宁波地区蔬菜主要病原线虫的分离和种类鉴定

对宁波14个主要蔬菜基地进行土壤和植株取样,通过形态学和分子生物学鉴定明确了宁波地区蔬菜主要病原线虫为南方根结线虫［Meloidogyne incognita (Kofoid & White)］和咖啡短体线虫［Pratylenchus coffeae (Zimmer mann)］。南方根结线虫主要分布在江北费市、宁海冠庄、宁波梅墟和镇海九龙湖,咖啡短体线虫分布在江北费市。南方根结线虫的寄主为番茄、黄瓜、豇豆和白菜,咖啡短体线虫的寄主为萝卜和大豆。     

江西省山药病原线虫种类鉴定及地理分布

为明确江西省山药病原线虫的种类及地理分布,对采自主产区的157份山药样品进行了线虫分离与形态学鉴定,并对主要病原线虫种类进行rDNA-ITS和28S的序列比对和种群系统进化分析。形态学和分子鉴定结果表明：山药病原线虫种类为咖啡短体线虫Pratylenchus coffeae和南方根结线虫Meloidogyne incognita。调查结果表明,咖啡短体线虫在江西省大部分山药产区广泛分布,是优势种群。吉安市永丰县和泰和县山药线虫危害最为严重,山药样品中线虫检出率分别为66.7%和88.9%。南方根结线虫在江西省山药产区不是优势种群,呈零星发生。此外,山药样品中存在两种线虫的单一种群侵染和复合种群侵染,分别占总样品数的87.1%和12.9%。综上,本研究明确了江西省山药主产区病原线虫的优势种是咖啡短体线虫,为江西省山药病原线虫的科学防控提供了有价值的参考依据。     

福建省花生根部寄生线虫种类鉴定

从福建省花生(Arachis hypogaea Linn.)根部及根际土壤中共分离鉴定出11种植物寄生线虫:肾状肾形线虫(Rotylenchulus reniformis)、咖啡短体线虫(Pratylenchus coffeae)、饰环矮化线虫(Tylenchorhynchus annula-tus)、装饰小环线虫(Criconemella ornata)、双宫螺旋线虫(Helicotylenchus dihystera)、食菌茎线虫(Ditylenchusmyceliophagus)、蘑菇滑刃线虫(Aphlenchoides composticola)、燕麦真滑刃线虫(Aphelenchus avenae)、广东杆垫刃线虫(Rhabdotylenchus guangdongensis)、丝尾垫刃线虫(Filenchus sp.)和根结线虫(Meloidogyne sp.)。其中肾状肾形线虫、咖啡短体线虫、装饰小环线虫和根结线虫为花生的重要寄生线虫。     

江苏进出口园林植物寄生线虫调查及检疫处理技术

1997－1998年，对南京口岸进口的荷兰、加拿大、美国、韩国、台湾和香港等国家和地区41批（次）园林植物检疫中，1次截获鳞球茎类线虫、19交截获咖啡短体线虫、草莓芽叶线虫、克鲁克剑线虫、毛刺尾线虫、南方根结线虫、花生根结线虫、北方根结线虫和其它根结线虫等，进口的园林植物中危险性疫情发生率高达34％。对江苏5个主要出口园林植物生长基地进行的植物寄生线虫种类调查，在59种经常性出口的园林植物中，发现27属植物寄生线虫，其中已鉴定出13种。对红花木莲苗上的南方根结线虫、牡丹苗上的腐烂茎线虫进行的检疫处理试验表明，用几种农药混配的处理液加热后处理植物的根部，可以有效地杀死这两种植物寄生线虫，保证货物安全出口。     

成都平原水旱轮作田常见根结线虫调查

调查四川省成都平原地区水旱轮作田根结线虫发生情况及种类分布,为水旱轮作田根结线虫的防治提供依据。对成都平原15个县(市、区)28个乡(镇)共159块水旱轮作田的土样进行根结线虫普遍率调查,利用线虫ITS通用引物和8对根结线虫特异性引物对其中检出率高的地区重新采集的土样进行根结线虫种类分子鉴定。结果表明,成都平原水旱轮作田根结线虫平均检出率为40.25%。重新采集的土样共鉴定出5种根结线虫:拟禾谷根结线虫Meloidogyne graminicola、花生根结线虫M. arenaria、南方根结线虫M. incognita、北方根结线虫M. hapla和爪哇根结线虫M. javanica,各线虫的检出率分别为40.91%、34.09%、13.64%、13.64%和2.27%,其中29.55%的样品由2种以上根结线虫混合侵染。拟禾谷根结线虫和花生根结线虫为该地区优势种群。     

