Serological Identification of Arthropod Bloodmeals and Its Application

Abstract

The yield losses caused by the Asian rice gall midge Orseolia oryzae Wood‐Mason in 15 traditional or high yielding varieties, studied by the paired plot (unprotected and protected) technique, ranged from‐0.06 in CR.1014 to 1.1% in CR.58‐MR.1538 for every unit per cent increase in silver shoots. Based on this, CR.1014 was identified as highly tolerant with no yield loss (‐0.06%) followed by Jagannath with 0.27%, while the other entries were rated as either moderately tolerant (0.3–0.60%) or least tolerant (0.61 % and above).     

International Workshop on the Cassava Mealybug Phenacoccus manihoti M'vuazi,Zaire, June 1977

Abstract

A less labour‐intensive method for mass rearing of Orseolia oryzivora H. &; G. is described. This technique uses a mist chamber system that needs minimal supervision. The complete life cycle of O. oryzivora lasts from 26 to 36 days with a sex ratio of one male to two females. When 23–27 females were released per cage, 100% of the rice plants developed silver shoots. In varietal screenings, three to seven females can be released per cage, resulting in 85–90% infestation of the susceptible cultivars.     

Feasibility of biological control of the sugarcane scale insect Melanaspis gfomerata in India

Abstract

Melanaspis glomerate (Green) is a serious pest of sugarcane in India and does not have effective natural enemies. Parasites of M. smilacis Comst. and M. paulislus Hempel from Brazil and Aphytis mytilaspidis (Le Baron) collected from Aulacaspis tegalensis (Zehnt.) in Mauritius were imported for biological control trials. Only Neococcidencyrtus sp., an endoparasite of M. paulistus accepted M. glomerata. Among the coccinellid predators that were imported only Chilocorus cacti (L.) bred on M. glomerata. The non‐acceptance of this scale insect by most of the introduced natural enemies seems to indicate the need for confirmatory studies on its taxonomic status. Until such time as this is done and suitable natural enemies are found, an integrated approach for its control may have to be considered.     

Estimation of rice yield losses due to the African rice gall midge,Orseolia oryzivora Harris and Gagne

Abstract

The African rice gall midge, Orseolia oryzivora Harris and Gagne (Diptera: Cecidomyiidae), is an important pest of rice, Oryza sativa, in Burkina Faso as well as other countries in West and East Africa. In spite of its importance, little is known regarding the relationship between gall midge populations and grain yield losses. To determine yield losses the gall midge was reared in cages and adult midges were placed on caged plants of the rice variety ITA 123 at different population levels. The seven treatments consisted of different numbers of insects infested on the plants; 0 insect pairs (non‐infested check), and 1, 5, 10, 15, 20 or 25 midge pairs/cage. The loss in yield in relation to the non‐infested control was highly positively correlated (R² = 0.81) with the percentage of gall midge damaged tillers. The infestation by the insect on the plants resulted in the compensatory production of tillers which developed in response to the gall midge damage but the compensation was not sufficient to make up for the loss of yield due to the damaged tillers. Yield loss ranged from 0% in the control to 65.3% in the treatment with 25 pairs of adults. One per cent of tillers damaged resulted in 2% grain yield loss.     

麦红吸浆虫老熟幼虫脱颖规律研究

麦红吸浆虫老熟幼虫的脱颖率与湿度成正比,在湿处理,特别是有水滴的情况下,脱颖率最高;脱颖率与光照强弱成反比,在散射光条件下可以脱颖,黑暗条件下脱颖率最高,强光下基本不脱颖;脱颖率与温度的关系较湿度、光线为小,5～35℃脱颖率均较高,高峰区在7～20℃,最高在10℃左右。     

The phenology and population dynamics of Culicoides spp. in different ecosystems in The Netherlands

