Climatic elimination of mosaic spread in lettuce seed crops in the Swan Hill region of the Murray Valley

1962 ◽  
Vol 2 (4) ◽  
pp. 16 ◽  
Author(s):  
LL Stubbs ◽  
GT O'Loughlin
Keyword(s):  
Aphis Gossypii ◽  
Mosaic Disease ◽  
Macrosiphum Euphorbiae ◽  
Lettuce Seed ◽  
Trapping Period ◽  
Hill Region ◽  
Aphid Vectors ◽  
Average Relative Humidity ◽  
Seed Crops

The elimination of lettuce mosaic disease, formerly an economical important problem of market lettuce in Victoria, has been achieved by the .we of seed produced in the vicinity of Swan Hill. During the last quarter of 1960, trapping records of the incidence of four species of aphid vectors for lettuce mosaic virus were obtained from two localities in that area, and in Melbourne. The aphids Myzus persicae (July.), Macrosiphum euphorbiae (Thos.), Aphis gossypii Glover and Hyperomyzus lactucae (L.), were caught throughout the trapping period in Melbourne, September to December but not during November and December at the Swan Hill sites. The absence of aphids during most of the growing season for lettuce seed crops, explains the progressive reduction of seedborne mosaic which has occurred in varieties grown for several consecutive seasons in the Swan Hill region. During the trapping period more days with temperatures above 90�F occurred at Swan Hill than Melbourne, and long term records over the same period showed a similar trend. Differences in average relative humidity between the two localities were more significant. Swan Hill records (13 years) showed a progressive and pronounced reduction in humidity during the months September-December, whereas Melbourne records (30 years) were higher and practical constant.

scholarly journals Can Winged Aphid Abundance Be a Predictor of Cucurbit Aphid-Borne Yellows Virus Epidemics in Melon Crop?

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 911
Author(s):  
Alexandra Schoeny ◽  
Loup Rimbaud ◽  
Patrick Gognalons ◽  
Grégory Girardot ◽  
Pauline Millot ◽  
...  
Keyword(s):  
Field Experiments ◽  
Aphis Gossypii ◽  
Logistic Models ◽  
Aphid Species ◽  
Control Measures ◽  
Macrosiphum Euphorbiae ◽  
Vegetable Crops ◽  
Aphid Vectors ◽  
The Relationship ◽  
Winged Aphid

Aphid-borne viruses are frequent yield-limiting pathogens in open field vegetable crops. In the absence of curative methods, virus control relies exclusively on measures limiting virus introduction and spread. The efficiency of control measures may greatly benefit from an accurate knowledge of epidemic drivers, in particular those linked with aphid vectors. Field experiments were conducted in southeastern France between 2010 and 2019 to investigate the relationship between the epidemics of cucurbit aphid-borne yellows virus (CABYV) and aphid vector abundance. Winged aphids visiting melon crops were sampled daily to assess the abundance of CABYV vectors (Aphis gossypii, Macrosiphum euphorbiae and Myzus persicae) and CABYV was monitored weekly by DAS-ELISA. Epidemic temporal progress curves were successfully described by logistic models. A systematic search for correlations was undertaken between virus variables including parameters µ (inflection point of the logistic curve) and γ (maximum incidence) and aphid variables computed by aggregating abundances on periods relative either to the planting date, or to the epidemic peak. The abundance of A. gossypii during the first two weeks after planting was found to be a good predictor of CABYV dynamics, suggesting that an early control of this aphid species could mitigate the onset and progress of CABYV epidemics in melon crops.

THE ROLE OF INSECTS IN THE SPREAD OF CUCUMBER MOSAIC VIRUS

1964 ◽  
Vol 44 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. J. McClanahan ◽  
G. E. Guyer
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Small Proportion ◽  
Aphis Gossypii ◽  
Macrosiphum Euphorbiae ◽  
Asclepias Syriaca ◽  
Melanoplus Differentialis ◽  
Aphis Gossypii Glover ◽  
Echinocystis Lobata

