scholarly journals Retention and Transmission of Grapevine Leafroll-Associated Virus 3 by Pseudococcus calceolariae

2021 ◽  
Vol 12 ◽  
Author(s):  
Brogan McGreal ◽  
Manoharie Sandanayaka ◽  
Rebecca Gough ◽  
Roshni Rohra ◽  
Vicky Davis ◽  
...  
Keyword(s):  
White Clover ◽  
Control Strategies ◽  
Virus Transmission ◽  
Ground Cover ◽  
Host Feeding ◽  
Plant Host ◽  
Crimson Clover ◽  
Pseudococcus Calceolariae ◽  
Plant Hosts ◽  
Grapevine Leaves

Grapevine leafroll-associated virus 3 (GLRaV-3), an economically significant pathogen of grapevines, is transmitted by Pseudococcus calceolariae, a mealybug commonly found in New Zealand vineyards. To help inform alternative GLRaV-3 control strategies, this study evaluated the three-way interaction between the mealybug, its plant host and the virus. The retention and transmission of GLRaV-3 by P. calceolariae after access to non-Vitis host plants (and a non-GLRaV-3 host) White clover (Trifolium repens L. cv. “Grasslands Huia white clover”), Crimson clover (T. incarnatum), and Nicotiana benthamiana (an alternative GLRaV-3 host) was investigated. For all experiments, P. calceolariae first instars with a 4 or 6 days acquisition access period on GLRaV-3-positive grapevine leaves were used. GLRaV-3 was detected in mealybugs up to 16 days on non-Vitis plant hosts but not after 20 days. GLRaV-3 was retained by second instars (n = 8/45) and exuviae (molted skin, n = 6/6) following a 4 days acquisition period on infected grapevines leaves and an 11 days feeding on non-Vitis plant hosts. Furthermore, GLRaV-3 was transmitted to grapevine (40−60%) by P. calceolariae second instars after access to white clover for up to 11 days; 90% transmission to grapevine was achieved when no alternative host feeding was provided. The 16 days retention period is the longest observed in mealybug vectoring of GLRaV-3. The results suggest that an alternative strategy of using ground-cover plants as a disrupter of virus transmission may be effective if mealybugs settle and continue to feed on them for 20 or more days.

scholarly journals Pupal cannibalism by worker honey bees contributes to the spread of deformed wing virus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francisco Posada-Florez ◽  
Zachary S. Lamas ◽  
David J. Hawthorne ◽  
Yanping Chen ◽  
Jay D. Evans ◽  
...  
Keyword(s):  
Honey Bees ◽  
Control Strategies ◽  
Virus Transmission ◽  
Experimental Conditions ◽  
Colony Losses ◽  
Viral Pathogen ◽  
Deformed Wing Virus ◽  
Hygienic Behaviour ◽  
Pathogen Virulence ◽  
Comprehensive Knowledge

AbstractTransmission routes impact pathogen virulence and genetics, therefore comprehensive knowledge of these routes and their contribution to pathogen circulation is essential for understanding host–pathogen interactions and designing control strategies. Deformed wing virus (DWV), a principal viral pathogen of honey bees associated with increased honey bee mortality and colony losses, became highly virulent with the spread of its vector, the ectoparasitic mite Varroa destructor. Reproduction of Varroa mites occurs in capped brood cells and mite-infested pupae from these cells usually have high levels of DWV. The removal of mite-infested pupae by worker bees, Varroa Sensitive Hygiene (VSH), leads to cannibalization of pupae with high DWV loads, thereby offering an alternative route for virus transmission. We used genetically tagged DWV to investigate virus transmission to and between worker bees following pupal cannibalisation under experimental conditions. We demonstrated that cannibalization of DWV-infected pupae resulted in high levels of this virus in worker bees and that the acquired virus was then transmitted between bees via trophallaxis, allowing circulation of Varroa-vectored DWV variants without the mites. Despite the known benefits of hygienic behaviour, it is possible that higher levels of VSH activity may result in increased transmission of DWV via cannibalism and trophallaxis.

