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柑桔黄龙病的病原在木虱体内循回期的研究 总被引：3，自引：0，他引：3
本研究应用生物测定和电镜检验的方法,探讨黄龙病病原在其介体昆虫(柑桔木虱)体内的循回期。前者的结果表明,其循回期长短不一,短的为3天或少于3天,长的达26—27天。木虱成虫能终身携带病原。获“毒”饲育若虫新羽化的成虫也能传病。其中,羽化后1天和2—5天便能传病的单虫分别占供试虫(组)数的3%和5%。电镜检验结果,在获“毒”饲育后3天的成虫唾液腺细胞内能观察到病原体,有力支持了采用生物测定循回期的可靠性。根据由获“毒”饲育若虫新羽化的成虫就能传病的新认识,建议治虫防病的重点应放在治卵和若虫上。 相似文献
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柑桔木虱生物学特性及防治研究 总被引：14，自引：1，他引：14
柑桔木虱雌成虫必须选择寄主嫩梢产卵的特性与年发生代数关系密切。其嗜好寄生九里香,九里香年抽梢次数比柑桔多,在九里香上1年可能发生9—11代,在柑桔上可能发生6—7代(福州地区)。春夏秋季(旬严均气温分别为19.6℃、28℃和24℃)最长与平均成虫寿命及世代历期分别为98天、40天和52—59天;59天、32天和18—22天;65天、30天和25—30天。越冬成虫寿命长达260天。若虫和成虫的致死“温/时”分别为—3℃/小时和—10℃/小时。40％氧化乐果的800—1000倍液对木虱有特效,专性杀螨剂托尔克和普特丹对木虱无兼治作用。 相似文献
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本研究应用生物测定和电镜检验的方法,探讨黄龙病病原在其介体昆虫(柑桔木虱)体内的循回期。前者的结果表明,其循回期长短不一,短的为3天或少于3天,长的达26-27天。木虱成虫能终身携带病原。获"毒"饲育若虫新羽化的成虫也能传病。其中,羽化后1天和2-5天便能传病的单虫分别占供试虫(组)数的3%和5%。电镜检验结果,在获"毒"饲育后3天的成虫唾液腺细胞内能观察到病原体,有力支持了采用生物测定循回期的可靠性。根据由获"毒"饲育若虫新羽化的成虫就能传病的新认识,建议治虫防病的重点应放在治卵和若虫上。 相似文献
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异色瓢虫成虫对枸杞木虱的捕食作用 总被引：2，自引：0，他引：2
为测定异色瓢虫Harmonia axyridis(Pallas)成虫对枸杞木虱Paratrioza sinica YangLi的捕食作用,在室内测定了异色瓢虫成虫的捕食功能反应、种内干扰、自身密度干扰及捕食偏好性,并通过罩笼试验调查了异色瓢虫成虫对枸杞木虱的田间防控效果。结果表明,异色瓢虫成虫对枸杞木虱的捕食功能反应符合Holling Ⅱ型方程,对卵、1~2龄若虫、3~5龄若虫以及成虫的最大捕食量分别为111.5粒、511.6头、254.2头和113.6头。在异色瓢虫成虫生长周期30 d内能使枸杞木虱总虫口密度下降76.6%;对1~2龄枸杞木虱若虫的搜寻效率为1.01,处理时间为0.0020,均高于卵、3~5龄若虫与成虫;在150头/皿的猎物密度下,异色瓢虫成虫的最大捕食率达85.6%,益害比参考值为1∶150。异色瓢虫成虫对枸杞木虱的捕食作用受自身密度的影响显著大于种内干扰;在100头/皿混合猎物密度下,异色瓢虫成虫更偏好捕食木虱成虫,在300头/皿猎物密度下,异色瓢虫成虫更偏向于1~2龄若虫。研究表明,异色瓢虫成虫是具有控制潜力的捕食性天敌,人工释放异色瓢虫成虫可有效防控枸杞木虱。 相似文献
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三种瓢虫对木虱成虫的捕食量观察 总被引：9，自引：1，他引：9
六斑月瓢虫Menochilus sexmuculatus、红星盘瓢虫Phry(?)ocaria congener和龟纹瓢虫Propylaea japonica成虫的捕食能力与柑桔木虱Diaphorina citri成虫密度呈负加速曲线型,符合Holling圆盘方程Na=(a′TN)/(1+a′TnN)。三种瓢虫成虫对柑桔木虱成虫功能反应的线性方程分别为1/Na=1.0735(1/N)+0.0105,1/Na=1.5909(1/N)=0.01119和1/Na=1.03431/N+0.007727。根据方程可得三种瓢虫成虫对柑桔木虱成虫一昼夜捕食量的上限分别为95.2头,89.4头和129.4头。 相似文献
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本试验在福建省福州市及广东省侥平县两地进行。1978年以来,在福州市以蕉柑、福桔和新会甜橙病树为毒源树,以柑桔实生健苗为指示植物,进行木虱传试验。结果在329株指示苗中,发病40株,发病率12.2%,潜育期短的半年,长的5年。对照指示苗72株均未见发病。1982~1984年,在饶平县以蕉柑病树为毒源树,以椪柑实生健苗为指示植物,共试验70株,发病33株,发病率47.1%,潜育期短的2个月,长的8个月。对照指示苗9株未见发病。木虱传染病苗的病状与毒源树的病状相同,均表现黄梢和叶片斑驳。获"毒"木虱的唾液腺和脂肪体的超薄切片样本在电镜下均观察到原核细胞微生物(称为类立次克体或类细菌)。唾液腺内的病原体分布在外皮层细胞,内皮层细胞和腺腔内。其菌体的形状大小和膜壁结构等特征均与毒源树及木虱传染病苗的筛管细胞内的相同,木虱获得和传递柑桔黄龙病病原的方式与蚜虫传播病毒中的持久性类型十分相似。 相似文献
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亚洲柑橘木虱DiaphorinacitriKuwayama是柑橘、脐橙等芸香科植物上的重要害虫,六斑月瓢虫Menochilussexmaculata(Fabricius)是我国南方地区常见的天敌昆虫。为了评价六斑月瓢虫对柑橘木虱的控害潜能,在室内条件下分别测定了六斑月瓢虫的1龄、4龄幼虫和成虫对柑橘木虱的低龄、高龄若虫和成虫的捕食功能反应、搜寻效应和自身密度干扰反应。结果表明,六斑月瓢虫的幼虫和成虫对柑橘木虱的若虫和成虫的捕食功能反应均能较好地拟合HollingⅡ型圆盘方程。其中六斑月瓢虫1龄幼虫对柑橘木虱低龄若虫的日最大捕食量为55.55头/d、高龄若虫为66.66头/d;六斑月瓢虫4龄幼虫对柑橘木虱低龄若虫的日最大捕食量为500头/d、高龄若虫为200头/d、成虫为200头/d;六斑月瓢虫成虫对柑橘木虱低龄若虫的日最大捕食量为333.33头/d、高龄若虫为250头/d、成虫为125头/d。六斑月瓢虫对柑橘木虱的搜寻效应随着猎物密度的增大而降低。由于捕食者自身密度的干扰,当柑橘木虱密度不变时随着六斑月瓢虫密度的增加,瓢虫单头捕食量减小、捕食效率降低、分摊竞争强度增大。本研究为田间应用... 相似文献
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应用Nested PCR技术检测柑桔木虱及其寄主九里香的柑桔黄龙病带菌率 总被引：28，自引：2，他引：28
应用PCR及Nested PCR技术检测柑桔木虱及其寄主九里香的结果表明:PCR只可检测最低2头带菌木虱,Nested PCR可检测到单个带菌木虱。100头带菌木虱中,单虫检出率为96％。检测田间重、中等、轻病的柑桔园内的木虱,其带菌率依次为87％、53％和21％。在病芦柑上饲菌不同天数的木虱均能检测出带菌,其饲菌时间最短为1d。城市九里香叶片及在其叶上取食的木虱单虫,均能用Nested PCR检测出病原。饲菌木虱接种九里香及芦柑健苗,在植株尚未表现症状时,常规PCR难检测出病原,但用Nested PCR则能检测到病原,说明九里香不仅是木虱的寄主,而且是黄龙病病原的隐症寄主。 相似文献
