus is unusual in that its populations are distributed widely between natural habitats and stores holding maize grain and dried cassava roots, which necessitates a similarly wide range of sampling methodologies. This review considers successful and unsuccessful approaches to sampling the pest populations in both stores and the natural environment and concludes with a consideration of how monitoring could contribute to integrated pest management for P. truncatus .
The Ecological Areawide Management (TEAM) Leafy Spurge project is a United States Department of Agriculture and Agricultural Research Service (USDA–ARS) regional, Integrated Pest Management (IPM) program focused on the Little Missouri River drainage in the states of North and South Dakota, Montana, and Wyoming, U.S.A. TEAM Leafy Spurge project represents the first large-scale, systematic study and demonstration of weed management alternatives under USDA–ARS's Areawide Pest Management Program. The other three projects previously approved under the program targeted insect pests. TEAM Leafy Spurge's primary goal has been to demonstrate the use of ecologically based IPM strategies to achieve effective, affordable leafy spurge control. TEAM Leafy Spurge is co-chaired and overseen by the USDA–ARS in cooperation with the USDA–Animal and Plant Health Inspection Service. Both agencies have many years of experience in research and implementation of leafy spurge control tactics as well as valuable contacts and resources. Together those federal partners make a powerful team to address the leafy spurge problem on a multi-state basis. Additional federal agencies participating in TEAM Leafy Spurge include: Bureau of Land Management, U.S. Forest Service, National Park Service, Bureau of Indian Affairs, Bureau of Reclamation, and U.S. Geological Service. State partners include: state departments of agriculture and other state agencies, Cooperative Extension Services, land grant universities, and county weed managers, while private sector representatives include landowners and ranchers. A non-partisan ad hoc committee consisting of state and federal researchers, land managers, representatives from local, state, and federal entities, and private landowners/ranchers provides guidance and helps to ensure the quality and applicability of the program. The extensive partnerships are of particular importance because they help to ensure continued dissemination of information past the limited life span of TEAM Leafy Spurge, which is set to expire in 2003. The five components of TEAM Leafy Spurge research and demonstration project are: (1) Program management; (2) Operations; (3) Assessment; (4) Supporting research, and (5) Technology transfer. As of this writing, the bulk of the research work has been completed and now TEAM Leafy Spurge is focusing its energies on assessment and technology transfer projects. Where available, brief outlines of research results are included here in addition to discussion of the program's key components, overall structure and general operation.
The story of Prostephanus truncatus in Africa is described from its original outbreak in Tanzania in the late 1970s to the present day. Information is given on the differing control methods put in place by infested countries and how co-ordination of local programmes and inputs from technical assistance agencies was approached by an agencies. The influence of changes in development thinking on the management of storage pests is considered. The current status of P. truncatus is addressed, inlcuding its impact on the international maize trade, particularly that provided for famine relief. The introduction of Teretrius nigrescens as a biological control agent is described. We also provide some milestones in efforts to manage the pest, describe the effectiveness of pest management in terms of cost benefit and suggest some new avenues that may lead to a sustainable reductioning in P. truncatus in Africa.
Based on current agroecological theory and IPM practices, this review explores the role of traditional practices, involving site selection, soil management, timing of planting and harvesting, crop resistance, intercropping, weed management, harvest residue management, post-harvest management, natural enemies management, mechanical control, repellents and traps in the natural regulation of potential pests. In synthesis, the literature suggests that although pest management professionals focus their efforts on pest control, the preventative approach taken by traditional farmers is more effective. Potential constraints to the implementation of this preventive pest management approach include:(1) lack of integration of ecological theory and pest management, (2) lack of cooperation among social and biological scientists, and (3) lack of real efforts to work with farmers as equals and support mechanisms that protect their knowledge.
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?
In this article, we review studies of the ecology of the larger grain borer, Protephanus truncatus , both outside and within the maize storage systems. Laboratory studies have shown that P. truncatus can breed on a wide range of woody substrates (branches, roots, and seeds). Pheromone trap catches in different habitats strongly suggest that P. truncatus is well-established in certain non-agricultural environments, presumably breeding in dead or dying wood. In Meso-America, West and East Africa, P. truncatus reproduction in the field has been documented in branches ring-barked by cerambycid beetles. Within a maize store, P. truncatus densities can increase from very small initial colonies of probably less than 200 individuals to densities in excess of 1000 beetles per kg after about 4–6 months of storage. Insect parasitoids are very often found in smallholders' grain stores attacked by P. truncatus , but they do not contribute significantly to population regulation. Declines in maize store population levels in Benin from 1993 to 1996, and in adult abundance in pheromone traps in the natural environment in Kenya, have been attributed to predation by the introduced predator, Teretrius nigrescens , but in recent years pheromone trap catches in West Africa suggest that the situation may be complex. Several environmental factors, notably temperature, humidity, and daylength, and their interactions, have been correlated with P. truncatus flight activity, as well as, in West Africa, the emptying of maize stores. Laboratory experiments have shown food quality also affects flight activity. Factors terminating dispersal and flight are most likely attraction to the male-released aggregation pheromone. Short range attraction to plant volatiles has also been recorded. In Africa the highest densities of P. truncatus tend to occur in humid lowlands, which contrasts with the situation in meso-America where P. truncatus tend to occur in greatest numbers in cooler upland regions. Pheromone trap catches can be significant predictors of the risk of stores becoming infested. Coupled with the development of a rule-based model of flight activity, these studies may offer the prospect of predicting the risk of store infestation based upon temperature and humidity measurements.
