Host Status of Alfalfa Cultivars and Germ Plasms to Meloidogyne chitwoodi Race 2 and Reactions of Selected Cultivars to M. chitwoodi and M. hapla Infection

Abstract The results of experiments, performed in The Netherlands during the last decade, on the host range of Meloidogyne chitwoodi and M. fallax are presented and discussed. Opinions are expressed on the host status of the tested plants and the phytosanitary status of the commercial product (defined as that part of the plant that enters trade) separately, as interest for both categories may differ. Information for each category is given for a variety of plants such as vegetables, arable crops, flowering bulbs and plants, and ornamental plants and trees. Data obtained from glasshouse experiments are given in a separate table. Many plants are a good host for one or both nematode species, and the commercial product, such as some bulbs and potatoes, might form a phytosanitary risk as a carrier of the juveniles inside the product, this risk being increased when that commercial product has roots.

Download Full-text

A New Pathotype of Meloidogyne chitwoodi Race 1 from Washington State

Plant Disease ◽

10.1094/pdis-91-8-1051a ◽

2007 ◽

Vol 91 (8) ◽

pp. 1051-1051 ◽

Cited By ~ 6

Author(s):

H. Mojtahedi ◽

C. R. Brown ◽

E. Riga ◽

L. H. Zhang

Keyword(s):

Solanum Tuberosum L ◽

Initial Population ◽

Host Race ◽

Reproductive Factor ◽

Wild Potato Species ◽

Meloidogyne Chitwoodi ◽

Breeding Lines ◽

Resistant Lines ◽

Race 1 ◽

Race 2

Meloidogyne chitwoodi Golden et al. is a serious pest of potato (Solanum tuberosum L.), and is widespread in the Pacific Northwest United States. M. chitwoodi is currently reported to consist of two host races and one pathotype (2,3) that are not distinguished morphologically. Host race 1 reproduces on Chantenay carrot but not on Thor alfalfa and host race 2 reproduces on alfalfa but not on carrot. Both races fail to reproduce on roots of S. bulbocastanum, a wild potato species used as a source of resistance in our breeding program (1). The resistance to race 1 in S. bulbocastanum is attributed to Rmc1(blb) gene. Pathotype 1 of race 2 breaks resistance and reproduces on S. bulbocastanum (2). We have tested resistant breeding lines repeatedly in Prosser, WA field plots infested with MC race 1 and harvested tubers free from M. chitwoodi damage. In 2004 however, tubers of some resistant lines were damaged by the M. chitwoodi population that did not cause damage in the past. Populations of M. chitwoodi were established on tomato by adding peels obtained from the infected tubers of resistant lines. The reproductive factor, final number of eggs ÷ initial inoculum, of the new population was determined on five replications of 3-week-old Chantenay carrot and Thor alfalfa. Five thousand eggs were extracted from nematode cultures reared on tomatoes and then were added around the root system of the test plants. The plants were maintained in the greenhouse for 55 days before the nematode eggs were extracted and RF (reproductive factor = final/initial population) values determined. Like the MC race 1, new populations reproduced on Chantenay carrot (RF > 1) but failed to reproduce on Thor alfalfa (RF < 0.1). Unlike MC race 1, the new populations reproduced on roots of all breeding lines that carried Rmc1(blb) gene (RF > 1). These results suggest that the selected population of M. chitwoodi in the Prosser site is a new pathotype, which is designated pathotype 1 of MC race 1. References: (1) C. R. Brown et al. Am. J. Potato Res. 83:1, 2006. (2) H. Mojtahedi et al. J. Nematol. 30:506, 1998. (3) G. S. Santo et al. Plant Dis. 69:361, 1985.

Download Full-text

Host status of progenies of yellow passion fruit to Meloidogyne incognita race 2

Cropp Breeding and Applied Biotechnology ◽

10.1590/1984-70332016v16n2n23 ◽

2016 ◽

Vol 16 (2) ◽

pp. 153-157

Author(s):

Roxana Stefane Mendes Nascimento ◽

Everaldo Antônio Lopes ◽

Carlos Eduardo Magalhães dos Santos ◽

Viviane Manuela Bernardes Silva Magalhães ◽

José Avelino Cardoso

Keyword(s):

Meloidogyne Incognita ◽

Passion Fruit ◽

Host Status ◽

Race 2 ◽

Yellow Passion Fruit

Download Full-text

Host status of six major weeds to Meloidogyne chitwoodi and Pratylenchus penetrans, including a preliminary field survey concerning other weeds

Nematology ◽

10.1163/156854106778877839 ◽

2006 ◽

Vol 8 (5) ◽

pp. 647-657 ◽

Cited By ~ 9

Author(s):

Vhukile Kutywayo ◽

Thomas H. Been

Keyword(s):

