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1.
In this article, we review studies of the ecology of the larger grain borer, Protephanus truncatus, both outside and within the maize storage systems. Laboratory studies have shown that P. truncatus can breed on a wide range of woody substrates (branches, roots, and seeds). Pheromone trap catches in different habitats strongly suggest that P. truncatus is well-established in certain non-agricultural environments, presumably breeding in dead or dying wood. In Meso-America, West and East Africa, P. truncatus reproduction in the field has been documented in branches ring-barked by cerambycid beetles. Within a maize store, P. truncatus densities can increase from very small initial colonies of probably less than 200 individuals to densities in excess of 1000 beetles per kg after about 4–6 months of storage. Insect parasitoids are very often found in smallholders' grain stores attacked by P. truncatus, but they do not contribute significantly to population regulation. Declines in maize store population levels in Benin from 1993 to 1996, and in adult abundance in pheromone traps in the natural environment in Kenya, have been attributed to predation by the introduced predator, Teretrius nigrescens, but in recent years pheromone trap catches in West Africa suggest that the situation may be complex. Several environmental factors, notably temperature, humidity, and daylength, and their interactions, have been correlated with P. truncatus flight activity, as well as, in West Africa, the emptying of maize stores. Laboratory experiments have shown food quality also affects flight activity. Factors terminating dispersal and flight are most likely attraction to the male-released aggregation pheromone. Short range attraction to plant volatiles has also been recorded. In Africa the highest densities of P. truncatus tend to occur in humid lowlands, which contrasts with the situation in meso-America where P. truncatus tend to occur in greatest numbers in cooler upland regions. Pheromone trap catches can be significant predictors of the risk of stores becoming infested. Coupled with the development of a rule-based model of flight activity, these studies may offer the prospect of predicting the risk of store infestation based upon temperature and humidity measurements.  相似文献   

2.
Biological control was first considered shortly after the accidental introduction of Prostephanus truncatus in Africa in the early 1980's. This article reviews first the history of the biological control efforts with a focus on the results and recommendations of the initial international meetings and foreign exploration projects, followed by a discussion of the more important biocontrol agents, in particular the histerid Teretrius nigrescens. Since the release of T. nigrescens in Africa a number of techniques have been employed by different research groups to measure the effect of the natural enemy on P. truncatus, including pheromone trapping, field experiments, gut analysis grain store surveys, simulation modelling, and statistical and economic analysis the conclusions of these various studies have been largely equivocal, and the results of studies with recent data suggest that uncertainty is growing. Further resources and time are needed both for a proper evaluation and for the further development of control strategies compatible with biological control.  相似文献   

3.
Methods for detecting and for monitoring Prostephanus truncatus(Horn) are crucial components in phyto- sanitary control, research programmes and pest management against this beetle. P. truncatus is unusual in that its populations are distributed widely between natural habitats and stores holding maize grain and dried cassava roots, which necessitates a similarly wide range of sampling methodologies. This review considers successful and unsuccessful approaches to sampling the pest populations in both stores and the natural environment and concludes with a consideration of how monitoring could contribute to integrated pest management for P. truncatus.  相似文献   

4.
间作大蒜对茄子截形叶螨的防控效果   总被引:1,自引:0,他引:1  
为明确间作大蒜对茄子截形叶螨Tetranychus truncatus Ehara种群的防控效果,于室内测定了大蒜提取液对截形叶螨卵的毒杀活性及对雌成螨的驱避和产卵选择性影响,并研究了田间不同比例间作大蒜对茄子截形叶螨自然种群的影响。结果表明,用0.05 g/mL和0.10 g/mL大蒜提取液处理后,截形叶螨卵死亡率分别为44.53%和63.53%,均显著高于空白对照;大蒜提取液处理蔬菜叶片72h后,截形叶螨雌成螨和卵的数量分别为16头和141粒,均显著低于空白对照组的23头和236粒;田间茄子和大蒜按1∶1、2∶1或4∶1间作均可降低截形叶螨自然发生数量,其中1∶1和2∶1间作对截形叶螨种群控制显著升高。研究表明,大蒜提取液对截形叶螨雌成螨取食及产卵具有显著的驱避活性;且间作大蒜可以对截形叶螨种群起到明显的抑制作用。  相似文献   