Entomological aspects of the epidemiology of cucumber mosaic virus (CMV) were studied in Michigan. Myzus persicae (Sulzer) and Aphis gossypii Glover were efficient vectors of CMV between various hosts in the laboratory. Macrosiphum euphorbiae (Thomas) transmitted CMV between cucumber and Echinocystis lobata (Michx.) T. & G. Myzocallis asclepiadis (Monell) was shown to be a new vector of CMV between Asclepias syriaca L. Neither Melanoplus differentialis (Thomas) nor Acalymma vittata (Fabricius) transmitted the virus in limited trials.There was a small proportion of cucumber plants infected early in July, when alate M. persicae were present. In August the incidence of infection rose rapidly after a period of activity of alate A. gossypii. Alate aphids were trapped in yellow water pans situated in and around cucumbers. Seven known vectors of CMV were caught.

scholarly journals Evaluación de barreras vegetales en el manejo integrado de la mancha anular del papayo (PRSV-P) en Michoacán, México

2008 ◽  
Vol 34 (4) ◽  
pp. 307-312 ◽  
Author(s):  
Patricia Rivas-Valencia ◽  
Gustavo Mora-Aguilera ◽  
Daniel Téliz-Ortiz ◽  
Antonio Mora-Aguilera
Keyword(s):  
Aphis Gossypii ◽  
Macrosiphum Euphorbiae ◽  
Hibiscus Sabdariffa ◽  
La Mancha

El efecto de barreras vegetales como componente de un programa de manejo integrado (MI), se validó y adaptó en 1999 en Michoacán, México, para controlar la Mancha Anular del Papayo, enfermedad causada por el Papaya ringspot potyvirus type-P (PRSV-P). Se estableció un experimento en parcelas divididas con dos factores experimentales: barreras vegetales (Hibiscus sabdariffa), y componentes de MI: MI sin aspersión de citrolina (1.5%) (MI-A), MI sin eliminación de plantas con síntomas iniciales de virosis antes de floración (MI-D) y MI. Las barreras vegetales sembradas 20 días antes del trasplante del papayo y el desplante retrasaron en 19 días el inicio del progreso de epidemias en el MI lo que resultó en una mayor producción (14.2%) que el resto de tratamientos, aunque fue superado por MI-A en vigor (4% en diámetro de tallo). La citrolina fue fitotóxica, disminuyó el vigor de plantas (5.3%) y no limitó significativamente el desarrollo de la enfermedad ya que la intensidad de las epidemias (X0 = 47días, Yf = 84% y ABCPE = 3220% días) fue similar al testigo. El uso de barreras vegetales por si sola aparentemente no es suficiente para la reducción de la incidencia y dispersión de la enfermedad. Los áfidos más abundantes, con reconocida capacidad transmisora del PRSV-P, fueron Aphis gossypii, A. nerii, A. spiraecola y Macrosiphum euphorbiae, los cuales representaron aproximadamente el 13% del total de áfidos capturados.

scholarly journals Long-Term Seedfall, Establishment, Survival, and Growth of Natural and Planted Ponderosa Pine in the Colorado Front Range

2006 ◽  
Vol 21 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Wayne D. Shepperd ◽  
Carleton B. Edminster ◽  
Stephen A. Mata
Keyword(s):  
Ponderosa Pine ◽  
Basal Area ◽  
Colorado Front Range ◽  
Initial Growth ◽  
Front Range ◽  
Natural Seedling ◽  
Survival And Growth ◽  
Seed Crops ◽  
Better Than

Abstract Seedfall, natural regeneration establishment, and growth of planted seedlings was observed from 1981 to 2001 under shelterwood and seedtree overstories in a replicated study in ponderosa pine in the Manitou Experimental Forest in the Colorado Front Range. Good seed crops were produced only every 4 to 6 years, with almost no viable seed produced in intervening years. With seed predation, only 14% of total seedfall was available for germination. Shelterwood overstories containing between 6 and 14 m2 ha−1 stem basal area over scarified seedbeds provided optimal conditions for natural seedling establishment. Survival and growth of planted seedlings was much better than that of natural seedlings. However, poor survival and slow initial growth may require many years to establish a fully stocked forest of natural seedlings.

scholarly journals Resistência de genótipos de batata, Solanum spp., a afídeos (Homoptera: Aphididae) e influência sobre parasitóides

