Interest in trap cropping, a traditional tool of pest management, has increased considerably in recent years. In this review we propose a broader definition of trap cropping that encompasses the inherent characteristics of the trap crop plants themselves as well as the strategies associated with their deployment. Inherent characteristics of a trap crop may include not only natural differential attractiveness for oviposition and feeding, but also other attributes that enable the trap crop plants to serve as a sink for insects or the pathogens they vector. Successful deployment of trap crops within a landscape depends on the inherent characteristics of the trap crop and the higher value crop, the spatial and temporal characteristics of each, the behavior and movement patterns of insect pests, and the agronomic and economic requirements of the production system. Thus, trap cropping is more knowledge-intensive than many other forms of pest management. We review recent references on trap cropping, classify them according to their modalities and level of implementation, and provide a synthesis of the factors that influence the success of trap cropping. Last, we provide a list of recommendations and guidelines that should prove helpful in moving trap cropping forward to its full potential.

Concepts and applications of trap cropping in pest management

Advances in cowpea research , Advances in cowpea research , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Advances in cowpea research

Summary
1. Vector-borne pathogens and parasites can induce changes in the phenotypes of their hosts that influence the frequency and nature of host–vector interactions and hence transmission, as documented by both empirical and theoretical studies. To the extent that implications for transmission play a significant role in shaping the evolution of parasite effects on host phenotypes, we may hypothesize that parasites exhibiting similar transmission mechanisms – and thus profiting from similar patterns of interaction among hosts and vectors – will have correspondingly similar effects on relevant host traits. Here, we explore this hypothesis through a survey and synthesis of literature on interactions among plant viruses, their hosts, and insect vectors.

2. Insect-vectored plant viruses that differ in their modes of transmission benefit from different patterns of interaction among host plants and vectors. The transmission of persistently transmitted (PT) viruses requires that vectors feed on an infected host for a sustained period to acquire and circulate (and sometimes replicate) virions, then disperse to a new, healthy host. In contrast, non-persistently transmitted (NPT) viruses are effectively transmitted when vectors briefly probe infected hosts, acquiring virions, then rapidly disperse.

3. Based on these observations, and empirical evidence from our previous work, we hypothesized that PT and NPT viruses will exhibit different effects on aspects of host phenotypes that mediate vector attraction to, arrestment on and dispersal from infected plants. Specifically, we predicted that both PT and NPT viruses would tend to enhance vector attraction to infected hosts, but that they would have contrasting effects on vector settling and feeding preferences and on vector performance, with PT viruses tending to improve host quality for vectors and promote long-term feeding and NPT viruses tending to reduce plant quality and promote rapid dispersal.

4. We evaluated these hypotheses through an analysis of existing literature and found patterns broadly consistent with our expectations. This literature synthesis, together with evidence from other disease systems, suggests that transmission mechanisms may indeed be an important factor influencing the manipulative strategies of vector-borne pathogens, with significant implications for managing viral diseases in agriculture and understanding their impacts on natural plant communities.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2435.2012.02026.x

Transmission mechanisms shape pathogen effects on host-vector interactions: Evidence from plant viruses

▪ Abstract In this article we consider the role of epidemiological factors and transmission processes of insect-vectored viruses on the effectiveness of insecticides in a disease management program. We also discuss the use of insecticides within the broader framework of the chemical environment surrounding vectors, and how chemical-induced alterations in the behavior of vectors can influence transmission. Our analysis confirms the belief of Heathcote, who stated in 1973, that “no one method of control is likely to keep crops entirely free from virus infection and as many preventative measures should be taken as are economically justified.”

Management of plant viral diseases through chemical control of insect vectors.