Spatial and temporal distribution of winged aphids (Hemiptera: Aphididae) frequenting blueberry fields in southwestern British Columbia and implications for the spread of Blueberry scorch virus

2006 ◽  
Vol 138 (1) ◽  
pp. 104-113 ◽  
Author(s):  
D.A. Raworth ◽  
C.-K. Chan ◽  
R.G. Foottit ◽  
E. Maw
Keyword(s):  
Control Strategies ◽  
Rhopalosiphum Padi ◽  
Virus Transmission ◽  
Temporal Distribution ◽  
Vaccinium Corymbosum ◽  
Aphis Fabae ◽  
Individual Species ◽  
Virus Vectors ◽  
Number Of Species ◽  
Trap Colour

AbstractAlate aphids were sampled in five fields of commercial blueberry, Vaccinium corymbosum L. (Ericaceae), during 2001 and 2002 using yellow tile, green tile, and Tremclad® yellow water traps. Eighty-seven species were identified among a total of 7722 alatae. Several of the species are known virus vectors, including Aphis fabae Scopoli, Brachycaudus helichrysi (Kaltenbach), Hyalopterus pruni (Geoffroy), Hyperomyzus lactucae (L.), Myzus persicae (Sulzer), Rhopalosiphoninus staphyleae (Koch), and Rhopalosiphum padi (L.). The number of species caught varied with year, and the number of species and the total number of alatae varied with field, trap colour, and season. More species were caught in 2001 than in 2002, in yellow than in green traps, and in the summer than in the spring or the autumn, and more alatae were caught in Tremclad® yellow traps than in yellow or green tile traps, and in the autumn than in the spring or the summer. However, numerous interactions limit generalizations. Analyses of the data for individual species revealed similar patterns and interactions. The effects of year, field, trap colour, and season varied with species. Given nonpersistent virus transmission and the large numbers of alatae caught of species that are known virus vectors, there is considerable potential for spread of Blueberry scorch virus by migrant aphids. Field- or area-specific and season-specific control strategies could be developed once the virus vector status of the different species is known. In addition, given the number of significant interactions observed in the data, there is a need to investigate alternative, generalized approaches to reducing virus transmission rates, such as applying whitewash or kaolin particle film to blueberry leaves.

Improving Fiji disease resistance screening trials in sugarcane by considering virus transmission class and possible origin of Fiji disease virus

2004 ◽  
Vol 55 (6) ◽  
pp. 665 ◽  
Author(s):  
Grant R. Smith ◽  
Judith M. Candy
Keyword(s):  
Disease Virus ◽  
Disease Incidence ◽  
Virus Transmission ◽  
Rating System ◽  
Plant Host ◽  
Plant Infection ◽  
Disease Resistance Screening ◽  
Disease Rating ◽  
Fiji Disease Virus ◽  
Persistently Transmitted Viruses

Fiji disease virus is a propagative, persistently transmitted virus that multiplies in species of the delphacid planthopper genus Perkinsiella, and in sugarcane, the feeding host of the insect. Efforts to improve and modify the disease rating system for Fiji disease have largely focussed on the planthopper as individual vectors of the virus, rather than as a population of the principal, or at least an alternative, host of the virus. This perspective has resulted in key parameters of disease incidence resulting from plant infection by propagative, persistently transmitted viruses being largely overlooked or misunderstood during efforts to improve the rating system. These parameters include the relatively long acquisition, latency, and transmission times, the percentage of the population containing virus, or viruliferous, in the above periods, and the effects of population density and number of plants visited on disease incidence. Suggestions to modify trial design to improve virus transmission to the plant, based on the disease incidence parameters of the propagative, persistent transmission class, are presented and the practical difficulties of implementing these proposals are discussed. In the context of fully understanding the underlying biology of this virus–insect–plant system, the hypothesis that Fiji disease virus, as a plant-infecting member of the Reoviridae, is primarily an insect virus with a secondary plant host, and may have diverged from an insect-infecting virus relatively recently is proposed and compared with other members of the family Reoviridae.

