SCAPHYTOPIUS ACUTUS (SAY), A NEWLY DISCOVERED VECTOR OF CELERY-INFECTING ASTER-YELLOWS VIRUS

1962 ◽  
Vol 40 (6) ◽  
pp. 799-801 ◽  
Author(s):  
L. N. Chiykowski

Scaphytopius acutus (Say) transmitted a celery-infecting strain of aster-yellows virus from infected periwinkle (Vinca rosea L.) and aster (Callistephus chinensis Nees) to periwinkle, aster, and ladino clover (Trifolium repens L.). It acquired the virus during feeds as short as 4 hours, and transmitted it during a 2-hour feeding period. The minimum incubation time for the virus in the insect was between 21 and 26 days. After an acquisition feed of 7 days and an incubation period of at least 30 days, 11 of 21 insects transmitted the virus to separate periwinkle test plants.

1962 ◽  
Vol 40 (3) ◽  
pp. 397-404 ◽  
Author(s):  
L. N. Chiykowski

Phyllody in clovers, observed on rare occasions in Canada since 1902, is now common in Quebec, New Brunswick, Nova Scotia, and Prince Edward Island. Tests in the field indicated that natural spread of the disease could occur each month from June to September. A virus causing phyllody symptoms was transmitted by the leafhoppers Macrosteles fascifrons (Stal), Aphrodes bicinctus (Schrank), and Scaphytopius acutus (Say) from Trifolium repens L. to T. repens. M. fascifrons also transmitted the virus to and from Vinca rosea L. and Callistephus chinensis Nees. S. acutus transmitted the virus to V. rosea and Trifolium pratense L. The virus was also transmitted by dodder, Cuscuta gronovii Willd., from V. rosea to V. rosea. Clover phyllody virus (CPV) in Canada resembles CPV in England and Europe and both are transmitted by A. bicinctus. Although CPV in Canada is transmitted by M. fascifrons, which is a vector of aster-yellows virus (AYV), it differs from recognized strains of AYV in other vector–virus relationships, symptomatology, and geographic distribution.


2004 ◽  
Vol 53 (3-4) ◽  
pp. 367-376 ◽  
Author(s):  
A. A. Khalif ◽  
H. Abdorhim ◽  
Hosam E. H. T. Bayoumi ◽  
Anna Füzy ◽  
Mihály Kecskés

Üvegházi körülmények között savanyú barna erdotalajban nevelt fehér here (Trifolium repens L.) növények rizoszférájának sókezelés hatására bekövetkezo változását ellenoriztük. Megvizsgáltuk a különbözo sókoncentrációknak (0, 0,2, 0,4, 0,6 és 0,8 tömeg %) a baktériumnépesség összetételére és a különbözo talajenzimek aktivitására gyakorolt hatását.  Megállapítottuk, hogy a talaj sótartalma közvetlenül befolyásolta a rizoszférában található fluoreszkáló pszeudomonaszok csíraszámát. A legsurubb populáció a 0,2% NaCl-ot tartalmazó talajban volt mérheto, ahol a fluoreszkáló pszeudomonaszok között a Pseudomonas putida és a P. fluorescens fordultak elo a legnagyobb számban. A pszeudomonaszok ily módon jól tolerálják a talaj magas NaCl-tartalmát, és gyökérkolonizáló tevékenységet képesek kifejteni a magas NaCl-tartalmú talajban is. A sókoncentráció növelésével kezdetben (a 0,2-0,4%-os tartományban) jelentosen növekedett a dehidrogenáz, kataláz, és ureáz enzimek aktivitása. A proteáz enzimek aktivitásmaximuma a 0,1-0,2% NaCl-koncentráció tartományba esett. A 0,4%-nál magasabb koncentrációkban a kontrollhoz hasonló mértékure csökkent mind a négy enzim aktivitása, és a baktériumok száma is. A foszfatáz- és a b-glükozidáz-tevékenység viszont a NaCl-dózis növelése következtében a koncentrációval arányosan, jelentosen csökkent a kontrollhoz viszonyítva.  Feltételezésünk szerint az enzimaktivitások változását is a sókezelés hatására bekövetkezo mikrobióta összetételének megváltozása okozta.