Weed Control ◽

Field Survey ◽

Point Sources ◽

Cirsium Arvense ◽

Multiplication Rate ◽

Pratylenchus Penetrans ◽

Population Densities ◽

Meloidogyne Chitwoodi ◽

Echinochloa Crusgalli ◽

Host Status

Abstract A glasshouse experiment was carried out to investigate the host status of six important weeds in intensive agricultural cropping systems to Meloidogyne chitwoodi and Pratylenchus penetrans. Senecio vulgaris L., Capsella bursa-pastoris (L.) Medic. and Solanum nigrum L. were hosts of M. chitwoodi with reproduction factors of 2.5, 2.6 and 7.8, respectively. Echinochloa crusgalli (L.) Beauv. and Stellaria media (L.) Vill. were non-hosts for M. chitwoodi as no galls or eggs were observed. Galinsoga parviflora Cav. is considered a poor host with one out of eight plants producing an egg mass, but maintaining significantly higher population densities in the soil than were recorded in the fallow pots. Echinochloa crusgalli, S. nigrum and S. vulgaris were hosts of P. penetrans with multiplication factors of 1.6, 1.82 and 4.29, respectively. The multiplication rate of P. penetrans on S. vulgaris was similar to the one recorded on maize, the susceptible control. Galinsoga parviflora, S. media and C. bursa-pastoris were non-hosts as no specimen of the target nematode was found in the roots. After 16 weeks, only 1.22 and 0.08% of the original population was still alive for P. penetrans and M. chitwoodi, respectively. In conjunction with the pot experiment, a field survey was conducted at two sites, each of which was known to be highly infested with either M. chitwoodi or P. penetrans. Based on the survey results, Cirsium arvense Scop. and C. bursa-pastoris can also be considered to be hosts of M. chitwoodi, whilst Cirsium arvense, Chenopodium album L. and Polygonum convolvulus L. were recorded as hosts of P. penetrans. These results call attention to the possibility of weeds acting as carriers and point sources of possible high population densities of plant-parasitic nematodes. It emphasises the importance of adequate weed control in an integrated programme for management of M. chitwoodi and P. penetrans and the possible failure of the successful use of non-host crops and fallow in crop rotations when weed control is inadequate.

Download Full-text

Variation in host status of Brassica spp. for isolates of the Columbia root-knot nematode, Meloidogyne chitwoodi, and potential mechanisms

Nematology ◽

10.1163/156854108785787316 ◽

2008 ◽

Vol 10 (5) ◽

pp. 767-775 ◽

Cited By ~ 3

Author(s):

J.G. (Hans) van der Beek ◽

Didier Mugniéry

Keyword(s):

Quantitative Resistance ◽

Petri Dish ◽

Hypersensitive Reaction ◽

F1 Hybrids ◽

Root Knot Nematode ◽

Meloidogyne Chitwoodi ◽

Large Variability ◽

Brassica Spp ◽

Host Status ◽

High Level

Abstract Interaction of the Columbia root-knot nematode, Meloidogyne chitwoodi, with Brassica spp. was studied in pot and in Petri dish experiments for 11 nematode isolates and three F1 hybrids of cauliflower, broccoli and rapeseed. In the pot experiment, the host status of the different Brassica hybrids varied greatly (average of 4-45 egg-masses). The isolate-by-cultivar interaction effect was significant but depended only on three exceptions to the generally equal patterns for all isolates. In the Petri dish experiment, this large variation in aggressiveness was confirmed. Cauliflower, as a host for M. chitwoodi, is less favourable than rapeseed, and rapeseed is less favourable than broccoli. Several mechanisms are involved in the host-parasite interaction: limitation in penetration, in juvenile development, and in female-male ratio, each one acting with a high level of specificity to the isolates tested. No hypersensitive reaction was observed. In view of this quantitative resistance reaction, the species M. chitwoodi expresses an extremely large variability in terms of aggressiveness.

Download Full-text

Host-status and host-sensitivity of potato cultivars ‘BP1’ and ‘Buffelspoort’ to Meloidogyne javanica and Meloidogyne incognita race 2 under greenhouse and micro plot conditions

Acta Horticulturae ◽

10.17660/actahortic.2020.1269.16 ◽

2020 ◽

pp. 119-128

Author(s):

N.K. Mulandana ◽

K.M. Pofu ◽

M.M. Slabbert

Keyword(s):

Meloidogyne Incognita ◽

Meloidogyne Javanica ◽

Potato Cultivars ◽

Host Status ◽

Race 2

Download Full-text

Campus Diversity: Implementing the Town Hall Approach for Racial and Cultural Understanding at a Predominantly White University

NASPA Journal ◽

10.2202/0027-6014.1191 ◽

2002 ◽

Vol 40 (1) ◽

Author(s):

