麦田食蚜蝇调查及其幼虫捕食作用

食蚜蝇幼虫对麦蚜的控制作用十分明显。为了明确其食蚜蝇的消长动态及捕食作用,1985～1986年,进行了田间调查及室内饲养观察。 1.种类本地区麦田食蚜蝇有;大灰食蚜蝇(Syrphus corollae Fabricius)、斜斑鼓额食蚜蝇(Lasiopticus pyrastri(Lin))、长扁食蚜蝇(Sphaerophoria sp.)、黑带食蚜蝇(Epi-     

大灰食蚜蝇的生物学及对麦蚜控制作用的研究

1984～1987年研究结果表明大灰食蚜蝇在本区一年发生5代,以成虫或老熟幼虫在菜田浅土下越冬。第一、二代幼虫主要发生在麦田,为麦蚜捕食性天敌优势种。幼虫全期捕食量399.38±44.0头,以3龄幼虫捕食量最大。猎物蚜虫密度对捕食量的反应呈负加速曲线,属逆密度制约。田间笼罩试验单头幼虫平均能控制蚜量64.7头,其控制效果为74.8％。并根据蝇蚜比与蚜变系数的直线回归式,确立在现行麦蚜为害损失经济允许阈值小麦扬花、灌浆初期,百株蚜量500～600头,蝇蚜比1:80以下为田间利用指标。经大田验证是符合的。     

斜斑鼓额食蚜蝇末龄幼虫捕食功能的测定

本文采用捕食性天敌日控量的方法,对斜斑鼓额食蚜蝇末龄幼虫的捕食功能进行了测定。初步建立了日控蚜量(y)与苹果黄蚜密度(x)相关数学模型:y=-146.960+4.524x-0.021x~2(r=0.9976 P<0.05),当 x=107.71≈108头时.其最大日控蚜量 y=97头,失控点 x_1=175.6≈176头。     

扬州地区食蚜蝇的研究

扬州地区农田常见食蚜蝇有11种,其中黑带食蚜蝇、门氏食蚜蝇、大灰食蚜蝇、短刺刺腿食蚜蝇、狭带食蚜蝇的发生量最多,是当地的优势种群。食蚜蝇以成虫、老熟幼虫、卵在林木的树皮下,在松柏等常绿树上越冬。黑带食蚜蝇种群密度季节性消长呈马鞍型,门氏食蚜蝇呈抛物线型。温度和天敌是影响种群数量变动的主要原因。食蚜蝇成虫需补充营养,在田间的分布与蚜虫密度、蜜源植物有一定关系。食蚜蝇捕食蚜虫的能力因虫种而异,黑带食蚜蝇、短刺刺腿食蚜蝇、门氏食蚜蝇一生的食蚜量分别为138.7、109.0、75.9头。食蚜蝇是一种捕食能力较强的天敌。     

贵州东部地区茶园的食蚜蝇

１种类据在铜仁、松桃等地调查，该地区发生的食蚜蝇有：狭带食蚜蝇（ＳｙｒｐｈｕｓｓｅｒａｒｉｕｓＷｉｅｄｅｍａｎｎ）、大灰食蚜蝇（Ｓ．ｃｏｒｏｌａｅＦａｂｒｉｃｉｕｓ）、黑带食蚜蝇（ＥｐｉｓｔｒｏｐｈｅｂａｌｔｅａｔａＤｅＧｒｅｅ）、四条小食蚜蝇（Ｐａ...     

