Roger Day

Variations in Leptocybe invasa (Hymenoptera: Eulophidae) population intensity and infestation on eucalyptus germplasms in Uganda and Kenya

Leptocybe invasa, an invasive gall-inducing wasp of Australian origin, recently emerged as a serious eucalyptus pest of global importance. We examined the spatial and temporal variations in L. invasa adult populations and evaluated eucalyptus gemplasms for infestations by the wasp in Uganda and Kenya. There were significant differences in L. invasa abundance, gall incidence, severity and damage index between sites. Adults occurred throughout the year, indicating overlapping generations since the adults are known to live <7 d. There was no obvious peak in L. invasa population abundance although a general decline was observed in dry months. Out of 35 eucalyptus germplasms evaluated for L. invasa infestations, only Eucalyptus henryi and the clonal hybrids GC 578 and GC581 were resistant to the pest. Most germplasms were ranked as tolerant or moderately susceptible to wasp attack. Highly susceptible germplasms included Eucalyptus camaldulensis, GC540 and GC784 in Tororo, Uganda, and MAU1, GC14, GC15 and GC10 in Busia, Kenya. Implications of the year-round occurence of L. invasa adult populations and gall infestations, and the potential for host resistance in managing the pest, are discussed.

Farmers' knowledge, perceptions and management of the gall-forming wasp, Leptocybe invasa (Hymenoptera: Eulophidae), on Eucalyptus species in Uganda

Abstract Farmers growing Eucalyptus species in Uganda were interviewed using a pre-tested questionnaire to investigate their knowledge, perceptions and management of the Eucalyptus gall-forming wasp, Leptocybe invasa Fisher & LaSalle, with the aim of developing integrated management programme for the pest. Farmers were aware of, and concerned about, the gall problem on Eucalyptus, but the vast majority of them did not know the cause. Most farmers did not attempt to control the infestation because they did not know of suitable control methods and/or the cause of the problem. Farmers control decisions were not influenced by their experience in cultivating Eucalyptus or their education level. Only 20% of 59 farmers interviewed had received advice on L. invasa, suggesting poor flow of information on tree pests to farmers. Nearly all farmers interviewed still wanted to plant Eucalyptus, and they saw the trees as a source of several products and services. Problems relating to the increasing emergence of alien insect pests in tropical forests, and challenges and strategies for effective management of forest pests in developing countries are discussed.

The impacts of some classical biological control successes.

We differentiate between the success of a classical biological control programme and its impact; the former addressing the completed implementation of the steps of a biological control programme, and the anticipated reduction of the target pest, and the latter addressing the societal and environmental benefits of control of the target pest. We provide ten case studies in which CABI has played a role to illustrate aspects of success and impact for biological control programmes against insects pests and weeds: cassava mealybug (Phenacoccus manihoti), mango mealybug (Rastrococcus invadens), pink hibiscus mealybug (Maconellicoccus hirsutus), orthezia bug (Insignorthezia insignis), brown peach aphid (Pterochloroides persicae), banana skipper (Erionota torus), black sage (Varronia curassavica), rubber vine (Cryptostegia grandiflora), leafy spurge (Euphorbia esula) and water hyacinth (Eichhornia crassipes). In light of these we discuss the assessment of success and impact of biological control programmes, why these aspects are often not adequately addressed, how they might be retroactively addressed and the implications for donor-funding of biological control programmes for developing countries.

Managing risks from pests in global commodity networks - policy perspectives.

Up to 80xa0% of global commodity production comes from smallholdings of less than 0.5xa0ha. Yet commodity crops may be a substantial proportion of a country’s exports, and feed into global supply networks. Pest risks thus have consequences at local, national and global levels. We consider three categories of risk in global commodity networks: introduction of pests to new areas, upsurges of established pests and the risks arising from management efforts. In each category we provide case studies and examples, and consider policy options. Increased travel, trade and transport increase the risks of introduction. Commodity specific biosecurity plans are required for preventing introductions, including analysis of the specific risks (pest pathways) and preparation of emergency responses. Regional and international cooperation is essential. Upsurges can be caused by crop management, evolution of new strains, and environment change. National systems must be responsive to detect problems and address them quickly. Capacity building for surveillance and diagnostics, and the development and dissemination of integrated pest management methods are needed. Investment in research and extension for the agricultural sector is vital. Risks linked with management efforts, specifically, the risk from agrochemicals are considered. Concerns in developed countries over food safety and environmental damage can place constraints on pest management. Failure to comply leads to loss of markets and buyer confidence. Policies that favour lower-risk pest management methods are needed, but are often lacking.

Forecasting the global extent of invasion of the cereal pest Spodoptera frugiperda, the fall armyworm

Fall armyworm, Spodoptera frugiperda, is a crop pest native to the Americas, which has invaded and spread throughout sub-Saharan Africa within two years. Recent estimates of 20-50% maize yield loss in Africa suggest severe damage to livelihoods. Fall armyworm is still infilling its potential range in Africa, and could spread to other continents. In order to understand fall armyworm’s year-round, global, potential distribution, we used evidence of the effects of temperature and precipitation on fall armyworm life-history, combined with data on native and African distributions to construct Species Distribution Models (SDMs). Fall armyworm has only invaded areas that have a climate similar to the native distribution, validating the use of climatic SDMs. The strongest climatic limits on fall armyworm’s year-round distribution are the coldest annual temperature and the amount of rain in the wet season. Much of sub-Saharan Africa can host year-round fall armyworm populations, but the likelihoods of colonising North Africa and seasonal migrations into Europe are hard to predict. South and Southeast Asia and Australia have climate that would permit fall armyworm to invade. Current trade and transportation routes reveal Australia, China, India, Indonesia, Malaysia, Philippines, and Thailand face high threat of fall armyworm invasions originating from Africa.