甘肃陇南重要生产品种‘中梁27’抗条锈特点分析及其利用价值

运用比较形态学、同工酶和 mtDNA-PCR 对采自海南岛9个市县的南药根结线虫进行种类鉴定,结果发现有南方根结线虫、象耳豆根结线虫、爪哇根结线虫、花生根结线虫和西班牙根结线虫等5种根结线虫危害海南岛南药。5种根结线虫均能在海巴戟上寄生与危害,而南方根结线虫寄主非常广泛,可危害大多数调查的药用植物。     

海南岛南药根结线虫种类鉴定

运用比较形态学、同工酶和mtDNA-PCR对采自海南岛9个市县的南药根结线虫进行种类鉴定,结果发现有南方根结线虫、象耳豆根结线虫、爪哇根结线虫、花生根结线虫和西班牙根结线虫等5种根结线虫危害海南岛南药。5种根结线虫均能在海巴戟上寄生与危害,而南方根结线虫寄主非常广泛,可危害大多数调查的药用植物。     

根结线虫属的概要(续)

种的评论根结属线虫种的主要和次要特征的比较往往是非常困难的,颇有可能是归因于特征和形态量度的近似。泰晤士根结线虫 Melo-idogyne Thamesi 和赤特武根结线虫 M.C-hitwoodi 分别近似于花生根结线虫 M.aren-aria 和北方根结线虫 M.hapla.高弓根结线虫 M.acrita 和南方根结线虫瓦忒勒亚种 M.incognita wartelli 很难与南方根结线虫     

连作年限对番茄根围土壤根结线虫二龄幼虫与自由生活线虫数量的影响

 保护地连作是根结线虫为害严重的主要原因,为评估连作年限对根结线虫数量及其与土壤线虫数量关系,选择典型的不同连作时间的保护地(种植番茄),研究番茄生长期间根围土壤不同土层的根结线虫二龄幼虫(second-stage juveniles,J2)与自由生活线虫数量的动态变化。结果表明:根结线虫J2数量随连作年限增加而增多,0和5-year土壤中根结线虫数量少,平均根结线虫数为1.1和2.1条/100g干土,8、10和12-year土壤中根结线虫数量平均值分别为154.9、68.3和861.8条/100g干土;在0~30cm土层,根结线虫J2数量随土层加深而增加,主要分布在20~30cm土层。土壤自由生活线虫数量随土层的增加而增多,连作对自由生活线虫数量无显著影响。0和5-year土壤中根结线虫群体占土壤线虫总数的比例小,属稀有类群,在土壤线虫中处于稳定的群落结构状态。连作8、10和12-year的土壤中根结线虫J2为优势类群,土壤中自由生活线虫数量与根结线虫数量呈现相反的趋势,根结线虫J2占土壤线虫总数的比例增加,自由生活线虫与根结线虫J2数量的比值显著降低(P<0.05)。     

海南省蔬菜根结线虫发生种类与分布

2014年-2018年, 对海南省蔬菜根结线虫病害进行了田间随机采样调查和病原种类分子鉴定?结果显示, 蔬菜根结线虫病在海南18市县均有发生, 且大部分旱田连作地块病株率达到80%以上?进一步对采集的295份根结线虫样本种类进行了分子鉴定, 共鉴定出象耳豆根结线虫?南方根结线虫和爪哇根结线虫3种病原种?其中, 象耳豆根结线虫单一检出率达到62.37%, 南方根结线虫单一检出率为23.39%, 爪哇根结线虫的检出率仅为5.76%, 象耳豆根结线虫和南方根结线虫复合侵染检出率为8.47%?除五指山市样本以外, 海南其余17市县样本均检测到象耳豆根结线虫侵染为害?本研究显示象耳豆根结线虫为海南省蔬菜上的优势病原根结线虫种类, 该结果对指导品种布局?制定根结线虫病害的防治策略具有重要意义?     