scholarly journals Citrus tristeza virus P33 Protein Is Required for Efficient Transmission by the Aphid Aphis (Toxoptera) citricidus (Kirkaldy)

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1131
Author(s):  
Turksen Shilts ◽  
Choaa El-Mohtar ◽  
William O. Dawson ◽  
Nabil Killiny
Keyword(s):  
Citrus Tristeza Virus ◽  
Transmission Rate ◽  
Control Strategies ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Transmission Mechanisms ◽  
Infectious Clones ◽  
Underlying Mechanisms ◽  
Tristeza Virus ◽  
Citrus Tristeza

Plant viruses are threatening many valuable crops, and Citrus tristeza virus (CTV) is considered one of the most economically important plant viruses. CTV has destroyed millions of citrus trees in many regions of the world. Consequently, understanding of the transmission mechanism of CTV by its main vector, the brown citrus aphid, Aphis (Toxoptera) citricidus (Kirkaldy), may lead to better control strategies for CTV. The objective of this study was to understand the CTV–vector relationship by exploring the influence of viral genetic diversity on virus transmission. We built several infectious clones with different 5′-proximal ends from different CTV strains and assessed their transmission by the brown citrus aphid. Replacement of the 5′- end of the T36 isolate with that of the T30 strain (poorly transmitted) did not increase the transmission rate of T36, whereas replacement with that of the T68-1 isolate (highly transmitted) increased the transmission rate of T36 from 1.5 to 23%. Finally, substitution of p33 gene of the T36 strain with that of T68 increased the transmission rate from 1.5% to 17.8%. Although the underlying mechanisms that regulate the CTV transmission process by aphids have been explored in many ways, the roles of specific viral proteins are still not explicit. Our findings will improve our understanding of the transmission mechanisms of CTV by its aphid vector and may lead to the development of control strategies that interfere with its transmission by vector.

scholarly journals Comparison of weed control techniques to establish three ground cover species

2010 ◽  
Vol 63 ◽  
pp. 96-101 ◽  
Author(s):  
C.L. Foo ◽  
K.C. Harrington ◽  
M.B. MacKay
Keyword(s):  
Weed Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Ground Cover ◽  
Late Spring ◽  
Control Techniques

Weed control strategies for establishing three ground cover species were investigated by planting them in late spring then assessing eight different control treatments during the following 14 months The prostrate woody Coprosma acerosa Taiko established best with black weed mat mulch and EcoCover paper mulch although bark mulches also gave reasonable establishment rates The brittle succulent Sedum mexicanum Acapulco Gold also established well with black weed mat and paper mulch although a sawdust mulch was particularly suitable The frostprone Polygonum capitatum which regrows readily from seed did best with soil kept bare by handhoeing or selective herbicides although the paper mulch also rated well Thus the best weed control strategy varied depending on the characteristics of the ground cover being established Other considerations including relative costs are also discussed

scholarly journals Redbay Ambrosia Beetle-Laurel Wilt Pathogen: A Potential Major Problem for the Florida Avocado Industry

EDIS ◽  
2008 ◽  
Vol 2008 (2) ◽  
Author(s):  
Jonathan H. Crane ◽  
Jorge E. Peña ◽  
J. L. Osborne
Keyword(s):  
Woody Plants ◽  
Management Strategies ◽  
Ambrosia Beetle ◽  
Plant Host ◽  
Laurel Wilt ◽  
Redbay Ambrosia Beetle ◽  
Plant Hosts ◽  
The U.S

