Population genetic structure and phylogeographical pattern of rice grasshopper, Oxya hyla intricata, across Southeast Asia.

The rice grasshopper, Oxya hyla intricata, is a rice pest in Southeast Asia. In this study, population genetic diversity and structure of this Oxya species was examined using both DNA sequences and AFLP technology. The samples of 12 populations were collected from four Southeast Asian countries, among which 175 individuals were analysed using mitochondrial DNA cytochrome c oxidase subunit I (COI) sequences, and 232 individuals were examined using amplified fragment length polymorphisms (AFLP) to test whether the phylogeographical pattern and population genetics of this species are related to past geological events and/or climatic oscillations. No obvious trend of genetic diversity was found along a latitude/longitude gradient among different geographical groups. Phylogenetic analysis indicated three deep monophyletic clades that approximately correspond to three geographical regions separated by high mountains and a deep strait, and TCS analysis also revealed three disconnected networks, suggesting that spatial and temporal separations by vicariance, which were also supported by AMOVA as a source of the molecular variance presented among groups. Gene flow analysis showed that there had been frequent historical gene flow among local populations in different regions, but the networks exhibited no shared haplotype among populations. In conclusion, the past geological events and climatic fluctuations are the most important factor on the phylogeographical structure and genetic patterns of O. hyla intricata in Southeast Asia. Habitat, vegetation, and anthropogenic effect may also contribute to gene flow and introgression of this species. Moreover, temperature, abundant rainfall and a diversity of graminaceous species are beneficial for the migration of O. hyla intricata. High haplotype diversity, deep phylogenetic division, negative Fu's F (s) values and unimodal and multimodal distribution shapes all suggest a complicated demographic expansion pattern of these O. hyla intricata populations, which might have been caused by climatic oscillations during glacial periods in the Quaternary.

Significance of the tropical fire ant Solenopsis geminata (hymenoptera: formicidae) as part of the natural enemy complex responsible for successful biological control of many tropical irrigated rice pests.

The tropical fire ant Solenopsis geminata (Fabricius) often nests very abundantly in the earthen banks (bunds) around irrigated rice fields in the tropics. Where some farmers habitually drain fields to the mud for about 3-4 days, the ants can quickly spread up to about 20 m into the fields where they collect food, including pest prey such as the eggs and young of the apple snail Pomacea caniculata (Lamarck) and insects such as lepidopterous larvae and hoppers, notably Nilaparvata lugens (Stäl) the brown planthopper (Bph) and green leafhoppers Nephotettix spp. Even in drained fields, the activity of S. geminata is restricted by rainfall in the wet season. The relatively few ant workers that forage characteristically into drained fields and on to the transplanted clumps of rice plants (hills) kill the normally few immigrant Bph adults but are initially slower acting than other species of the natural enemy complex. However, larger populations of Bph are fiercely attacked and effectively controlled by rapidly recruited ant workers; whereas, in the absence of the ant, the other natural enemies are inadequate. In normal circumstances, there is no ant recruitment in response to initially small populations of immigrant Bph and no evidence of incompatibility between ant foragers and other natural enemies such as spiders. However, when many ants are quickly and aggressively recruited to attack large populations of Bph, they temporarily displace some spiders from infested hills. It is concluded that, in suitable weather conditions and even when insecticides kill natural enemies within the rice field, periodic drainage that enables S. geminata to join the predator complex is valuable for ant-based control of pests such as snails and Lepidoptera, and especially against relatively large populations of Bph. Drainage practices to benefit ants are fully compatible with recent research, which shows that periodic drainage combats problems of 'yield decline' in intensively irrigated tropical rice and is also needed in South East Asia to make better use of seriously declining water supplies for irrigation.

Brazil and the development of international scientific biosafety testing guidelines for transgenic crops.

Under the umbrella of the International Organisation of Biological Control (IOBC), an international working group of public sector scientists entitled on "Transgenic Organisms in Integrated Pest Management and Biological Control" has been organized. The group will develop scientific principles and detailed scientific guidelines for biosafety testing of transgenic crops. The key elements of this project are: (1) An international initiative including expert scientists from leading research institutions in developed and developing countries; (2) coordination of the development and implementation of the guidelines as a dynamic process, which will include scientific and technical capacity building and communication among scientists and between scientists and policy makers; (3) rapid serial publication of sections of the guidelines as they are completed; and (4) rapid and timely revision of previously published sections. The guidelines will be constructed on a case-by-case basis and will have no regulatory legitimacy themselves.

The role of ants, especially the fire ant, Solenopsis geminata (Hymenoptera: Formicidae), in the biological control of tropical upland rice pests.

Predatory ants are omnipresent year-round in upland (dryland) rice fields in the Philippines. At least 14 species were identified of which the very aggressive Solenopsis geminata (Fabricius) and also Tapinoma sp. nr indicum Forel usually predominated. Some highly aggressive species, notably Pheidolegetonspp. and Bothriomyrmex dalyi Forel were localized. Solenopsis geminata flourished within many fields, not only during the crop season but also throughout dry season fallows where they remained aggressively predatory. Rice plants infested with brown planthopper Nilaparvata lugens (Stål) were usually found within a few hours and S. geminata workers were quickly recruited to N. lugens aggregates. Predation was usually incomplete and workers began to solicit the few remaining late instar or adult N. lugens survivors. These oviposited but no second generation nymphs appeared. There was a surge of recruited ants at the time of N. lugens egg hatch when surviving adults were also killed. Initially, S. geminataalone killed N. lugens aggregates less quickly than with the whole predator complex but ultimately its sole effect was as great as that of the complex. Scattered N. lugens adults, corresponding to numbers that initially colonize rice plants, were eliminated as quickly by S. geminata alone as by the predator complex. Tapinoma indicum occurring separately or with S. geminataon the same plant contributed to predation of N. lugens especially on young nymphs. Solenopsis geminataattacked other insects on rice notably leaffolders of which 97% mortality was recorded when they were exposed throughout egg and larval stages. The role of S. geminataas a predator of upland rice pests is discussed in the context of known biological control of pests of non-rice dryland crops in the tropics and sub-tropics by S. geminata and other Solenopsis spp.

Communication and implementation of change in crop protection.

The slow adoption of integrated pest management (IPM) has been attributed to the widespread gaps in farmers' knowledge of rational pest management. Other factors such as farmers' perception of high input use and promotion of pesticides also influence decisions to practise rational pest management. To bridge these gaps and improve farmers' pest management practices, most IPM implementation programmes rely on communication strategies. These communication approaches utilize either mass media or interpersonal channels or a combination. The choice of which communication approach to employ depends on project objectives and resources. Among extension and communication approaches used in crop protection, strategic extension campaigns, farmer field schools and farmer participatory research stand out in their ability to bring about significant changes in farmers' pest management practices. While extension campaigns have greater reach, farmer participation and experiential learning achieve more impact because learning effects are sustained. Communication media are important in raising awareness and creating a demand for IPM information but interpersonal channels and group methods such as the farmer field school and farmer participatory research are essential to accomplish the tasks of discovery and experiential learning of IPM skills.