Pigeonpea (Cajanus cajan) is an important crop in semi-arid tropical and subtropical farming systems, providing high quality vegetable protein, animal feed, and firewood. Insect pests feeding on flowers, pods, and seeds are the most important biotic constraint affecting pigeonpea yields. This review summarizes the biology and ecology of the three most important groups of pests: flower- and pod-feeding Lepidoptera, pod-sucking Hemiptera, and seed-feeding Diptera and Hymenoptera. Recent research investigating the complex interactions among pigeonpea, its key pests, and their natural enemies is also reviewed. These relationships have implications on the pest status of individual species and on possible control strategies. Pigeonpea pest management research has focused until recently on the identification and development of resistant cultivars and on chemical control. Future research must focus on environmentally sound pest management strategies that are compatible with the needs and limitations of pigeonpea farmers. Several priority areas for research are suggested.

/pdf/insect-pests-of-pigeonpea-and-their-management-30bww2xvln.pdf

Insect pests of pigeonpea and their management.

Screening techniques for host plant resistance to cowpea insect pests

The legume pod-borer, Maruca testulalis, continues to be a major limitation to successful cowpea cultivation in many countries. During the past decade, research on this insect has increased in scope and intensity at international agricultural research centres and a number of universities. The work that has been done on the biology and control of this pest at the International Institute of Tropical Agriculture (IITA) is briefly discussed with emphasis on the development of a management strategy centred around host plant resistance, and some suggestions for future research direction are given.

The Legume Pod-Borer, Maruca Testulalis (Geyer): Past, Present and Future Research

Insect pests are major constraints in cowpea production. Breeding for insect resistance is a major objective of cowpea improvement programme at IITA. Resistance to leafhoppers and aphids has been incorporated in advanced breeding lines thus eliminating the need for other control measures. Similarly, a moderate level of resistance to thrips and cowpea storage weevil has also been incorporated thus reducing the damage due to these two pests. A moderate level of resistance to legume pod-borer and pod sucking bugs has also been identified and is being incorporated in advanced breeding lines. The long term strategy is to develop cowpea cultivars with multiple resistance to insect and diseases with superior agronomic characters and local adaptability.

Host Plant Resistance for Cowpea Insect Pest Management

Summary

The effectiveness of the synthetic pyrethroids deltamethrin and lambda-cyhal-othrin in preventing (i) aphid colonisation of four cowpea cultivars with different levels of aphid resistance and (ii) the introduction and subsequent spread of cowpea aphid-borne mosaic virus and cucumber mosaic virus was investigated under tropical field conditions.



Sprays of these pyrethroids eight days apart prevent aphid colonisation and within crop spread of virus by the colonising Aphis craccivora. However, neither deltamethrin nor lambda-cyhalothrin prevented the initial introduction of virus into the cowpea crop and, when incoming alate incidence was high, virus incidence was higher in the sprayed than in the unsprayed plots. In addition, the degree of aphid resistance of each cultivar affected secondary virus spread within the crop, with greatest spread in the most resistant cultivar.

Interaction between two synthetic pyrethroids and the spread of two non-persistent viruses in cowpea

Control of cowpea insect pests has been almost entirely achieved through the use of chemicals by progressive farmers. However, the peasant farmer has traditionally tended to rely on chance and has often been unable to obtain yields that would be profitable. This paper examines the farmer’s dilemma and the jrossibility of using host plant resistance (HPR) as an adjunct to other control methods in developing a sound integrated pest management of cowpea pests. The status of HPR in cowpea is reviewed with a view to identifying the areas where progress has been made with respect to the measurement and identification of resistance to formulate an effective integrated pest control program. The difficulties in achieving this are discussed in the light of our present data bank and the diversity of cowpea pests.

S. R. Singh

Papers

Screening techniques for host plant resistance to cowpea insect pests

The Legume Pod-Borer, Maruca Testulalis (Geyer): Past, Present and Future Research

Host Plant Resistance for Cowpea Insect Pest Management

Interaction between two synthetic pyrethroids and the spread of two non-persistent viruses in cowpea

Varietal Resistance in the Integrated Pest Management of Cowpea Pests