The potential distribution of an invasive mealybug Phenacoccus solenopsis and its threat to cotton in Asia

• 1 In recent years, an invasive mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) has attacked cotton (Gossypium hirsutum L.) in Pakistan and India, causing severe economic losses. This polyphagous pest was probably introduced accidentally from North America. Infestations have broken out suddenly and spread rapidly.
• 2 Seasonal and annual population growth data of P. solenopsis from nine locations in its native range in the U.S.A., and the distribution of the mealybug worldwide, were analyzed using the CLIMEX model. This indicated that tropical regions worldwide were highly suitable for P. solenopsis.
• 3 Its potential distribution was limited by cold in high latitudes and altitudes, and dryness in northern Africa, inland Australia and parts of the Middle East. CLIMEX was used to predict where P. solenopsis might establish, and to estimate the potential threat to cotton yield in Asia. The key limiting factors were low precipitation as well as minimum temperatures in northern areas.
• 4 When irrigation was factored into the simulation, the potential distribution of P. solenopsis expanded dramatically, indicating that P. solenopsis presents a great economic threat to cotton in Asia and other parts of the world.

     

Potential distribution of the Asian disease vector Culex gelidus Theobald (Diptera: Culicidae) in Australia and New Zealand: a prediction based on climate suitability

Abstract  Culex gelidus has a wide distribution throughout Asia, where it is a vector of Japanese encephalitis. It was first detected in Australia in 1999, with archived material revealing an introduction sometime prior to 1994. It is currently widely distributed throughout northern and particularly north-eastern Australia. Using climate matching software (CLIMEX Version 1.1) and the known distribution of Cx. gelidus throughout Asia, a predicted distribution for Australasia based on current climate was developed. A potentially wide distribution throughout coastal Australia, particularly in tropical and subtropical areas, was revealed. Few inland locations were suitable, except in tropical areas of the Northern Territory and Queensland. The predicted distribution presented here is concordant with most recent collection records of Cx. gelidus in Australasia. However, there are a small number of exceptions which highlight some of the limitations of this approach for predicting mosquito distributions. The presence of Cx. gelidus in a large artificial swamp in Alice Springs is one such example. The predicted Cx. gelidus distribution incorporates highly populated areas, in which people may experience an increased risk of mosquito-borne viral encephalitis should this mosquito spread throughout its entire predicted range.     

Factors affecting the distributions of the ticks Amblyomma hebraeum and A. variegatum in Zimbabwe: implications of reduced acaricide usage

The ticks Amblyomma hebraeum and A. variegatum are the main vectors of heartwater, a disease of ruminants caused by Cowdria ruminantium, in the agricultural areas of Zimbabwe. At present, A. hebraeum is widely distributed in the dry southern lowveld, and occurs in at least seven foci in the higher rainfall highveld. Amblyomma variegatum occurs in the Zambezi valley and surrounding dry lowveld areas in the northwest. The distribution of A. hebraeum has changed considerably over the past 70 years, while that of A. variegatum appears to have remained fairly static. The distribution patterns of both species in Zimbabwe display anomalous features; the ticks occur in areas of lowest predicted climatic suitability for survival and development and in areas where the densities of cattle, the most important domestic host, are lowest. The only factor favouring the survival of the species in the lowveld habitats in which they occur is the presence of alternative wildlife hosts for the adult stage. Their absence from more climatically favourable highveld habitats appears to have been the result of intensive acaricide treatment of cattle over a long period and a historic absence of significant numbers of wildlife hosts. Eradication of A. hebraeum and A. variegatum by intensive acaricide treatment of cattle can be achieved in the absence of significant numbers of alternative hosts, because of the long attachment and feeding periods of the adults of these tick species. However, eradication becomes impossible when alternative hosts for the adult stage are present, because a pheromone emitted by attached males attracts the unfed nymphal and adult stages to infested hosts. The unfed ticks are not attracted to uninfested hosts, such as acaricide-treated cattle.Regular acaricide treatment of cattle is expensive and so, for economic reasons, the Government of Zimbabwe is no longer enforcing a policy of strict tick control. It is likely that reduced tick control will result in the spread of Amblyomma ticks to previously uninfested areas. Added to this, recent introductions of various wildlife species to highveld commercial farming areas have created conditions in which the ticks could become established in higher rainfall areas. Amblyomma hebraeum is more likely to spread than A. variegatum, because its adults parasitize a wider range of wildlife hosts (warthogs, medium to large-sized antelope, giraffe, buffalo and rhinoceros), whereas adults of A. variegatum appear to be largely restricted to one wildlife species (buffalo) in Zimbabwe, the distribution of which is now confined to very limited areas of the country, as part of foot and mouth disease control measures. A model to predict the rate of spread of A. hebraeum through the highveld is described.Possible control options for dealing with the spread of Amblyomma ticks and heartwater to previous unaffected highveld areas, include (1) continuation of intensive acaricide treatment of cattle to prevent the spread, (2) establishment of a buffer zone of intensive tick control around affected areas to contain the spread and (3) allow the spread to occur and control heartwater by means of immunization. An economic analysis to determine the costs and benefits of the control options, which takes into account the development of Amblyomma-specific tick control technologies and improved heartwater vaccines, is recommended.Deceased.     