5.
The establishment of P. truncatus in Africa has highlighted the inherent weakness of phytosanitary measures against exotic pests. Consideration is given to the need for phytosanitary measures and how patterns of international trade affect phytosanitary control. To prevent the spread of pests such as P. truncatus, large grain shipments can be subject to stringent pest control procedures. However, a significant proportion of grain movement in Africa, both within countries and across borders, occurs informally by both illicit, commercial movement of multiple truckloads of grain and legally by individuals carrying headloads via bush paths or small parcels on public transport. Attempts to locate and inspect the small lots would be impractical. Some recommendations are given on how the spread of P. truncatus in large-scale international trade can be slowed but otherwise it is accepted that in the long-term the prevention of further spread of P. truncatus in Africa is wholly unrealistic.  相似文献   

6.
为明确新型复配杀螨剂联肼·乙螨唑对目前蔬菜田常发生的2种优势叶螨二斑叶螨Tetranychus urticae和截形叶螨T. truncatus的杀螨活性,于室内采用离体叶碟法测定其对这2种叶螨产卵及发育的影响,于室外采用活体植株评价该药剂对2种叶螨的田间防效。结果表明,经复配杀螨剂联肼·乙螨唑及其单剂处理2种叶螨雌成螨24 h后,死亡率为20.50%~54.98%,均显著高于清水对照;联肼·乙螨唑处理较清水对照显著降低了2种叶螨卵发育至若螨期的比率,联肼·乙螨唑处理后二斑叶螨和截形叶螨的若螨率分别为4.91%和1.63%。田间试验中联肼·乙螨唑对2种叶螨具有一定的速效性,药后3 d对二斑叶螨和截形叶螨的防效分别达95.74%和89.83%,药后7 d防效分别为98.03%和99.44%,显示了优良的防控效果及持效性。表明复配杀螨剂联肼·乙螨唑可用于田间蔬菜优势叶螨种群的高效防控。  相似文献   

7.
The story of Prostephanus truncatus in Africa is described from its original outbreak in Tanzania in the late 1970s to the present day. Information is given on the differing control methods put in place by infested countries and how co-ordination of local programmes and inputs from technical assistance agencies was approached by an agencies. The influence of changes in development thinking on the management of storage pests is considered. The current status of P. truncatus is addressed, inlcuding its impact on the international maize trade, particularly that provided for famine relief. The introduction of Teretrius nigrescens as a biological control agent is described. We also provide some milestones in efforts to manage the pest, describe the effectiveness of pest management in terms of cost benefit and suggest some new avenues that may lead to a sustainable reductioning in P. truncatus in Africa.  相似文献   

8.
Barley yellow dwarf (BYD) is one of the main viral diseases of small-grain cereals. This disease, reported on numerous plant species of the Poaceae family, is caused by a complex of eight viral species including the species Barley Yellow Dwarf Virus-PAV (BYDV-PAV), frequently found in western Europe. Resistance sources against BYDV-PAV are scarce and only identified in perennial Triticineae. Some BYDV-resistant wheat lines have been obtained by introgressing these resistances into bread wheat germplasms. Genetic and biological characterization of the resulting lines has been undertaken. However, little information on the resistant behaviour of these lines during the early stages of the infection process is available. To evaluate the resistance of two genetically distinct resistant lines (Zhong ZH and TC14), 1740 young plantlets, belonging to susceptible reference hosts (barley cv. Express and wheat cv. Sunstar), Zhong ZH or TC14 wheat lines, were inoculated in controlled conditions with French BYDV-PAV isolates. The infection process was monitored during the first 21 days after inoculation (DAI) using a semi-quantitative ELISA. A standardized protocol including five successive samplings of leaves from all inoculated plants and the collection of plant roots at the end of the monitored period was carried out. This protocol enabled an assessment of the infection percentage and the evolution of the viral load in plants from the 7th DAI to the 21st DAI. Statistical analyses of the BYDV infection kinetics using raw ELISA data, a model of the time-dependent variation of the percentage of infected plants and the area under concentration progress curves (AUCPC) demonstrated that Zhong ZH and TC14 lines (1) reduce the development rate of the BYD disease during the first days of infection, (2) decrease the infection efficiency of BYDV-PAV isolates, in the leaves, from 98.7% for susceptible plant genotypes to 81.9% and 71.7% for Zhong ZH and TC14, respectively, (3) reduce the virus load in the leaves of infected plants and (4) are not spared from BYDV infection, as 95.1% of Zhong ZH and 90.2% of TC14 inoculated plants accumulated viral particles in roots and/or in leaves at 21 DAI. These results confirm the BYDV-partial resistant behaviour of both Zhong ZH and TC14 lines. The development rate of the disease was the single parameter that allowed the distinction between the two resistant sources present in the tested lines.  相似文献   

