Pest risk analysis for Alternanthera philoxeroides

Alternanthera philoxeroides presents a high phytosanitary risk for the EPPO region with a low uncertainty rating. A. philoxeroides is already present in the EPPO region in France and Italy. Further spread within and between EPPO countries is considered likely. The overall likelihood of A. philoxeroides continuing to enter the EPPO region is medium. It is not clear how this species entered the EPPO region and there are no clear pathways of further introduction, as the species is not widely traded as an aquarium plant or as any other type of living plant material. There may be confusion with A. sessilis, or other Alternanthera species traded for aquarium, ornamental or food purposes. The risk of the species establishing in other EPPO countries is considered high as movement through irrigation and river systems may act to connect countries, facilitating spread regionally, especially through high energy unstable river systems that may encourage fragmentation. Spread may be significantly accelerated by water based recreational activities. The potential high impact of the species within the EPPO region should be considered similar to that seen in other countries where the species has invaded and become established; i.e. Australia and the southern states of North America. Impacts are likely to be more pronounced in countries and regions where the climate most suited to population, establishment, growth and spread

Ecological niche and potential geographic distribution of the invasive fruit fly *Bactrocera invadens* (Diptera, Tephritidae)

Two correlative approaches to the challenge of ecological niche modeling (genetic algorithm, maximum entropy) were used to estimate the potential global distribution of the invasive fruit fly, Bactrocera invadens, based on associations between known occurrence records and a set of environmental predictor variables. The two models yielded similar estimates, largely corresponding to Equatorial climate classes with high levels of precipitation. The maximum entropy approach was somewhat more conservative in its evaluation of suitability, depending on thresholds for presence/absence that are selected, largely excluding areas with distinct dry seasons; the genetic algorithm models, in contrast, indicate that climate class as partly suitable. Predictive tests based on independent distributional data indicate that model predictions are quite robust. Field observations in Benin and Tanzania confirm relationships between seasonal occurrences of this species and humidity and temperature

Potential distribution of crop wild relatives under climate change in Sri Lanka: implications for conservation of agricultural biodiversity

The global population is growing rapidly and food production needs to be stepped up substantially to supply the additional demand expected by projected increased population. Further, climate change is expected to exert considerable pressure on global agriculture and food production. Crop wild relatives (CWR), which possess large untapped genetic diversity, can provide vital genetic material for future crop improvement. At present, this important category of plants is at risk due to anthropogenic climate change and other human-mediated changes i.e., habitat destruction. Therefore, it is important to study and understand the vulnerability of CWR to climate change, their potential distribution, and range dynamics for their conservation. Here we use Maxent algorithm to simulate the potential distribution across nine CWR species belonging to four crop genera, Cinnamomum, Piper, Vigna and Oryza in Sri Lanka and investigate how the predicted potential suitable areas change under climate change. Our findings indicate that species response to climate change varies among species studied, even within the same genus. Many species are predicted to decrease their suitable habitat by 2050, suggesting that these species are highly vulnerable to climate change impacts. The study identifies potential CWR rich areas in the country for future in situ conservation. Our findings facilitate decision-makers to make evidence-based decision-making for better management of CWR in Sri Lanka

Biology, Ecology and Management of the Invasive Navua Sedge (Cyperus aromaticus)—A Global Review

Navua sedge (Cyperus aromaticus (Ridley) Mattf. & Kukenth) is an invasive perennial sedge, native to tropical Africa, which is threatening many natural ecosystems and agroecosystems, especially in northern Queensland, Australia. Crop and pasture production have been impacted by Navua sedge and it is also directly causing reductions in dairy and beef production in affected regions. This review documents the biology, ecology and potential management options to minimise the spread and impact of Navua sedge. The weed reproduces both sexually (seeds) and vegetatively (via underground rhizomes). Its tiny seeds can be spread easily via wind, water, vehicles, farm machinery and animals, whilst the rhizomes assist with establishment of dense stands. The CLIMEX model (which uses distribution and climate data in native and novel ranges) indicates that in Australia, Navua sedge has the potential to spread further within Queensland and into the Northern Territory, New South Wales and Victoria. Several management strategies, including mechanical, chemical and agronomic methods, and their integration will have to be used to minimise agricultural production losses caused by Navua sedge, but most of these methods are currently either ineffective or uneconomical when used alone. Other management approaches, including biological control and mycoherbicides, are currently being explored. We conclude that a better understanding of the interaction of its physiological processes, ecological patterns and genetic diversity across a range of conditions found in the invaded and native habitats will help to contribute to and provide more effective integrated management approaches for Navua sedge

Salvinia molesta: An Assessment of the Effects and Methods of Eradication

Salvinia molesta is an invasive aquatic fern. It is now the second worse aquatic invader in the world. Since the 1930s, it has invaded most tropical and some temperate countries. S. molesta plants grow vegetatively and can increase in size rapidly. S. molesta can form thick mats of up to 1-meter-thick. There are a number of ways these thick mats negatively affect the environment: 1) reduce light to benthic organisms, 2) reduce oxygen in the water column for other organisms, 3) accumulate as organic matter at the bottom of the water column, 4) decrease nutrients for other organisms, and 5) change water flow. S. molesta not only degrade and alter ecosystems, infestations also increase public health concerns. Dense S. molesta mats are ideal breeding grounds for mosquitoes and other insects that carry vector-borne diseases. Countries are negatively affected economically because S. molesta hinder use of waterways. Recreational activities, tourism, fishing, and transportation are all impeded due to S. molesta infestations. Methods of control are: 1) physical control, 2) chemical control, and 3) biological control. A combination of two or more methods work best for complete eradication. Biological control is the method of choice in tropical areas. Australia was the first to implement biological control via Cyrtobagous salviniae. C. Salviniae have devastative effects on S. molesta plants because both adults and larvae feed on plant parts. Althought C. savliniae are very effective, they have some constraints: 1) temperature, 2) nutrients, and 3) S. molesata infestation growing stage. S. molesta can withstand lower temperatures than C. salviniae, so in temperate regions, C. salviniae are ineffective. These regions are where other methods of control, such as chemical control, are more effective. C. salviniae also require adequate nitrogen concentration for proper development. S. molesta infestations also need to be in the primary or secondary growing stage for C. salviniae to survive. Tungog Lake in Sabah, Malaysia is heavily infested with S. molesta plants that are in the tertiary growing stage. Mats must first be thinned out via chemical control or mechanical removal. C. salviniae then should be introduced to the lake. Other recommendations for control overall of S. molesta are: 1) more studies in temperate regions should be conducted at specific infestation sites, 2) increase public education to reduce use of S. molesta as an ornamental, and 3) ban cultivation sites and sales