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ABSTRACT With diseases caused by vector-borne plant pathogens, acquisition and inoculation are two primary stages of the transmission, which can determine vector efficiency in spreading the pathogen. The present study was initiated to quantify acquisition and inoculation successes of 'Candidatus Liberibacter solanacearum', the etiological agent of zebra chip disease of potato, by its psyllid vector, Bactericera cockerelli (Hemiptera: Triozidae). Acquisition success was evaluated in relation to feeding site on the host plant as well as the acquisition access period. Inoculation success was evaluated in relation to vector number (1 and 4) on the plants. Acquisition success was influenced by the feeding site on the plant. The highest acquisition success occurred when insects had access to the whole plant. The results of the inoculation study indicated that the rate of successfully inoculated plants increased with the vector number. Plants inoculated with multiple psyllids had higher bacterial titer at the point of inoculation. Although disease incubation period was significantly shorter in plants inoculated with multiple psyllids, this effect was heterogeneous across experimental blocks, and was independent of pathogen quantity detected in the leaflets 3 days postinoculation. Disease progress was not affected by bacterial quantity injected or psyllid numbers. 相似文献
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Citrus huanglongbing (HLB or citrus greening), is a highly destructive disease that has been spreading in both Florida and Brazil. Its psyllid vector, Diaphorina citri Kuwayama, has spread to Texas and Mexico, thus threatening the future of citrus production elsewhere in mainland North America. Even though sensitive diagnostic methods have been developed for detection of the causal organisms, Candidatus Liberibacter spp., the pathogen cannot be detected consistently in plants until symptoms develop, presumably because of low titer and uneven distribution of the causal bacteria in nonsymptomatic tissues. In the present study, TaqMan based real-time quantitative polymerase chain reaction methodology was developed for detection of 'Ca. L. asiaticus' in D. citri. Over 1,200 samples of psyllid adults and nymphs, collected from various locations in Florida, from visually healthy and HLB symptomatic trees at different times of the year were analyzed to monitor the incidence and spread of HLB. The results showed that spread of 'Ca. L. asiaticus' in an area may be detected one to several years before the development of HLB symptoms in plants. The study suggests that discount garden centers and retail nurseries may have played a significant role in the widespread distribution of psyllids and plants carrying HLB pathogens in Florida. 相似文献
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The effects of soil temperature on infection of sugar-beet roots by the soil-borne fungus Polymyxa betae were investigated in controlled environments. Pre-germinated seeds were sown in pots of naturally infested soil and seedlings sampled at frequent intervals over a period of several weeks. Within the range 10-30°C, the optimum soil temperature for infection was c. 25°C; the time between sowing and the first detectable infection was shortest and the subsequent rate of infection most rapid at this temperature. No infection was observed over 80 days at 10°C.