HS1136, a 7-page illustrated factsheet by Jonathan H. Crane, Jorge Peña, and J.L. Osborne, describes this insect-fungal pest attacking woody plants in the laurel family, including avocado. Includes descriptions, origin, detection and spread of the pest, plant hosts in the U.S., a map of counties with the beetle, plant host symptoms and damage, management strategies & restrictions, agencies working on the issue, research and extension efforts, and references. Published by the UF Department of Horticultural Sciences, February 2008. Revised December 2008.

scholarly journals Three first records of stick insects attacking plants (Inseect: Phasmida) in Tibet

2023 ◽  
Vol 83 ◽  
Author(s):  
F. L. Xu ◽  
Y. J. Jiang ◽  
M. F. Yang ◽  
W. Da ◽  
X. W. Yang ◽  
...  
Keyword(s):  
Host Use ◽  
Plant Host ◽  
Forest Pests ◽  
Stick Insects ◽  
Plant Hosts ◽  
First Time

Abstract Except for a few stick insects that are economically valuable, most species be considered to be forest pests, so it is extremely important to obtain plant host-use information of more stick insects. In this paper, the plant hosts of three species of stick insects were recorded for the first time. We also discovered these stick insects can feed upon the flowers or leaves of plants. Lopaphus unidentatus (Chen & He, 1995) (Phasmida: Lonchodidae) attacked Hypericum choisianum Wall. ex N. Robson, 1973 (Hypericaceae), Leurophasma dolichocercum Bi, 1995 (Phasmida: Aschiphasmatidae) attacked Antenoron filiforme (Thunb.) Roberty & Vautier, 1964 (Polygonaceae) and Megalophasma granulatum Bi, 1995 (Phasmida: Lonchodidae) attacked Debregeasia orientalis C. J. Chen, 1991 (Urticaceae). Finally, we were lucky enough to also obtain photographs of them mating and feeding.

scholarly journals Sublethal Effects of Imidacloprid on Fecundity, Apoptosis and Virus Transmission in the Small Brown Planthopper Laodelphax striatellus

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1131
Author(s):  
Yuanyuan Zhang ◽  
Gang Xu ◽  
Yu Jiang ◽  
Chao Ma ◽  
Guoqing Yang
Keyword(s):  
Sublethal Effects ◽  
Control Strategies ◽  
Brown Planthopper ◽  
Virus Transmission ◽  
Rice Stripe Virus ◽  
Underlying Mechanism ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Laodelphax Striatellus ◽  
Expression Levels ◽  
Sublethal Concentrations

Laodelphax striatellus damages plants directly through sucking plant sap and indirectly as a vector of rice stripe virus (RSV), resulting in serious losses of rice yield. It is one of the most destructive insects of rice in East Asia. Insecticides are primarily used for pest management, but the sublethal concentrations of insecticides may benefit several insects. The present research attempted to explore the effects of sublethal concentrations of imidacloprid on the fecundity, apoptosis and RSV transmission in the viruliferous SBPH. The results showed that the fecundity of SBPH was significantly increased after treatment with the LC10 dose of imidacloprid, while the LC30 dose of imidacloprid reduced the fecundity compared with the control. To further investigate the underlying mechanism of increased fecundity after exposure to the LC10 dose of imidacloprid, we examined the expression levels of vitellogenin (Vg), Vg receptor (VgR) and caspases in the ovaries of SBPH, and observed the apoptosis by terminal deoxynucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL). qRT-PCR results indicated that the expression levels of Vg, VgR and four caspase genes were all significantly increased by the LC10 dose of imidacloprid, and TUNEL assays suggested that the frequency of apoptosis was significantly higher in the SBPH treated by the LC10 dose of imidacloprid, suggesting a potential correlation between the increased fecundity and the apoptosis of SBPH ovarioles. Additionally, the expression levels of RNA3 and capsid protein (CP) were both increased significantly by the LC10 dose of imidacloprid, whereas were decreased by the LC30 dose of imidacloprid compared to the control. Therefore, this study clarifies the mechanisms of sublethal effects of imidacloprid on viruliferous SBPH and could be used to optimize pest control strategies.

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