Tim Chancellor

Obstacles to integrated pest management adoption in developing countries

Significance Integrated pest management (IPM) has been the dominant crop protection paradigm promoted globally since the 1960s. However, its adoption by developing country farmers is surprisingly low. This article reports 51 potential reasons why, identified and prioritized by hundreds of IPM professionals and practitioners around the world. Stakeholders from developing countries prioritized different adoption obstacles than those from high-income countries. Surprisingly, a few of the obstacles prioritized in developing countries appear to be overlooked by the literature. We suggest that a more vigorous analysis and discussion of the factors discouraging IPM adoption in developing countries may accelerate the progress needed to bring about its full potential. Despite its theoretical prominence and sound principles, integrated pest management (IPM) continues to suffer from anemic adoption rates in developing countries. To shed light on the reasons, we surveyed the opinions of a large and diverse pool of IPM professionals and practitioners from 96 countries by using structured concept mapping. The first phase of this method elicited 413 open-ended responses on perceived obstacles to IPM. Analysis of responses revealed 51 unique statements on obstacles, the most frequent of which was “insufficient training and technical support to farmers.” Cluster analyses, based on participant opinions, grouped these unique statements into six themes: research weaknesses, outreach weaknesses, IPM weaknesses, farmer weaknesses, pesticide industry interference, and weak adoption incentives. Subsequently, 163 participants rated the obstacles expressed in the 51 unique statements according to importance and remediation difficulty. Respondents from developing countries and high-income countries rated the obstacles differently. As a group, developing-country respondents rated “IPM requires collective action within a farming community” as their top obstacle to IPM adoption. Respondents from high-income countries prioritized instead the “shortage of well-qualified IPM experts and extensionists.” Differential prioritization was also evident among developing-country regions, and when obstacle statements were grouped into themes. Results highlighted the need to improve the participation of stakeholders from developing countries in the IPM adoption debate, and also to situate the debate within specific regional contexts.

Risk assessment for rice planthopper and tungro disease outbreaks

Abstract Comparisons are drawn between the decision-making processes used in the management of two major pests of Asian rice production, namely, the brown planthopper (BPH) Nilaparvata lugens , and rice tungro virus disease (RTVD), which is transmitted primarily by green leafhoppers, Nephotettix spp. BPH exhibits quite different population dynamics and behaviour in the tropical and the temperate parts of its range, and this has important implications for its management. In the tropics, BPH is usually regarded as a secondary pest which becomes a problem only due to misuse of insecticides. Thus the risk of inadvertently inducing resurgence by the planthopper must be considered when attempting to control other rice pests. In temperate rice systems, the number of immigrants entering the crop and the temperature during the growing season are the main driving variables determining BPH population size. Here decisions can be made both in response to early warnings of planthopper immigration and in response to monitoring of populations during the cropping period. With RTVD (which occurs only in tropical systems), measures to prevent plant-to-plant spread of the disease within a crop are relatively ineffective. Early warning of the risk of tungro infection, however, would allow preventive measures to be taken such as the adjustment of planting times or the targeted deployment of resistant varieties.

Development of silverleaf assay, protein and nucleic acid-based diagnostic techniques for the quick and reliable detection and monitoring of biotype B of the whitefly, Bemisia tabaci (Gennadius).

The aim of this study was to develop and optimize silverleaf bioassay, esterase analysis and PCR-based techniques to distinguish quickly and reliably biotype B of the whitefly, Bemisia tabaci (Gennadius), from Indian indigenous biotypes. Zucchini and squash readily develop silverleaf symptoms upon feeding by the B biotype, but they are not readily available in Indian markets. A local pumpkin variety Big was, therefore, used in silverleaf assay, which developed symptoms similar to those on zucchini and squash and can be used reliably to detect B biotype. Analysis of non-specific esterases of B and the indigenous biotypes indicated both quantitative and qualitative differences in esterase patterns. Two high molecular weight bands were unique to B biotype and they occurred in abundance. These esterases were used to develop quick and field-based novel detection methods for differentiating B from the indigenous biotypes. Development of these simple and cost-effective protocols has wider application as they can be potentially used to identify other agricultural pests. Mitochondrial cytochrome oxidase I gene sequences and randomly amplified polymorphic DNA (RAPD) polymorphisms, generated using the primer OpB11, were also found useful for detecting B. tabaci biotypes. A B biotype-specific RAPD band of 800 bp was sequenced, which was used to a develop sequence characterized amplified region (SCAR) marker. The SCAR marker involved the development of B biotype-specific primers that amplified 550 bp PCR products only from B biotype genomic DNA. Silverleaf assay, esterases, RAPDs or a SCAR marker were used in combination to analyse whitefly samples collected from selected locations in India, and it was found that any of these techniques can be used singly or in combination to detect B biotype reliably. The B biotype was found in southern parts of India but not in the north in 2004-06.