9.
The use of hydrogenated rapeseed oil as a carrier for conidia of the entomopathogenic fungus Beauveria bassiana (Bals) Vuill was investigated as part of a research programme on the control of the larger grain borer, Prostephanus truncatus (Horn). Melting the oil, which is solid at temperatures below 32 °C, allows the incorporation of materials such as aggregation pheromones and conidia; sudden cooling produces solid fat pellets. In attraction tests conducted with pellets containing P truncatus aggregation pheromone, significantly higher numbers of beetles were attracted to pellets containing pheromone at a concentration of 4 ml litre−1 compared to control pellets for at least four weeks when held in Petri dishes in the laboratory and for at least six weeks when pellets held in insect traps were exposed to outside conditions. The attraction was retained over a period of storage in glass bottles; pellets stored in the freezer or incubator (at −10 °C or 27 °C) attracted beetles according to the pheromone level for the duration of the work (14 and 13 months respectively). When pheromones and conidia were incorporated into the same pellets they could be stored in a freezer or refrigerator retaining over 80% viability after 51 weeks; those stored in an incubator at 27 °C showed significantly lower germination at 20.7–27.2% after the same time. There was an indication that the pheromone caused a slight reduction in the viability of conidia, although this may have been just a slight delay in the speed of germination. Rapid dose transfer from pellets with conidia with and without the addition of pheromone was demonstrated. Insects were exposed to pellets for 24 hours and 96–100% mortality was observed in treatments containing conidia within six days of exposure. © 1999 Society of Chemical Industry  相似文献   

10.
Mungbean yellow mosaic virus (MYMV) disease is one of the most vicious diseases of green gram and has been renowned in India for more than five decades. It is caused by a group of geminiviruses belonging to the genus, begomovirus of the family, Geminiviridae. They are transmitted through whitefly in a persistent manner. The economic losses due to this virus account up to 85% in green gram which is spreading faster towards newer areas. The escalating economic importance of MYMV has resulted in the call for accurate detection and identification procedures that inspire rigorous research efforts focussing on the biology, diversity and epidemiology of the virus, so that viable management strategies could be designed. Breeding for resistance or tolerance appears to be the best approach to control this disease. However, the commercially offered genotypes are only partially resistant. Therefore, the hunt for newer sources of disease resistance needs to be intensified. This review updates all the accessible information on MYMV and outlines the areas in which advance research is indispensable.  相似文献   

11.
The first parasitoid species reared from a population of the cedar aphid,Cinara cedri Mimeur, 1935 (Hemiptera: Aphididae), from the peninsula of Anatolia in Turkey is described.Pauesia anatolica (Hymenoptera: Braconidae, Aphidiinae) is closely related to some species of thelaricis group ofPauesia from which it differs in the number of antenomers, the propodeum and features of the female genitalia. Its potential use as a natural enemy in areas where the aphid has been introduced is discussed. http://www.phytoparasitica.org posting Aug. 28, 2005.  相似文献   

12.
引起甘蔗花叶病的病原分子生物学进展   总被引:2,自引:1,他引:1  
花叶病是最主要的甘蔗病毒病害之一,在全球种植甘蔗的国家或地区普遍发生,可导致甘蔗产量下降,糖分减少,给甘蔗生产带来严重的经济损失。引起甘蔗花叶病的病毒主要有甘蔗花叶病毒(Sugarcane mosaic virus,SCMV)、高粱花叶病毒(Sorghum mosaic virus,Sr MV)和甘蔗条纹花叶病毒(Sugarcane streak mosaic virus,SCSMV)。本文综述了这3种病毒的生物学特性、鉴定与检测、基因组结构与基因功能、遗传变异与分子进化等方面的研究进展,并讨论了对甘蔗花叶病的生态防控措施。  相似文献   

13.
14.
Abstract

Knockdown, mortality and residual activity of pyrethrins and cyfluthrin were studied on the larger grain borer (LGB), Prostephanus truncatus (Horn). Pyrethrum marc with 0.4% pyrethrins and cyfluthrin dust (0.1% a.i.) when applied on filter paper at 0.72 mg/cm2 gave 98.6% and 100% knockdown (KD) respectively after 6 h. Cyfluthrin dust had a faster KD effect with 100% KD compared to 93.1% for pyrethrum marc, ½1/2>h after treatment. After 24 h there was no recovery from KD in both treatments. After 72 h, 23.2% of the LGB had recovered from KD while mortality was 76.8% in the pyrethrum marc treatment. After the same period, cyfluthrin resulted in 100% mortality. Mortality of P. truncatus exposed to different dosages of cyfluthrin dust in shelled maize was less than 100% at dosages lower than 1 part per million (ppm) but was 100% at 1 ppm and higher dosages 3 days after treatment. Progeny emergence was suppressed at all dosage levels above 0.25 ppm compared to a mean progeny of 68.8 in the check after 45 days. Cyfluthrin dust was more residually toxic at 0.5 ppm and higher dosages, with mortality of >90% at 5 months after treatment. This suggests that cyfluthrin dust at 0.1% a.i. mixed with shelled maize at 1 ppm will give protection and control of LGB infestation.  相似文献   