大灰食蚜蝇幼虫饲养及温室释放试验

在室内用桃蚜、蔷无网蚜、桃粉大尾蚜、菊花蚜虫4种蚜虫饲养大灰食蚜蝇幼虫取得比较满意的结果,幼虫成活率76～80％,蛹羽化率92～94％,子代卵孵化率84～91％。用豌豆修尾蚜饲养,幼虫成活率仅48％,蛹羽化率50％,子代卵孵化率无明显差异。在大灰食蚜蝇幼虫发育期中,前期用桃蚜饲养,后期改用修尾蚜饲养,对幼虫成活率及蛹羽化率仍有影响.食物(蚜虫)充足时,幼虫自残程度低,可以集体饲养。以1:10的益害比释放大灰食蚜蝇3日龄幼虫,防治非洲菊上的蚜虫,3天后蚜虫下降85.9％,效果显著。     

用不同蚜虫饲养对大灰食蚜蝇生长发育的影响

在室温下分别用甘蓝蚜、豌豆蚜、桃蚜和大麻长管蚜饲养大灰食蚜蝇，幼虫历期分别为10．17天、10．29天、9．16天和9．50天，蛹期分别为8．69天、8．96天、8．46天和7．30天，蛹重分别为32．2毫克、32．3毫克、31．9毫克和26．6毫克，以大麻长管蚜饲养成虫获得率最高，达23．3％，桃蚜最低只有15．1％，研究表明，蚜虫种类对大灰食蚜蝇发育历期、蛹重及存活率有一定影响，人工饲养蚜蝇必需选择适合的蚜种。     

黑带食蚜蝇生物学特性及捕食作用的研究

采用田间调查和室内饲养的方法，研究了黑带食蚜蝇Ｓｙｒｐｈｕｓ ｂａｔｔｅａｔａ的生物学特性和捕食作用。结果表明，该虫每年发生５代，以蛹在土壤中越冬，７－８月则以３代蛹越夏，各龄幼虫对蚜虫的功能反应均为Ｈｏｌｌｉｎｇ－Ⅱ型，随着幼虫的生长，其捕食量逐渐增大。     

用不同蚜虫作猎物对大灰食蚜蝇生长发育的影响

在20～25℃室温下用5种蚜虫分别饲养大灰食蚜蝇的结果表明,用麦长管蚜、禾谷缢管蚜、麦无网长管蚜、豌豆蚜作猎物,均能使食蚜蝇完成发育。幼虫期历期分别为11.0、10.2、10.1和10.6天,发育全期(幼虫+予蛹+蛹期)分别为29.0、30.6、27.4和26.1天,蛹重为33.9～40.7mg,差异不显著。但取食甘蓝蚜的食蚜蝇则不能完成个体发育。每天分别供应5、10、20、40和80头2～3龄麦无网长管蚜饲养食蚜蝇,在5头处理中,幼虫历期明显较长,予蛹及蛹期历期最短,其它4个处理间差异均不显著;幼虫成活率、蛹重和羽化率,则随取食蚜虫量的增加而明显增加。试验结果指出,人工饲养食蚜蝇必需选择适合的蚜种,虽然食蚜蝇幼虫取食86头2～3龄蚜虫即能完成发育,但提供更丰富的猎物还是必要的。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.     

Effect of botanical insecticides and bacterial toxins on the gut enzyme of the rice leaffolderCnaphalocrocis medinalis

The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Insecta: Lepidoptera: Pyralidae) was investigated. Gut enzyme activities were affected by botanical insecticides and bacterial toxin individually and in combination. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins, in bioassays the activities of gut tissue enzymes — acid phosphatases (ACP), alkaline phosphatases (ALP) and adenosine triphosphatases (ATPase) — of rice leaffolder larvae were affected. When combined, the effect was more severe at a low concentration. Larvae that were chronically exposed to botanical insecticides and bacterial toxins showed a reduction in weight (59–89%) and exhibited a significant reduction in ACP, ALP and ATPase activities. The combination ofBacillus thuringiensis kurstaki and botanical insecticides caused a decrease of twofold in enzyme activity even at reduced concentration. A synergistic effect was found when botanical insecticides and bacterial toxins were combined at low doses. These effects were most pronounced in early instars. Clear dose-response relationships were established with respect to enzyme activity. In conclusion: (i) biopesticides are relatively safe and biodegradable; (ii) a synergistic effect of botanical insecticides and bacterial toxins was found; (iii) less expensive, readily available and naturally occurring biopesticides could be an alternative for organic and inorganic pesticides in controlling RLF. http://www.phytoparasitica.org posting Sept. 28, 2004.