The flight activity and infectivity of the major leafhopper vectors (Hemiptera: Cicadellidae) of rice tungro viruses in an irrigated rice area in the Philippines

The flight activity of each of the three major leafhopper vectors of rice tungro viruses, Nephotettix virescens (Distant), N. nigropictus (Stal) and Recilia dorsalis (Motschulsky) was closely associated with rice cropping periods and was influenced by crop growth stage and season. Leafhopper flight was influenced by changing levels of illumination at dusk and dawn and, for R. dorsalis only, was significantly affected by moon phase. Recilia dorsalis was the dominant species caught in suction traps at 0.75 m and 1.5 m and an upwardly-directed light trap at 4.0 m, whereas N. virescens was the most abundant species caught on sticky yellow traps at the height of the canopy. Infectivity tests on migrant leafhoppers caught in upwardly-directed light traps showed that N. virescens was the most common transmitter of rice tungro viruses. Infective leafhoppers were recorded at the end of dry seasons and during wet seasons in 1991 and 1992. The risk of tungro disease incidence was very low early in the 1991 dry season, when aerial abundance of leafhoppers was small and no infective individuals were recorded.

Insect‐screened cultivation to reduce the invasion of tomato crops by Bemisia tabaci: modelling the impact on virus disease and vector

1u2002In two experiments carried out in Guadeloupe, barriers were used to reduce the entry of the virus vector Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) to tomato plots. The barriers erected around the crop were of insect‐proof cloth fences (<50u2003mesh), 1.5u2003m in height, in the first experiment with a deltamethrin‐treated, insect‐attracting strip facing inwards, and, in the second, with the barrier but no insecticide‐treated strip.

Spread of Plant Virus Disease to New Plantings: A Case Study of Rice Tungro Disease

The spread of plant virus disease between fields is reviewed for several horticultural and agricultural crops. Previous studies have focused on cropping systems where there is scope for using separation in time and space to reduce the potential for virus spread between plantings. In our study, data are presented on virus disease spread between fields in an irrigated rice area in the tropics where crops are grown continuously throughout the year. An intensive survey was conducted in rice fields planted from November 1992 to October 1994 in which the occurrence of new infections of rice tungro virus disease was recorded. The effect of a number of variables on disease incidence, including the proximity of a field to inoculum sources, was examined using ordinal regression analysis. Primary infection showed large seasonal fluctuation. In addition, the number of leafhopper vectors had a significant effect, as did the tungro vector resistance of the rice variety grown. The distance to nearest inoculum source and the tungro incidence of this source significantly affected the level of infection occurring in a vulnerable field. The results are discussed in relation to management strategies to reduce the spread of tungro disease between fields in irrigated lowland rice cropping systems.

Larval performance and adult attraction of Delia platura (Diptera: Anthomyiidae) in a native and an introduced crop

Abstract Delia platura Meigen is an important pest in crops around the world. Its host range includes almost 50 species, and it can develop in soil organic matter. In Ecuador, D. platura is a serious problem for the crop, Lupinus mutabilis Sweet (Chocho), and it also attacks broccoli (Brassica oleracea L.). After broccoli is harvested, crop residue is mixed with soil or collected and stored close to Chocho fields. The objectives of this study were to determine the adaptive responses of larvae reared on different hosts and whether D. platura females are preferentially attracted to germinating L. mutabilis seeds or broccoli residue. Accordingly, larval performance and attraction of female D. platura reared on broccoli residue and L. mutabilis seeds were evaluated. The number of larvae, pupae, and adults were higher when reared on broccoli. Conversely, pupal weight was higher and time from larva to pupa, pupa to adult, and total life cycle were longer in flies reared on L. mutabilis. Although D. platura developed more quickly on broccoli, L. mutabilis was also a good host since pupae were heavier compared with flies reared on broccoli. Delia platura females reared on broccoli preferred broccoli residue to L. mutabilis in an olfactometer. Volatiles from broccoli residue in soil may attract D. platura females and stimulate oviposition on L. mutabilis seeds. Environmentally benign production of L. mutabilis crops with minimal insecticide applications may require the elimination of fresh broccoli residue as fertilizer in soils where L. mutabilis is cultivated.

Stimulating private investment in agricultural research for greater impact on poverty reduction

This article reviews the international experience with approaches to encouraging private investment in agricultural research and technology for a greater impact on poverty reduction. Some specific types of technologies and the roles for public and private sector involvement in generating new technology are identified, as well as the potential for public–private partnerships. Three most promising mechanisms for stimulating private investment in agricultural research are then revised in some detail: taxation schemes, co-funding arrangements, and output-based approaches. The article concludes that in order to help create a significant impact on poverty reduction, the innovative incentive system of tying rewards to adoption of technology development is the most likely to succeed.

How can the poor benefit from private investment in agricultural research? A case study from Bolivia

This article evaluates potential mechanisms for facilitating increased private-sector engagement in agricultural research for development and technology transfer (ARDTT), with particular emphasis on Bolivia. It reviews the mixed results of efforts, in developed and developing countries alike, to decentralise ARDTT and to encourage private-sector investment. Potential mechanisms for Bolivia are considered within three broad categories: taxation schemes; co-funding arrangements; and output-based approaches. The constraints to participation in ARDTT by the private sector that arise from concerns over high transaction costs, intellectual property rights, and the legal and regulatory environment are also assessed. The article concludes that compliance, or a hybrid of compliance and a competitive co-funding scheme, is most suited to Bolivias needs. A flexible approach to intellectual property rights systems is required, although it remains a challenge to identify appropriate taxation regimes.