15.
Five invasive species of longhorn beetles, all known as pests and originating from different geographical areas, are recorded from Israel for the first time:Phoracantha recurva (Newman) andXystrocera globosa (Olivier) were collected in nature;Chlorophorus annularis (Fabricius),Neoplocaederus basalis (Gahan) andRhagium inquisitor (Linnaeus) were reared from imported timber. http://www.phytoparasitica.org posting May 29, 2008.  相似文献   

16.
Tobacco streak virus in sunflower (Helianthus annuus)   总被引:1,自引:0,他引:1  
Tobacco streak virus (TSV) was isolated from a plant of sunflower (Helianthus annuus) showing severe necrosis and chlorosis in the leaves. The virus was identified as TSV by serology and, to some extent, by host range. The type of symptoms varied with the host plant in which the virus had been propagated in successive transfers. Test plants inoculated with the virus propagated inNicotiana rustica produced symptoms which very much differed from those brought about by the virus from eitherN. clevelandii orChenopodium amaranticolor.The significance of the host-mediated variation in symptoms is discussed.Samenvatting Tabaksstrepenvirus (TSV) werd geïsoleerd uit zonnebloem (Helianthus annuus) die sterke necrose en chlorose van de bladeren vertoonde. De identiteit van het virus werd vastgesteld op grond van serologische reacties en, tot op zekere hoogte, de symptomatologie. Het type symptoom op de toetsplanten bleek echter sterk afhankelijk te zijn van de plant waarvan het inoculum afkomstig was. Was het virus verschillende malen achtereen vermeerderd inNicotiana rustica dan waren de symptomen op de toetsplanten zeer verschillend van die, welke werden veroorzaakt door virus vermeerderd inN. clevelandii ofChenopodium amaranticolor. De betekenis van deze door de waardplant bewerkstelligde variatie in symptomen wordt besproken.  相似文献   

17.
In autumn 2007, an allium leafminer, Phytomyza gymnostoma Loew (Diptera: Agromyzidae), was recorded for the first time in non‐commercial leek crops in the areas of Elassona and Katerini in Central Greece. Leek plants were severely damaged by the leafminer larvae infestation. Typical feeding symptoms were observed, caused by the mining behaviour of larvae within inner and outer leaves of leek plants, resulting in the formation of descending galleries. Pest control was performed locally using commercial insecticides with unknown efficacy mainly due to ignorance of the species biology.  相似文献   

18.
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.  相似文献   

19.
The Coccoidea of cultivated and non-cultivated areas of Ankara Province, in central Anatolia, Turkey, were surveyed between 1999 and 2001. Eleven species of Eriococcidae were collected, of which nine are new records for Turkey:Acanthococcus greeni Newstead,A. micracanthus Danzig,A. munroi Boratynski,A. roboris (Goux),A. zernae Tereznikova,Rhizococcus cingulatus (Kiritchenko),R. cynodontis (Kiritchenko),R. herbaceus Danzig andR. pseudinsignis (Green). http://www.phytoparasitica.org posting Sept. 30, 2003.  相似文献   

20.
Alternaria solani causes diseases on foliage (early blight), basal stems of seedlings (collar rot), stems of adult plants (stem lesions), and fruits (fruit rot) of tomato. Early blight is the most destructive of these diseases and hence receives considerable attention in breeding. For over 60 years, breeding for early blight resistance has been practiced, but the development of cultivars with high levels of resistance has been hampered by the lack of sources of strong resistance in the cultivated tomato and by the quantitative expression and polygenic inheritance of the resistance. In some accessions of wild species, high levels of early blight resistance have been found, but breeding lines still have unfavorable horticultural traits from the donor parent. Recently, the first linkage maps with loci controlling early blight resistance have been developed based on interspecific crosses. These maps may facilitate marker-assisted selection. This overview presents the current knowledge about the A. solani–tomato complex with respect to its biology, genetics, and breeding.  相似文献   

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