Leaf eating insect outbreaks of unprecedented severity occurred on oil palms and cocoa in what became Malaysia, from the late 1950s to early 1960s. Growers faced two crucial questions, what to do about the attacks, and what caused them. The tropical climate generally continues suitable for phytophagous insects to realise their large increase capacity, a factor emphasised in the stable agroecosystem of perennial tree crops. Parasitic and predatory natural enemy insects are equally favoured and maintain control. It became increasingly evident that the prime cause of outbreak was disruption of this balance by the introduction of broad spectrum, long residual contact insecticides (bslrcs), with various contributory factors. Patchy pesticide residues would continue to eliminate inherently exploratory parasitic and predatory insects, something worsened by uneven initial application. In these conditions, there is a complete overlap of generations of both pests and enemies, with no evolution of synchronised or otherwise coordinated life cycles (‘continuous generation mode’– CGM). In outbreaks the pests tend to be at a similar lifecycle stage (‘discrete generation mode’– DGM), so that at times a high proportion of an enemy population that may be building up cannot find a suitable host stage. Simply stopping application was often enough to end the vicious circle of treatment and reoutbreak, but also, commonly, there was heavy damage in the meantime. Selective application was developed, involving inherent pesticide characteristics or method of use opposite in at least one aspect to bslrc (i.e. narrow spectrum, short residue life, or non-contact). Large areas were treated, e.g., from the air. Infestations mostly disappeared with only one or a few applications. In that era of the 1960s, chemical application compatible with biological control was known as ‘integrated control’. The bslrcs had been introduced to control other regularly occurring pests (‘key’ pests), limited localised build up of the target pests e.g., from climatic fluctuations (‘occasional’ pest), or as a ‘precaution’. Some species only appeared after disruption started (‘potential’ pest). Development of selective chemical control continued to be for key and occasional pests, aiming at effective kill once decided upon. Census monitoring ensured application only when justified economically, with timing to the most vulnerable stage in the pest lifecycle. Among non-chemical approaches, cultural methods include provision of suitable flora in the ground vegetation for food sources for adult parasitic insects. Reasonably dense ground vegetation cover is grown to suppress rhinoceros beetle damage in oil palm replantings. Other possibilities include dissemination of insect diseases, traps and attractants, and resistant plant types. This fitted ‘pest management’ which by the mid-1970s came to encompass selective chemical use, as ‘integrated pest management (IPM)’. There were similar developments in other parts of the world, and in other perennial tree crops, extended also to short term crops (e.g., rice and vegetables). IPM is not an esoteric methodology awaiting ‘complete knowledge’. It can be applied on the basis of principle and existing knowledge for the most reliable economic control, targetted to encompass any aspect, such as toxicology and environmental effects.
Wildlife is often responsible for causing extensive damage to personal property, human health and safety concerns, and other nuisance problems because of their feeding, roosting, breeding, and loafing habits. Frightening devices are tools used in integrated wildlife damage management to reduce the impacts of animals, but the effectiveness of such devices is often variable. An animal's visual and auditory capabilities affect how the animal will respond to a stimulus. Frightening devices include pyrotechnics, gas exploders, effigies, lights, lasers, reflective objects, guard animals, bioacoustics, and ultrasonic devices. We examined scientific literature on the use of frightening devices to reduce bird and mammal depredation and compiled results to determine the effectiveness of such devices. When used in an integrated system, frightening devices may be more effective than when used alone. We conclude that the total elimination of damage may be impossible, but frightening devices and/or combinations of devices are useful in reducing wildlife damage. Ultrasonic frightening devices are ineffective in repelling birds and mammals whereas other devices offer some protection. The timely use of a variety of frightening devices can be part of a cost-effective integrated system to reduce wildlife damage to tolerable levels.
Many threatened and endangered species are negatively impacted by predation. Management of the predators that are geographically and temporally in position to threaten species of concern can greatly aid in their conservation. However, decisions on management strategies are based within economic constraints, while the success of management actions is measured by wildlife resource improvement. Here, we review methods for applying monetary valuations for threatened and endangered species so that economic analyses of management actions can be used to help guide and evaluate management decisions. A variety of applied examples are provided to demonstrate the principles.