珠海口岸进境咖啡生豆检疫情况分析

近年来,随着珠海口岸咖啡生豆进口量的增加,口岸截获咖啡果小蠹等有害生物的疫情也不断增加。本文通过对珠海地区进境咖啡生豆截获疫情分析,结合国外疫情发生情况,对我国口岸进境咖啡生豆检疫工作的重点进行探讨。     

Effect of cultural practices on the development of arabica coffee berry disease,caused by <Emphasis Type="Italic">Colletotrichum kahawae</Emphasis>

In the high altitude regions of Africa, coffee berry disease (CBD), caused by Colletotrichum kahawae, is the main constraint for arabica coffee (Coffea arabica) production. However, certain agricultural practices can reduce losses caused by the disease and thereby promote optimum production. On small family farms in Cameroon, mixed cropping with fruit trees, intercropping with food crops and maintenance pruning of coffee trees are very widespread agricultural practices that can affect CBD epidemics. Consequently, an epidemiological study was conducted to assess how cultural practices affected the disease in an arabica coffee smallholding in Cameroon. The disease was monitored on a weekly basis over four successive years (2002–2005) on coffee trees in diverse cultural situations. Cultural practices likely to reduce losses due to CBD were identified. The infection rate was significantly lower on coffee trees grown intensively than on coffee trees grown in the traditional manner. Coffee trees located under the shade of fruit trees were significantly less attacked than those located in full sunlight. In addition, berries on the leafless parts of branches, near the main trunk of the coffee tree, were less infected than those on leafy sections. These results show that maintenance pruning, removal of mummified berries, and mixed cropping with shade plants are cultural practices which create environmental conditions that limit CBD development.     

Effects of Meteorological Factors on the Development of Coffee Leaf Rust1

The development of coffee leaf rust (Hemileia vastatrix) was studied at Pindorama, SaTo Paulo State, Brazil, on a non-sprayed coffee plantation (cv. Mundo Novo). The disease intensity, evaluated by the proportion of rusted leaves, was lower during January and increased to reach its highest values in June-July. Stepwise regression analysis was used to identify the meteorological factors influencing coffee rust Rain and temperature explained most of the variation in the coffee leaf rust development.     

The potential protective value of ants in Northern Australian coffee plantations

Abstract

Native ants are the oldest example of biological control agents used in tropical tree crops. Unfortunately, intensification of agricultural practices has led to a simplification of habitat and subsequent loss of native ant biodiversity. This article describes research that evaluated the native and introduced ants present in the canopies of two Australian sun coffee plantations, their distribution pattern and their potential to limit pests. The presence in coffee plantations of a range of beneficial insects and parasites, plus the effect of ants, most notably Iridomyrmex suchieri Forel, may maintain potential pests at low levels in coffee plantations. These effects may be important for future biological control programs of coffee pests in Australia, although the sun coffee grown here does not harbor a large variety of canopy ant species.     

Role of rainfall in the development of coffee berry disease in Coffea arabica caused by Colletotrichum kahawae,in Cameroon

The development of coffee berry disease (CBD) epidemics (caused by Colletotrichum kahawae) in Cameroon was monitored over two successive years (2004 and 2005) on coffee trees protected from rainfall by transparent plastic sheets and on unprotected control trees. This work was done to assess how rain affected disease development when it did not fall directly onto the coffee trees and to determine the influence of primary inoculum on the severity of CBD. Weekly observations over the 2 years showed that there were 1·1% diseased berries on coffee trees completely protected from rainfall, compared with 45% diseased berries on unprotected coffee trees. Disease severity on unprotected trees during the 2 years of the experiment was estimated at 53% diseased berries, compared with 27% on trees only protected in the first year. These results confirmed rainfall as one of the key physical factors in the development of Arabica CBD. They also provided evidence of a subsequent effect of protecting coffee trees from rainfall in 2004 on the severity of CBD in 2005. This suggested some practices that might lead to very effective cultural control of CBD in regions where severe epidemics of the disease occur.     

Coffee bacterial diseases: a plethora of scientific opportunities

Coffee is a very important crop for several tropical countries across different continents. The diseases bacterial halo blight (BHB), bacterial leaf spot (BLS), bacterial leaf blight (BLB) and coffee leaf scorch (CLS), caused by the bacterial pathogens Pseudomonas syringae pv. garcae (Psgc), P. syringae pv. tabaci (Psta), Pseudomonas cichorii (Pch) and Xylella fastidiosa subsp. pauca (Xfp), respectively, cause significant reductions in coffee production, although other minor bacterial diseases have also been reported in some countries. Little research progress has been made on aspects that are relevant for control and management of these diseases. In all cases, there is an urgent need to develop rapid and more reliable methods for early detection of the pathogens in order to minimize their negative impact on coffee production. Because of the high rate of intra- and intersubspecific recombination occurring in X. fastidiosa, a permanent revision of the detection methods is necessary. Greater efforts should be made to understand the genetic and virulence diversity of Psgc, Psta and Pch populations. Early studies reported the identification of potential sources of resistance against Psgc and Psta, but, to date, no resistance gene has been isolated. Little effort has been made to understand the biology and molecular mechanisms underlying the interaction between Coffea spp. and these pathogenic bacteria. This review discusses the recent progress on the molecular mechanisms used by these bacteria to cause diseases on other plant species, in order to provide a guideline for the establishment of future research programmes.     