1999 ◽  
Vol 28 (4) ◽  
pp. 721-728 ◽  
Author(s):  
Fernando M. Lara ◽  
Edimar A. da Silva ◽  
Arlindo L. Boiça Junior
Keyword(s):  
Myzus Persicae ◽  
Aphis Gossypii ◽  
Macrosiphum Euphorbiae ◽  
Aphidius Ervi ◽  
Aphis Gossypii Glover ◽  
Solanum Spp

Avaliou-se a resistência de genótipos de batata aos afídeos Myzus persicae (Sulz.), Macrosiphum euphorbiae (Thomas) e Aphis gossypii (Glover), e a influência desses genótipos sobre parasitóides, em dois ensaios em plantios de inverno (1996 e 1997), em condições de campo, em Jaboticabal, SP. Os genótipos plantados no primeiro ano foram: Achat, Baronesa, Bintje, BR-2, Contenda, Monalisa, N 140-201 e NYL 235-4, distribuídos em quatro blocos ao acaso. Dois levantamentos foram efetuados, aos 70 e 85 dias após o plantio, avaliando-se o número de pulgões/folha e pulgões parasitados, nos terços superior, médio e inferior da planta. Em 1997 plantaram-se os mesmos genótipos, excetuando-se o N 140-201, com levantamentos aos 72 e 80 dias. O genótipo NYL 235-4 mostrou-se suscetível a M. euphorbiae, sob infestações médias de 2,90 (1996) e 1,19 pulgões/folha (1997); dentre as cultivares comerciais, Baronesa foi a menos atacada por M. persicae (0,12 e 0,10 pulgões/folha em 1996 e 1997), enquanto BR-2 foi bem suscetível (1,10 e 0,66 pulgões/folha). Os afídeos ocorreram em maior população nas partes média e inferior das plantas; maior número de pulgões mumificados por Aphidius ervi Hal. e Diaretiella rapae (McIntosh), com parasitismo variando de 15 a 36%, foi observado em NYL 235-4, que foi o genótipo mais infestado pelos afídeos.

A downflow hanging sponge (DHS) reactor for faecal coliform removal from an upflow anaerobic sludge blanket (UASB) effluent

2015 ◽  
Vol 72 (11) ◽  
pp. 2034-2044 ◽  
Author(s):  
Rosa Elena Yaya Beas ◽  
Katarzyna Kujawa-Roeleveld ◽  
Jules B. van Lier ◽  
Grietje Zeeman
Keyword(s):  
Oxygen Demand ◽  
Faecal Coliform ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Removal Capacity ◽  
Seed Crops ◽  
Anaerobic Sludge Blanket

This research was conducted to study the faecal coliforms removal capacity of downflow hanging sponge (DHS) reactors as a post-treatment for an upflow anaerobic sludge blanket (UASB) reactor. Three long-term continuous laboratory-scale DHS reactors, i.e. a reactor with cube type sponges without recirculation, a similar one with recirculation and a reactor with curtain type sponges, were studied. The porosities of the applied medium were 91%, 87% and 47% respectively. The organic loading rates were 0.86 kgCOD m−3 d−1, 0.53 kgCOD m−3 d−1 and 0.24 kgCOD m−3 d−1 correspondingly at hydraulic loading rates of 1.92 m3 m−2 d−1, 2.97 m3 m−2 d−1 and 1.32 m3 m−2 d−1, respectively (COD: chemical oxygen demand). The corresponding averages for faecal coliform removal were 99.997%, 99.919% and 92.121% respectively. The 1989 WHO guidelines standards, in terms of faecal coliform content for unrestricted irrigation (category A), was achieved with the effluent of the cube type DHS (G1) without recirculation. Restricted irrigation, category B and C, is assigned to the effluent of the cube type with recirculation and the curtain type, respectively. Particularly for organic compounds, the effluent of evaluated DHS reactors complies with USEPA standards for irrigation of so called non-food crops like pasture for milking animals, fodder, fibre, and seed crops.

scholarly journals Diversity of aphid pests on the crops in Kanchanpur district, Nepal