The markets for organic produce offer the opportunity for smallholders in Africa (and elsewhere) to increase their income through access to the price premiums paid in Europe and North America. Facing declining soil fertility, the high cost of off-farm inputs and the collapse of state or para-statal input credit schemes, organic farming offers a sustainable solution for resource-poor farming communities, quite apart from the lure of price premiums. The use of purchased inputs is already at a low level in the smallholder sector in Africa and this may allow farm produce to immediately meet organic standards. The principles of IPM can be applied to organic agriculture to achieve adequate pest and disease control with the restricted use of pesticides that is required for farm produce to meet organic standards. The paper describes some of the problems facing smallholders wishing to access organic markets and describes the IPM options available, which meet the standards of organic certification.
This paper describes the evolution of IPM in Cuba during three pre- and post-revolutionary periods. The state of the art of IPM after the collapse of Cuba's relations with the soviet block is analyzed in detail. During this 'special period' Cuba is undergoing a major conversion from conventional agriculture dependent on external inputs to a semi-organic agriculture dependent on local resources and low external inputs. The massive production and use of microbial pesticides complemented by cultural and habitat management techniques are at the heart of this new quest of agricultural sustainability in the midst of the economic crisis. About 982,000 ha of various crops are under biological control, with savings of about US$ 30 million in pesticide imports.
A description of the bostrichid beetle Prostephanus truncatus is given, with a history of name changes and systematic position since its first description in 1878. Common names and guides to identification keys of larvae, pupae and adults are also provided.
After about 25 years of intensive research a substantial moment of information has accumulated on the basic biology of Prostephanus truncatus in stored products. This article reviews the literature on the geographical distribution, biotypes, symbiotic associations, mating and flight behaviour, oviposition, and development on both agricultural and non-agricultural hosts. The current knowledge about the nutritional biology (including the role of symbionts) and host finding behaviour (including the inter-linked roles of plant chemicals and the insect's own pheronones) are highlighted as research areas which deserve future attention. In addition, few studies have been conducted to determine the extent to which the biology of P. truncatus permits it to survive and reproduce in non-agricultural environments. These areas of study should be pursued as possible routes to providing more effective integrated pest managements strategies for the larger grain borer.
An overview of information on damage caused by the larger grain borer is provided, including details of early studies examining commodities that might be attacked and the importance of LGB field infestations in relation to storage losses. In addition, examples are given from published information on the weight losses that can result from LGB infestation in maize and cassava, with case studies. Problems in applying conventional methods of loss assessment to commodities attacked by LGB are highlighted, to suggest the need to develop alternative techniques. Experiences in developing and applying novel approaches to loss assessment for LGB are reported. Examples are also given to show how loss and damage estimates have been used to describe the impact of the pest on farmers, and on local, regional and international grain trading.
Imports of pesticides have long been subsidised for use in the cocoa agroforests of the humid forest zone of southern Cameroon. With the liberalisation of the cocoa and pesticides sectors and the devaluation of the local currency (CFA franc), farmers are facing fluctuations in the price paid for cocoa and the high cost of farm inputs. Without the support of the extension services, they themselves have developed traditional integrated control methods based on the use of plant extracts mixed with conventional pesticides. From a survey of 300 cocoa farmers, the study assesses the farmers' command of these methods, the pests controlled, the problems encountered and the institutional constraints in the definition and dissemination of integrated control methods. The study concludes with recommendations for research and development towards the better definition and dissemination of integrated control methods.
The establishment of P. truncatus in Africa has highlighted the inherent weakness of phytosanitary measures against exotic pests. Consideration is given to the need for phytosanitary measures and how patterns of international trade affect phytosanitary control. To prevent the spread of pests such as P. truncatus , large grain shipments can be subject to stringent pest control procedures. However, a significant proportion of grain movement in Africa, both within countries and across borders, occurs informally by both illicit, commercial movement of multiple truckloads of grain and legally by individuals carrying headloads via bush paths or small parcels on public transport. Attempts to locate and inspect the small lots would be impractical. Some recommendations are given on how the spread of P. truncatus in large-scale international trade can be slowed but otherwise it is accepted that in the long-term the prevention of further spread of P. truncatus in Africa is wholly unrealistic.
Since its introduction into Africa 25 years ago, approaches to the management of the larger grain borer at farm level have gone through many changes. This article reviews the literature on chemical and non-chemical protection of maize and cassava after harvest from the perspective of the small-scale farmer during this period. The influence of traditional store design on Prostephanus truncatus and the history of changes in the use of post-harvest chemicals are described. Synthetic and non-synthetic chemicals, host plant resistance, store design, fumigation, plant products, inert dusts and thermal disinfestation all have a role to play. Attention is also given to the ways in which farmers in sub-Saharan Africa coped with the introduction of and damage caused by Prostephanus truncatus. Given the expense, poor distribution and health concerns of the use of synthetic chemicals, emphasis should be placed on the integration of low cost and low impact methods that could provide adequate control of this important post-harvest pest.