Characterization of a New Subgroup of Rhizoctonia solani Anastomosis Group 1 (AG-1-ID), Causal Agent of a Necrotic Leaf Spot on Coffee

ABSTRACT A new foliar disease on coffee leaves was observed in Mindanao, Philippines, in 1996. The symptoms appeared as large circular or irregularly shaped necrotic areas with small circular necrotic spots (1 mm or less in diameter) usually found around the periphery of the large necrotic areas. Rhizoctonia solani was consistently isolated from these diseased coffee leaves. Isolates obtained were multinucleate (3 to 12 nuclei per hyphal cell), had an optimum temperature for hyphal growth at 25 degrees C, prototrophic for thiamine, and anastomosed with tester isolates belonging to R. solani anastomosis group 1 (AG-1). Mature cultures on potato dextrose agar (PDA) were light to dark brown. Sclerotia, light brown to brown, were formed on the surface of PDA and covered the whole mature colony culture. Individual sclerotia often aggregated into large clumps (3 to 8 mm in diameter) and their color was brown to dark brown. In pathogenicity tests, isolates from coffee caused necrotic symptoms on coffee leaves, whereas isolates of AG-1-IA (not isolated from coffee), 1-IB, and 1-IC did not. The results of analyses of restriction fragment length polymorphism of ribosomal DNA internal transcribed spacer, random amplified polymorphism DNA, and fatty acid profiles showed that R. solani isolates from coffee are a population of AG-1 different from AG-1-IA, 1-IB, and 1-IC. These results suggest that R. solani isolates from coffee represent a new subgroup distinct from AG-1-IA, 1-IB, and 1-IC. A new subgroup ID (AG-1-ID) is proposed.     

Effects of crop management patterns on coffee rust epidemics

The effects of crop management patterns on coffee rust epidemics, caused by Hemileia vastatrix , are not well documented despite large amounts of data acquired in the field on epidemics, and much modelling work done on this disease. One main reason for this gap between epidemiological knowledge and understanding for management resides in the lack of links between many studies and actual production situations in the field. Coffee rust epidemics are based on a seemingly simple infection cycle, but develop polycyclic epidemics in a season and polyetic epidemics over successive seasons. These higher-level processes involve a very large number of environmental variables and, as in any system involving a perennial crop, the physiology of the coffee crop and how it affects crop yield. Crop management is therefore expected to have large effects on coffee rust epidemics because of its immediate effect on the infection cycle, but also because of its cumulative effect on ongoing and successive epidemics. Quantitative examples taken from a survey conducted in Honduras illustrate how crop management, different combinations of shade, coffee tree density, fertilization and pruning may strongly influence coffee rust epidemics through effects on microclimate and plant physiology which, in turn, influence the life cycle of the fungus. We suggest there is a need for novel coffee rust management systems which fully integrate crop management patterns in order to manage the disease in a sustainable way.     

Integrated pest management of coffee for small-scale farmers in East Africa: needs and limitations

Coffee in East Africa (Kenya, Tanzania and Uganda) is an important cash and export crop for small-scale farmers. The crop suffers heavy yield losses due to damage caused by a wide range of indigenous pests (insects, diseases, nematodes and weeds). Current recommended pest control measures include a combination of cultural, resistant/tolerant cultivars and the use of broad spectrum chemical pesticides. Chemical pesticides are far more popular at the farm level than any of the other recommended pest control measures. Coffee pest control strategies are often aimed at individual pests with little consideration of the implications for the total coffee pest complex and its agro-ecosystem. This unilateral approach has resulted in increased pest pressure on coffee and some of its companion crops, outbreak of new pests of coffee, development of pest strains resistant to the cheap and commonly available chemical pesticides, increased environmental problems, increased health risks to man and livestock and an overall increase in the costs of coffee production, thus forcing many farmers to neglect their coffee plantations. Measures to alleviate the above problems, particularly the high production costs, are needed to improve coffee production and increase the cash return to the small-scale farmer. Integrated pest management (IPM) offers the best prospects for solving the above problems. However, lack of national IPM policies, poor extension systems, inefficient research-extension-farmer linkage and the lack of a holistic approach will delay the development and implementation of appropriate, acceptable and sustainable IPM practices.