2020 ◽  
Vol 31 (1) ◽  
pp. 95-106
Author(s):  
Mahadev Bista
Keyword(s):  
Acyrthosiphon Pisum ◽  
Rhopalosiphum Padi ◽  
Aphis Gossypii ◽  
Aphis Fabae ◽  
Macrosiphum Euphorbiae ◽  
Agricultural Crops ◽  
Rhopalosiphum Maidis ◽  
Aphis Craccivora Koch ◽  
Macrosiphum Rosae ◽  
Different Parts

A survey was conducted to explore the aphid pests’ diversity in Kanchanpur district, far-western, Nepal from April 2018 to March 2019. A total of 15 aphid pests were collected and identified, viz. Acyrthosiphon pisum (Harris), Aphis craccivora (Koch), Aphis gossypii (Glover), Aphis fabae (Scopoli), Aphis nerii Boyer de Fonscolombe, Brevicoryne brassicae (Linnaeus), Lipaphis erysmi (Kaltenbach), Macrosiphum euphorbiae (Thomas), Macrosiphum rosae (Linnaeus), Myzus persicae (Sulzer), Rhopalosiphum maidis (Fitch), Rhopalosiphum padi (Linnaeus), Rhopalosiphum rufiadominale (Sasaki), Uroleucon compositae (Theobald), and the guava aphid. Exploration of aphid pests showed that they caused serious damages to agricultural crops by attacking different parts of plants.

scholarly journals 069 Preservation of Lettuce Seed for 30 Years: Cryopreservation Retarded Deterioration

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 400D-400
Author(s):  
P.C. Stanwood ◽  
L. Wheeler ◽  
L.E. Towill
Keyword(s):  
Storage Temperature ◽  
Seed Vigor ◽  
Lettuce Seed ◽  
Seed Moisture Content ◽  
Fresh Weight Basis ◽  
C Storage ◽  
Seed Moisture ◽  
Nitrogen Vapor ◽  
Long Term Preservation

Long-term preservation of seed germplasm is a high agricultural priority. It assures that genetic diversity will be available for future generations for continued plant improvement. This experiment reports on the affect that storage temperature had on the viability of 65 selections of lettuce seed stored for 30 years. The average seed moisture content was 5.5% ± 0.5% (fresh weight basis). Fresh seed samples were placed at 5 °C storage in 1969. In 1975 they were then transferred to -18 °C storage. Viability remained at 98% ± 5% for the first 14 years of 5 /-18 °C storage, then viability declined. At 17 years storage, the average viability had dropped to 75% and continued to drop at about 4%/year. At the 17-year mark, individual samples were split, one-half remained at -18 °C the other half was placed under liquid nitrogen vapor (lnv) conditions (about -150 to -190 °C). The -18 °C stored samples continued to deteriorate to 14% viability at the 30 year test period (1999). The samples placed in lnv did not decrease further in viability and remained at 75% viability at the 30-year mark. Seed vigor was reduced in the -18 °C stored seeds that were still viable. The lnv-preserved samples were significantly more vigorous. It is clear from this experiment that lnv preservation was significantly superior to -18 °C storage and, in fact, stopped or significantly reduced the rate of viability loss in samples that are rapidly deteriorating.

scholarly journals Studying the genetic basis of masting

2021 ◽  
Vol 376 (1839) ◽  
Author(s):  
Akiko Satake ◽  
Dave Kelly
Keyword(s):  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Mast Seeding ◽  
Ecological Genomics ◽  
Theme Issue ◽  
Natural Conditions ◽  
Genetic Level ◽  
Seed Crops

The mechanisms underlying mast seeding have traditionally been studied by collecting long-term observational data on seed crops and correlating seedfall with environmental variables. Significant progress in ecological genomics will improve our understanding of the evolution of masting by clarifying the genetic basis of masting traits and the role of natural selection in shaping those traits. Here, we summarize three important aspects in studying the evolution of masting at the genetic level: which traits govern masting, whether those traits are genetically regulated, and which taxa show wide variation in these traits. We then introduce recent studies on the molecular mechanisms of masting. Those studies measure seasonal changes in gene expression in natural conditions to quantify how multiple environmental factors combine to regulate floral initiation, which in many masting plant species is the single largest contributor to among-year variation in seed crops. We show that Fagaceae offers exceptional opportunities for evolutionary investigations because of its diversity at both the phenotypic and genetic levels and existing documented genome sequences. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

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