Vectors Of Potato Viruses Research Articles

Virus Infection and Host Plant Suitability Affect Feeding Behaviors of Cannabis Aphid (Hemiptera: Aphididae), a Newly Described Vector of Potato Virus Y.

Aphids are the most prolific vectors of plant viruses resulting in significant yield losses to crops worldwide. Potato virus Y (PVY) is transmitted in a non-persistent manner by 65 species of aphids. With the increasing acreage of hemp (Cannabis sativa L.) (Rosales: Cannabaceae) in the United States, we were interested to know if the cannabis aphid (Phorodon cannabis Passerini) (Hemiptera: Aphididae) is a potential vector of PVY. Here, we conduct transmission assays and utilize the electrical penetration graph (EPG) technique to determine whether cannabis aphids can transmit PVY to hemp (host) and potato (non-host) (Solanum tuberosum L.) (Solanales: Solanaceace). We show for the first time that the cannabis aphid is an efficient vector of PVY to both hemp (96% transmission rate) and potato (91%) using cohorts of aphids. In contrast, individual aphids transmitted the virus more efficiently to hemp (63%) compared to potato (19%). During the initial 15 min of EPG recordings, aphids demonstrated lower number and time spent performing intracellular punctures on potato compared to hemp, which may in part explain low virus transmission to potato using individual aphids. During the entire 8-hour recording, viruliferous aphids spent less time ingesting phloem compared to non-viruliferous aphids on hemp. This reduced host acceptance could potentially cause viruliferous aphids to disperse thereby increasing virus transmission. Overall, our study shows that cannabis aphid is an efficient vector of PVY, and that virus infection and host plant suitability affect feeding behaviors of the cannabis aphid in ways which may increase virus transmission.

Monitoring of aphid populations - the vectors of potato viruses

Monitoring of aphid populations - the vectors of potato viruses

Species Composition of Aphids (Hemiptera, Aphididae) on Seed Potato Plantings in Northwest Russia

Collections using yellow water traps revealed from 20 to 43 species of aphids on seed potato plantings in the farms of Northwest Russia in 2013–2017. Among them, from 2 to 5 species were vectors of potato viruses; aphids of these species together comprised 12.5–36% of the total number of captured aphids. The remaining 18–38 aphid species attracted to yellow traps were associated with vegetable, fruit and berry crops, weeds, trees, and shrubs surrounding potato plantings in the study areas. The species number and abundance of aphids depended on weather conditions, insecticide treatments, and the presence of home gardens near the traps. Up to 7 aphid species feeding on potatoes were recorded using the “100 leaves” sampling method; 6 of them are vectors of viral potato diseases: Aphis fabae Scop., A. nasturtii Kalt., A. frangulae Kalt., Aulacorthum solani Kalt., Macrosiphum euphorbiae Thomas, and Myzus persicae Sulz.

The effects of monitoring the abundance and species composition of aphids as virus vectors on seed potato production in Serbia

Aphids are the most important vectors of potato viruses during the crop?s growing season. The most widespread and damaging viruses, the potato virus Y and potato leaf roll virus, are transmitted by aphids in non-persistent and persistent manner, respectively. The two viruses cause the greatest concern of potato producers and a great constraint to seed potato production in Serbia, the region and across the world. Potato virus Y is particularly harmful, given its distribution and spreading rate. Seed potato production systems under well-managed conditions involve a series of virus control measures, including the monitoring of outbreaks of winged aphids, their abundance and species composition, in order to forecast virosis, i.e. potential plant and tuber infection periods. Monitoring the aphid vectors of potato viruses enables determination of optimum dates for haulm destruction when higher than normal numbers of winged aphids as vectors of economically harmful diseases have been observed. Haulm destruction in a potato crop reduces the risk of plant infection and virus translocation from the aboveground parts to tubers, thus keeping the proportion of infected tubers within tolerance limits allowed for certain categories of seed potatoes. This practice has positive effects if used in combination with other viral disease control measures; otherwise, it becomes ineffective. This paper provides an integral analysis of the effects and role of monitoring outbreaks of aphids, their abundance and species composition in timing haulm growth termination to prevent plant infection, virus translocation and tuber infestation in potato crops in Serbia and the wider region.

The pressure of Aphids (Aphididae, Hemiptera), vectors of potato viruses

Plant viruses and aphids as their vectors, are limiting factors in the production of healthy seed potato. Potato Virus Y (PVY) and Potato Leafroll Virus (PLRV) are the two most significant potato viruses in Europe, and seed quality depends directly on the infection level. In order to determine the possibilities for healthy seed potato production in Serbia, aphid flight activities have been monitored for four years in four localities. Over 6400 specimens of aphids have been collected. The number of aphids and vector pressure index varies depending on the localities? altitude. In localities at altitudes under 1000 m, they were high. The highest index was in locality Kotraza in 2007, when the PVY index exceeded the value of 180, while for PLRV it was 60. At high altitudes, above 1100 m, the number of aphids was low, as was the vector pressure index. The lowest index values were recorded in localities on Mt. Golija at 1300 m a.s.l. where the indexes for both viruses never exceeded value 6.

