Geoff Norton

Mechanisms of compensation of rice plants to yellow stem borer Scirpophaga incertulas (Walker) injury

Abstract Field and greenhouse experiments were conducted to investigate the impact of stem borer injury on the physiology and yield response of irrigated rice. The compensation mechanisms investigated included increased tillering, increased percentage of productive tillers, and increased grain weight. Assimilates were translocated from stem borer-injured tillers to healthy tillers. The photosynthesis rate of green leaves in stem borer-injured tillers increased. The results indicate that all these mechanisms can be employed by rice plants in response to stem borer injury. The implications for rice pest management, including breeding for cultivars tolerant to stem borer injury, nitrogen fertilisation to encourage plant compensation, and an increase in the economic threshold for stem borers, are discussed.

Facilitating IPM: The role of participatory workshops

Successful, long-term implementation of Integrated Pest Management (IPM) requires the integration of key technical and management activities and the participation of a wide range of stakeholders including farmers, researchers, extension officers, crop consultants, government agencies, and industry. A key issue that needs urgent attention is how to achieve the high quality interaction between these different groups which is necessary for sustained IPM. Problem specification and planning workshops (PSPWs) provide one means of facilitating an integrated strategy for tackling complex pest management issues. Since 1992, the Cooperative Research Centre for Tropical Pest Management has facilitated over 20 PSPWs, focusing on different farming systems in Australia. This paper describes the philosophy, the process involved, and the impact that these PSPWs have had. It examines three specific cases to describe the relationship between plans and results and ways of improving impact. The results reinforce the major role that social scientists can play in providing mechanisms for collaborating with technical researchers and other partners to facilitate effective, participatory ventures in IPM.

Farmers' perceptions of the white stem borer Scirpophaga innotata (Walker), in Cilamaya, West Java, Indonesia

Abstract In connection with the white stem borer outbreak, reported during the 1989–1990 wet season in the northern part of West Java, field surveys were conducted to determine the importance of this pest to farmers, to assess their knowledge of it and to determine current control practices. The largest percentage (85%) of farmers perceived the white stem borer as important and difficult to control (22%). When farmers observe white stem borers in their fields most believe that moths migrated from other rice fields. Many farmers were uncertain that an outbreak will occur the next season, mainly because of the lack of understanding of the population dynamics of the pest and the factors causing white stem borer outbreaks. The majority of the farmers use insecticides against white stem borers including those banned by the government with the implementation of the IPM policy in 1986. An account of farmers reliance on pesticide use against white stem borers is discussed.

White stem borer damage and grain yield in irrigated rice in West Java, Indonesia

Factors influencing the relationship between whiteheads caused by the white stem borer Scirpophaga innotata (Walker) and grain yield were investigated. We determined the effect of different numbers of whiteheads on grain yield using different cultivars, nitrogen application, and at different field locations in Cilamaya, West Java. At the same number of panicles and whiteheads per plant, yield reduction is greater in cisadane than in IR64. With increasing nitrogen application, the range in panicle height increased. Except for Ketan, more whiteheads were recorded in shorter panicles. Two locations planted to the same cultivar showed different relationships between whiteheads and grain yield. The relationship between whiteheads and grain yield depends on the distribution of whiteheads in the field. Unless these factors have been taken into consideration, it may be difficult to make a damage prediction of white stem borer in the field

Future Planthopper Management: Increasing the Resilience of Rice Systems

The problem of planthoppers in rice—the causes of planthopper outbreaks and the ways of reducing the likelihood of this happening—is determined by the dynamic interaction between features of the natural system and decisions made in the human use system. A model of the resilience of the rice planthopper system is used to provide a conceptual framework to explore this complex relationship, involving features at different scales, including the crop, farm, village, country and international level. The way in which various combinations of these various factors can determine the resilience landscape and whether a particular rice planthopper system is more or less resilient are discussed; that is, whether planthopper populations remain at low levels or whether rice crops are subject to frequent planthopper outbreaks. Historically, in a number of countries, a breakdown in resilience and the occurrence of planthopper outbreaks have resulted from intensive rice production associated with the increasing use of pesticides and fertilisers, as well as susceptible high-yielding varieties. In the final section, the threat to the resilience of the rice planthopper system resulting from further rice crop intensification to feed the increasing world population is discussed. A number of recommendations are proposed on how this threat might be avoided, including the use of more sustainable practices as part of a second green revolution, such as maintaining and enhancing ecosystem services through better management practices, including more selective use of pesticides and ecological engineering. An important challenge is how to coordinate the decisions made by various stakeholders in achieving a harmonised and resilient approach to rice planthopper management in the future.

Digital Identification Tools in Regulatory Science and Practice

Correct identification of potentially invasive organisms detected at the border, or which have already been introduced into a country, is critical to any biosecurity strategy. Taxonomic specialists have traditionally provided identification services. Unfortunately, taxonomy is a discipline in rapid decline globally, and taxonomists are often unavailable for routine identification. Molecular technology offers an alternative diagnostic tool, but currently is not generally available for the wide range of organisms that must be identified. Moreover, molecular diagnostics probably will not replace traditional identification techniques needed for rapid and confirmatory visual identification procedures. This chapter shows how the development of new software programmes and web technology provides a readily available and practical solution to the problem of achieving rapid and accurate identification of invasive pests intercepted by regulatory programmes. The current use of digital interactive keys and image databases indicate they have considerable potential to train and support biosecurity agency surveillance teams and situations in which the identification of invasive species is important. This chapter provides background information on the traditional, “dichotomous” key system and then describes the essential features of online dichotomous keys, matrix keys and image databases. Examples are provided on the way in which these tools are currently being used. The chapter concludes with a description of remote microscope diagnostics. Together with other developments (collaborative key development projects, cybertaxonomy, increased linkages between digital keys and image databases, and mobile phone technology) remote microscopy is likely to influence the future of digital identification aids.