2021 ◽  
Vol 13 (5) ◽  
pp. 2432
Author(s):  
Anna Makarova ◽  
Elena Nikulina ◽  
Tatiana Avdeenkova ◽  
Ksenia Pishaeva

Heavy metals are among the most widespread pollutants in soil. Phytoextraction technology is used to solve the problem of multi-metal-contaminated soil. The efficiency of this process can be increased by introducing various amendments. A soil amendment is any material added to a soil to improve its physical properties, such as water retention, permeability, water infiltration, drainage, aeration, and structure. Some chemical amendments for enhanced phytoextraction, such as amino polycarboxylates chelators, can be hazardous to the environment and perform poorly at pH > 8. The effect of the potassium salt of hydroxyethylidene diphosphonic acid (K2HEDP), plant growth regulators (PGRs), and iron chelate alone and in combination on the phytoextraction by Trifolium repens L. seedlings of Cd, Ni, and Cu was studied in this work. K2HEDP works in a wider pH range. The results of this study confirmed that amino polycarboxylate chelators, with the sodium salt of ethylene diamine tetraacetic acid (Na2EDTA) as an example, have a pronounced negative effect on the growth and development (organ mass) of Trifolium repens L. seedlings. K2HEDP, proposed by the authors instead of Na2EDTA, produced a pronounced positive effect on plant growth and development, which was further enhanced by the use of PGRs and with iron chelates. However, it should be noted that K2HEDP showed significantly lower efficiency in trials on the Trifolium repens L. seedlings. The highest was the efficiency of K2HEDP with PGRs and iron chelates for the phytoextraction of Cd.


Plant Science ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 531-539 ◽  
Author(s):  
Elizabeth S. Jones ◽  
Leonie J. Hughes ◽  
Michelle C. Drayton ◽  
Michael T. Abberton ◽  
Terry P.T. Michaelson-Yeates ◽  
...  

2007 ◽  
Vol 277 (4) ◽  
pp. 413-425 ◽  
Author(s):  
N. O. I. Cogan ◽  
M. C. Drayton ◽  
R. C. Ponting ◽  
A. C. Vecchies ◽  
N. R. Bannan ◽  
...  

1964 ◽  
Vol 42 (9) ◽  
pp. 1123-1133 ◽  
Author(s):  
J. T. Slykhuis ◽  
P. L. Sherwood

Endria inimica Say acquired the North American type of wheat striate mosaic virus during periods of 15 minutes or longer on diseased plants held at five constant temperatures ranging from 10 to 33 °C. When infective insects were given inoculation access periods varying from 1 to 4 days at different temperatures, the percentage of test plants infected increased with temperature from 12.5% at 10° to 81.4% at 33 °C. After an acquisition access period of 2 days at 24 °C, insects kept at 8 or 10 °C did not transmit virus, but the percentage of others that transmitted at successively higher temperatures increased from 3.3% at 16 °C to 73.3% at 33 °C. The preinfective period was more than 29 days for insects kept at 16 °C and only 5 days for some kept at 27, 30, and 33 °C. The average preinfective period was 11 days at 20 °C, but decreased to 6.4 days as temperature increased to 33 °C. The percentage of test plants that became infected increased from 0.1% at 16 °C to 44.3%, at 33 °C. Stewart and Ramsey wheat seedlings exposed to infective E. inimica for 2 days did not develop symptoms during a subsequent 60 day period at 10 °C. After the same plants were placed in a greenhouse at 20–25 °C, 26% and 27%, respectively, developed symptoms. The incubation period for symptoms in plants ranged from 17 to more than 62 days at 16 °C. It decreased as temperature increased but varied from 6 to 25 days at 30 °C. Forty-two and 48% of Stewart and Ramsey wheat plants respectively, developed symptoms at 16 °C, and increased to almost 100% for both varieties at 30 and 33 °C. The above results indicate that high temperatures during early summer are prerequisite for severe epidemics of wheat striate mosaic in spring wheat.


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