The Netherlands has enjoyed a relatively free state of vector-borne diseases of economic importance for more than one century. Emerging infectious diseases may change this situation, threatening the health of humans, domestic livestock and wildlife. In order to be prepared for the potential outbreak of vector-borne diseases, a study was undertaken to investigate the distribution and seasonal dynamics of candidate vectors of infectious diseases with emphasis on bluetongue vectors (Culicoides spp.). The study focused primarily on the relationship between characteristic ecosystems suitable for bluetongue vectors and climate, as well as on the phenology and population dynamics of these vectors.Twelve locations were selected, distributed over four distinct habitats: a wetland area, three riverine systems, four peat land areas and four livestock farms. Culicoides populations were sampled continuously using CO₂-baited counterflow traps from July 2005 until August 2006, with an interruption from November 2005 to March 2006. All vectors were identified to species level. Meteorological and environmental data were collected at each location.Culicoides species were found in all four different habitat types studied. Wetland areas and peat bogs were rich in Culicoides spp. The taxonomic groups Culicoides obsoletus (Meigen) and Culicoides pulicaris (Linnaeus) were strongly associated with farms. Eighty-eight percent of all Culicoides consisted of the taxon C. obsoletus/Culicoides scoticus. On the livestock farms, 3% of Culicoides existed of the alleged bluetongue vector Culicoides dewulfi Goetghebuer. Culicoides impunctatus Goetghebuer was strongly associated with wetland and peat bog. Many Culicoides species were found until late in the phenological season and their activity was strongly associated with climate throughout the year. High annual variations in population dynamics were observed within the same study areas, which were probably caused by annual variations in environmental conditions.The study demonstrates that candidate vectors of bluetongue virus are present in natural and livestock-farm habitats in the Netherlands, distributed widely across the country. Under favourable climatic conditions, following virus introduction, bluetongue can spread among livestock (cattle, sheep and goats), depending on the nature of the viral serotype. The question now arises whether the virus can survive the winter conditions in north-western Europe and whether measures can be taken that effectively halt further spread of the disease.     

国际水稻遗传评价试验网材料对稻褐飞虱和稻瘿蚊的抗性鉴定

对引进的国际水稻遗传评价试验网的材料进行抗稻褐飞虱和稻瘿蚊的抗虫性鉴定,筛选出一批抗稻褐飞虱和稻瘿蚊的品种(材料),其中高抗稻褐飞虱的有IR3383-9-1-13、IR40931-43-2-2-3-2、IR39334-31-2-2-2;高抗稻瘿蚊的有KANGWEN2、ARC5833、DUOKANGI1、ARC5984、RP2572-18-316、RP2337-253-65-11、PHALGUNA、ARC5987。这些材料可供抗稻飞虱和稻瘿蚊育种选用。     

小麦吸浆虫防治技术

小麦吸浆虫属双翅目瘿蚊科,是威胁小麦生产的主要害虫。以幼虫潜伏在小麦颖壳内吸食正在灌浆的麦粒浆液,造成瘪粒、空壳。由于小麦吸浆虫个体小,危害隐蔽,防治技术性强,给小麦生产带来严重威胁。     

小麦吸浆虫幼虫在麦穗上的危害特点及空间分布型研究

为了解小麦吸浆虫幼虫在麦穗上的危害特点及在麦田的空间分布型,在春季越冬幼虫出土期选择小麦吸浆虫越冬基数不等的麦田4块,在籽粒乳熟期调查小麦吸浆虫危害程度的基础上,运用扩散系数、聚集度指标、聚集指数、平均拥挤度、聚块性指标、负二项分布参数等聚集指标及Iwao的x^*x回归法和Taylor 幂函数法,综合分析小麦吸浆虫幼虫在麦穗上的空间分布型。结果表明,小麦吸浆虫的危害程度在田块间差异很大,且危害程度与春季的幼虫越冬基数无关;在麦穗不同部位,总体趋势是上、中部受害程度大于下部,但不同田块之间有差异。以麦穗为单位时,幼虫在麦田的空间分布型属于聚集分布;以麦穗不同部位为单位时,幼虫在麦田的空间分布型也属于聚集分布,且与密度有关。聚集均数λ值的测定结果表明,小麦吸浆虫幼虫的聚集成因主要由自身的生物学特性和环境因素所决定。