Populations of North American bean thrips, Caliothrips fasciatus (Pergande) (Thysanoptera: Thripidae: Panchaetothripinae) not detected in Australia

Abstract  Caliothrips fasciatus is native to the USA and western Mexico and overwintering adults are regular contaminants in the 'navel' of navel oranges exported from California, USA to Australia, New Zealand and elsewhere. Due to the long history of regular interceptions of C. fasciatus in Australia, a survey for this thrips was undertaken around airports, seaports, public recreational parks and major agricultural areas in the states of Queensland, New South Wales, Victoria, South Australia and Western Australia to determine whether C. fasciatus has successfully invaded Australia. Host plants that are known to support populations of C. fasciatus , such as various annual and perennial agricultural crops, urban ornamentals and weeds along with native Australian flora, were sampled for this thrips. A total of 4675 thrips specimens encompassing at least 76 species from a minimum of 47 genera, and three families were collected from at least 159 plant species in 67 families. Caliothrips striatopterus was collected in Queensland, but the target species, C. fasciatus , was not found anywhere. An undescribed genus of Thripidae, Panchaetothripinae, was collected from ornamental Grevillea (var. Robyn Gordon) at Perth (Western Australia) Domestic Airport, and is considered to be a native Australian species. This survey has provided valuable information on the background diversity of thrips species associated with various native and exotic plant species around major ports of entry and exit for four of five states in Australia. We suggest that the major reason C. fasciatus has not established in Australia is due to high adult mortality in navels that are kept at low storage temperatures (2.78°C) during an 18- to 24-day transit period from California to Australia.     

Introduction, Rearing, and Host Range of Aerenicopsis championi Bates (Coleoptera: Cerambycidae) for the Biological Control of Lantana camara L. in Australia

The biology and host range of the cerambycid beetle Aerenicopsis championi Bates, a potential biological control agent for the weed Lantana camara L., were studied. A. championi is a univoltine species associated with L. camara, L. urticifolia, and L. hirsuta in Mexico and Central America. In Mexico, adult emergence occurred in May and June at the start of the rainy season. Larvae fed within the stems over a 9- to 12-month period and caused damage to the plant. The insect was imported into Australia, where a procedure for rearing it in the laboratory was developed. Host-range tests indicated that adults oviposited and larvae commenced development in L. camara and L. montevidensis but not in any of 57 other species tested. A CLIMEX model indicated that most areas infested with lantana in Australia would have a favorable climate for A. championi. Permission to release this insect in Australia was obtained and three small releases were made in southern Queensland in February 1995.     

Vorkommen und potenzielle Verbreitung des Rispenkrauts (Iva xanthiifolia) in ?sterreich

Iva xanthiifolia Nutt. is an annual species originating from North America that has been first introduced to Europe in the mid nineteenth century. The plant has successfully established mainly in Eastern Europe, where it threatens to become a human health problem because of the allergenic pollen produced by this species. The aim of the study was to reconstruct the colonisation of this species in Eastern Europe and to map its current distribution in Austria based on literature information. In addition, the potential distribution in Austria was assessed using a climate-matching approach. Today, I. xanthiifolia is actively spreading particularly in Hungary, Serbia and Bulgaria. In Austria, the plant occurs only rarely and casually as a ruderal plant mainly in towns, train stations and along railway tracks. Results of a climate matching simulation show that most parts of Austria are outside of the climatic range of I. xanthiifolia. However, the warm and continentally influenced eastern parts of Austria are climatically highly suitable for I. xanthiifolia. Small populations of I. xanthiifolia are already present in this region. In addition, further introductions of I. xanthiifolia in these regions is likely either by natural dispersal from well established population in the neighbouring countries (e.g. Slovakia, Czech Republic), or through contaminated grain imports and bird seed. Because of the potential impact of I. xanthiifolia to human health, establishment and spread of the plant should be monitored and strategies for containment and control should be implemented.     