Both root and shoot dry weight were reduced on plants growing in infested soil at 15, 20 and 25 C compared with those growing in uninfested soil. In general, root growth was more severely affected than shoot growth and the effects were most pronounced at 20°C. These results were confirmed in a subsequent experiment in which P. betae -infected root material was used as the inoculum. In addition to its role as the vector of beet necrotic yellow vein virus (the cause of Rhizomania disease), the significance of P. betae as a plant pathogen in its own right is discussed. 相似文献
Both root and shoot dry weight were reduced on plants growing in infested soil at 15, 20 and 25 C compared with those growing in uninfested soil. In general, root growth was more severely affected than shoot growth and the effects were most pronounced at 20°C. These results were confirmed in a subsequent experiment in which P. betae -infected root material was used as the inoculum. In addition to its role as the vector of beet necrotic yellow vein virus (the cause of Rhizomania disease), the significance of P. betae as a plant pathogen in its own right is discussed. 相似文献
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In an area of Nigeria where downy mildew of maize is present, histological assessment of maize seed revealed the presence of mycelium and oospores of Peronosclerospora sorghi in the kernels. Seed transmission of downy mildew of maize was demonstrated when grain purchased at local markets gave mean seedling infection rates of 12·3% (untreated seeds) and 10·0% (in metalaxyl-treated seeds) within 7 days of emergence, after storage in a desiccator for 30 days. When untreated seeds taken from nubbin ears of systemically infected plants from four states in southern Nigeria were planted at 9 days (17–22% moisture content) and 27 days (9–22% moisture content) after harvest, 20·0% infected seedlings resulted in both trials. Seeds from Borno state in northern Nigeria had 26·6% systemic seedling infection after 9 months of storage at 11% moisture content. When seeds harvested from maize plants inoculated with P. sorghi through silks were examined histologically, hyphae of P. sorghi were observed mostly in the scutellum of the embryo. Transmission of disease to seedlings was observed when the silk-inoculated seeds (9% moisture content) were planted in pots in a greenhouse; however, no disease transmission was observed when such seeds were planted in the field. The epidemiological significance of seed transmission is discussed with particular reference to survival of inoculum and development of epidemics. Also noteworthy is the overall significance of seed transmission in Nigeria, where the major source of seed is that saved by farmers from their grain crop, occasionally supplemented by seed bought from the local market. 相似文献
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广东新发生流行的水稻橙叶病的鉴定 总被引：4，自引：0，他引：4
1991~1992年广东茂名市的水稻约2万公顷发黄。用电光叶蝉Reclia dorsalis(Motsch)接种3叶龄稻苗,在平均气温28℃下,潜育期为8~36天;主要症状为病株矮,叶片竖直、橙黄至金黄色;部分病叶纵卷干枯;多数病苗早枯死。四环素液浸病稻根可明显延迟死亡。介体昆虫为电光叶蝉。而黑尾蝉Nephotettix cincticeps(Uhler)、二条(大斑)叶蝉N.apicalis(Motsch)和二点叶蝉N.virescence(Distant)以及虱Nilaparvata lugens(Stal)等均不传病。电光叶蝉最短获毒和最短传毒饲育期分别为<2min和<5min.期在室温25~30℃下,约为7~26天,保毒虫能终生传毒,但有间歇传病现象。在病叶脉韧皮筛管细胞毒叶蝉唾腺切片中均可见大量多形态的类菌原体,大小为75~639nm。据此认为本病与1980年云南十年代在东南亚报道的水稻橙叶病基本相同。 相似文献
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水稻紫鞘病是我国南方稻区生产上的一个新问题,发生面广,为害较重。经1978~1984年的研究,找到了引起紫鞘的病原茵是Acrocylindrium oryzae。带菌种子是本病的主要初次侵染来源;保存在干燥状态下的病稻草也有传病作用,稻田后期的某些虫、螨,可以传播病菌。紫鞘病病原菌的主要侵染方式是系统侵染。水稻孕穗期喷雾接菌,也能形成紫鞘,但注射法伤口接种时,大多形成虎纹斑烂鞘。因此,紫鞘是水稻叶鞘腐败病的又一种典型症状。病菌生长与产生孢子的适温为25~30℃。孕穗期接菌,其潜育期:30℃为1天,25~28℃为2天,23℃为3天,19℃为4天。 相似文献