Celina Valentina Echols ◽

Young Suk Hwang ◽

Connie Nobles

Keyword(s):

Predominantly White ◽

Campus Climate ◽

Cross Cultural ◽

Town Hall ◽

Campus Diversity ◽

Predominantly White University ◽

Attitudes And Knowledge ◽

Race 2 ◽

The Town ◽

Cultural Interactions

This paper uses students responses from the dialogues of a town hall meeting to examine the beliefs, attitudes, and knowledge about racial and cultural diversity at a mid-size, predominantly white university in Louisiana. The four major themes that emerged from this experience were: (1) perceptions about race, (2) stereotypical beliefs about cross-cultural interactions, (3) uncomfortable campus climate, and (4) disequilibria associated with prejudicial teaching by parents. Implications and recommendations for increasing positive cross-cultural interactions among members of the campus community are discussed.

Download Full-text

Host Suitability Index for Polyphagous Tephritid Fruit Flies

Journal of Economic Entomology ◽

10.1093/jee/toab035 ◽

2021 ◽

Author(s):

Peter A Follett ◽

Fay E M Haynes ◽

Bernard C Dominiak

Keyword(s):

Fruit Fly ◽

Fruit Production ◽

General Purpose ◽

Fruit Flies ◽

Host Suitability ◽

Bactrocera Dorsalis ◽

Infestation Rate ◽

Suitability Index ◽

Host Status ◽

Tephritid Fruit Flies

Abstract Tephritid fruit flies are major economic pests for fruit production and are an impediment to international trade. Different host fruits are known to vary in their suitability for fruit flies to complete their life cycle. Currently, international regulatory standards that define the likely legal host status for tephritid fruit flies categorize fruits as a natural host, a conditional host, or a nonhost. For those fruits that are natural or conditional hosts, infestation rate can vary as a spectrum ranging from highly attractive fruits supporting large numbers of fruit flies to very poor hosts supporting low numbers. Here, we propose a Host Suitability Index (HSI), which divides the host status of natural and conditional hosts into five categories based on the log infestation rate (number of flies per kilogram of fruit) ranging from very poor (<0.1), poor (0.1–1.0), moderately good (1.0–10.0), good (10–100), and very good (>100). Infestation rates may be determined by field sampling or cage infestation studies. We illustrate the concept of this index using 21 papers that examine the host status of fruits in five species of polyphagous fruit flies in the Pacific region: Bactrocera tryoni Froggatt, Bactrocera dorsalis (Hendel), Bactrocera latifrons (Hendel), Zeugodacus cucurbitae (Coquillett), and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). This general-purpose index may be useful in developing systems approaches that rely on poor host status, for determining surveillance and detection protocols for potential incursions, and to guide the appropriate regulatory response during fruit fly outbreaks.

Download Full-text

DISTRIBUTION AND RACE COMPOSITION OF DOWNY MILDEW (Plasmopara halstedii (Farl.) Berl. and de Toni) IN BULGARIA / EXTENSION Y RAZAS DEL MILDIU (Plasmopara halstedii (Farl.) Berl. y de Toni) EN BULGARIA / ÉTENDUE ET RACES DE LA ROUILLE (Plasmopara halstedii (Farl.) Berl. and de Toni) EN BULGARIE

Helia ◽

10.1515/helia.2000.23.33.25 ◽

2000 ◽

Vol 23 (33) ◽

pp. 25-32

Author(s):

P.S. Shindrova

Keyword(s):

Downy Mildew ◽

Resistance Gene ◽

The Other ◽

Plasmopara Halstedii ◽

North West ◽

North East ◽

Race 1 ◽

Race 2 ◽

Production Areas ◽

Number Of Authors

SUMMARY Downy mildew caused by the fungus Plasmopara halstedii is the main disease on sunflower in Bulgaria. In recent years a number of authors have reported the occurrence of new more virulent races of the pathogen. According to other authors these races demonstrate resistance to the fungicides used up to now. This fact is rather alarming and imposes the necessity of annual researches with the aim of following the changes in the downy mildew race variability. In the period 1995-1997 downy mildew isolates were collected from the following locations: Bourgas, Boyanovo, Karnobat, Ognyanovo, Selanovtsi, Kroushari, Lovech, Koubrat, Brashlyan, Sitovo, Tervel, Targovishte, IWS “Dobroudja” and Dobrich. The samples were assessed for virulence on a set of sunflower differential - lines under greenhouse conditions. The obtained results do not reveal a great race variability of downy mildew population in Bulgaria. In the period of study two races of the pathogen were identified: race 1 which infects the differential lines without genes for resistance to the pathogen. It is distributed in all sunflower production areas of the country. The other one is race 2. It is of limited distribution and has been registered in individual fields of north-east and north-west Bulgaria. It attacks the differential lines carrying the resistance gene Pl-1.

Download Full-text