Modelling the potential distribution of the invasive tomato red spider mite, <Emphasis Type="Italic">Tetranychus evansi</Emphasis> (Acari: Tetranychidae)

Predicting the potential geographical distribution of a species is particularly important for pests with strong invasive abilities. Tetranychus evansi Baker & Pritchard, possibly native to South America, is a spider mite pest of solanaceous crops. This mite is considered an invasive species in Africa and Europe. A CLIMEX model was developed to predict its global distribution. The model results fitted the known records of T. evansi except for some records in dry locations. Dryness as well as excess moisture stresses play important roles in limiting the spread of the mite in the tropics. In North America and Eurasia its potential distribution appears to be essentially limited by cold stress. Detailed potential distribution maps are provided for T. evansi in the Mediterranean Basin and in Japan. These two regions correspond to climatic borders for the species. Mite establishment in these areas can be explained by their relatively mild winters. The Mediterranean region is also the main area where tomato is grown in open fields in Europe and where the pest represents a threat. According to the model, the whole Mediterranean region has the potential to be extensively colonized by the mite. Wide expansion of the mite to new areas in Africa is also predicted. Agricultural issues highlighted by the modelled distribution of the pest are discussed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Biology and host range of Ophiomyia camarae Spencer (Diptera: Agromyzidae), a potential biocontrol agent for Lantana spp. (Verbenaceae) in Australia

The life history and host range of the herringbone leaf-mining fly Ophiomyia camarae, a potential biological control agent for Lantana spp., were investigated. Eggs were deposited singly on the underside of leaves. Although several eggs can be laid on a single leaf and a maximum of three individual mines were seen on a single leaf, only one pupa per leaf ever developed. The generation time (egg to adult) was about 38 days. Females (mean 14 days) lived longer than males (mean 9 days) and produced about 61 mines. Oviposition and larval development occurred on all five lantana phenotypes tested. Eleven plant species representing six families were tested to determine the host range. Oviposition and larval development occurred on only lantana and another nonnative plant Lippia alba (Verbenaceae), with both species supporting populations over several generations. A CLIMEX model showed that most of the coastal areas of eastern Australia south to 30°16′ S (Coffs Harbour) would be suitable for O. camarae. O. camarae was approved for release in Australia in October 2007 and mines have been observed on plants at numerous field sites along the coast following releases.     

刺槐叶瘿蚊在中国的危险性评估

采用CLIMEX模型预测分析了刺槐叶瘿蚊Obolodiplosis robiniae(Haldemann)在中国的潜在地理分布,并参照我国有害生物危险性定量分析方法,对刺槐叶瘿蚊在中国的危险性作出综合评价.结果表明:刺槐叶瘿蚊在中国潜在的分布区范围是98 30°～132.03°E,24.23°～47.41°N.最宜适生区(EI ≥ 15)包括华北、华中、华南及云南大部分地区;适生区(5 ≤ EI＜15):包括辽宁和河北中南部,山西及陕西南部,四川、甘肃东南部分地区;半适生区(0 ＜ EI ＜ 5):包括黑龙江、吉林、四川大部分地区及西藏、甘肃、宁夏部分地区;其余各地的EI值均小于等于0,属于非适生区.预测其在中国的风险值为2.26,根据国际上风险值分级标准,属于高度危险生物.据此提出了针对性的风险管理措施.     

低温条件下松材线虫在中国的风险分布区预测

【目的】松材线虫是我国一种重要的检疫性外来入侵物种,给我国林业造成巨大的经济损失。近年来在松材线虫疫区的调查发现,一些年平均温度8℃左右的高海拔地区也开始有松材线虫病的发生,说明其分布线可能开始向北和高海拔地区移动。因此,在松材线虫低温适应性驯化环境下,对松材线虫在我国的最新风险分布区进行了预测。【方法】将松材线虫分为长期(30 d)暴露和短期(24 h)暴露2组进行低温(3、1、0、-1、-3、-5、-6、-7、-9、-12℃)暴露实验,得出致死温度LT50、LT75和LT99。利用CLIMEX 1.0适生性分析软件与Arc GIS 10.2地理信息系统软件以LT50、LT75和LT99为界限划分风险分布区。利用CLIMEX软件导入新的温度数据对松材线虫进行适生性分析,将结果导入Arc GIS中,进行IDW插值,以EI值划分松材线虫风险分布区。对有无低温胁迫及不同低温胁迫时间下的中度风险分布北线的变化趋势进行分析。【结果】松材线虫长期冷胁迫(30 d)条件下的中度风险分布区界线比短期冷胁迫(24 h)条件下和无胁迫条件下(以EI值划分)的中度风险分布区界线明显靠北。【结论】随着低温胁迫时间的延长,松材线虫分布区有向北扩散的趋势,即产生一定的低温适应性进化。