Transgenic or plant expression vector-mediated recombination of Plum Pox Virus.

Different mutants of an infectious full-length clone (p35PPV-NAT) of Plum pox virus (PPV) were constructed: three mutants with mutations of the assembly motifs RQ and DF in the coat protein gene (CP) and two CP chimeras with exchanges in the CP core region of Zucchini yellow mosaic virus and Potato virus Y. The assembly mutants were restricted to single infected cells, whereas the PPV chimeras were able to produce systemic infections in Nicotiana benthamiana plants. After passages in different transgenic N. benthamiana plants expressing the PPV CP gene with a complete (plant line 4.30.45.) or partially deleted 3'-nontranslated region (3'-NTR) (plant line 17.27. 4.), characterization of the viral progeny of all mutants revealed restoration of wild-type virus by recombination with the transgenic CP RNA only in the presence of the complete 3'-NTR (4.30.45.). Reconstitution of wild-type virus was also observed following cobombardment of different assembly-defective p35PPV-NAT together with a movement-defective plant expression vector of Potato virus X expressing the intact PPV-NAT CP gene transiently in nontransgenic N. benthamiana plants. Finally, a chimeric recombinant virus was detected after cobombardment of defective p35PPV-NAT with a plant expression vector-derived CP gene from the sour cherry isolate of PPV (PPV-SoC). This chimeric virus has been established by a double recombination event between the CP-defective PPV mutant and the intact PPV-SoC CP gene. These results demonstrate that viral sequences can be tested for recombination events without the necessity for producing transgenic plants.

The efficiency of the bulb and potato aphidRhopalosiphoninus latysiphon (Davidson) as a vector of potato virus V

Experiments to test the ability ofRhopalosiphoninus latysiphon to transmit potato virus V showed a transmission rate of 16 per cent after only two weeks; this was maintained for a further two weeks, beyond which time the rate rose rapidly. A comparison of the mode of inoculation of PVV byR. latysiphon andMyzus persicae suggested that the mechanism may be similar for both species.

Reevaluation of the potato aphid,Macrosiphum euphorbiae (Thomas), as vector of potato virus Y

The effectiveness of the potato aphid,Macrosiphum euphorbiae (Thomas), to transmit potato virus Y (PVY) to potato has generally been overestimated because tobacco has been used as the indicator host. Our results demonstrate that, although apterousM. euphorbiae can acquire PVY from potato and tobacco plants and transmit it to tobacco plants, it does not readily transmit it to potato plants. Alatae only transmitted the virus to 4.5% of potato plants. This relative inability to transmit the virus to potato seems independent of potato cultivar. Results suggest that the role of the potato aphid in the spread of PVY in potatoes may be negligible.

Roquette,Eruca vesicaria subsp.sativa a good host for long-term maintenance of aphid vectors of potato viruses

Since 1971, we have used roquette,Eruca vesicaria (L.) Cav. subsp.sativa (Mill.) Thell., as a host for prolonged maintenance of colonies of the green peach aphid,Myzus persicae (Sulzer), and the potato aphid,Macrosiphum euphorbiae (Thomas). When roquette plants were kept in a growth chamber with 12 hour light and dark periods and a temperature regime of 20°C light and 15°C dark, or in greenhouse cubicles with temperatures ranging from 22–28°C and light periods ranging from 12 to 14 hours, colonies of these aphids could be maintained on a single plant for 16 weeks. These aphids retained their original characteristics, readily accepting radish, lettuce, and snapdragon as hosts, but accepted chrysanthemum only with great reluctance. Aphids from colonies that were maintained on roquette for 4 years did not lose their ability to transmit viruses.

Aphis Migration and the Efficiency of the Trapping Method

Reproducible results were obtained when adhesive traps for aphides were placed at the same height in different parts of a potato field. The total catches in different localities in different seasons can therefore justifiably be compared. During the summer dispersal flights, different species flew at different heights, so traps at one height only are not suitable for comparing the relative abundance of different species. There was less variation in numbers caught on traps at 3–4 ft. above the ground than on traps at 5–6 ft. or at ground‐level.During the first fortnight of July an average of 200 aphides, 1.6% of which were Myzus persicae, was caught on traps in the position of potato plants. Most of these were not potato aphides, but it is suggested that some of them might act as vectors of potato viruses. The number of aphides caught was roughly proportional to the volume of free air space around the traps, and as the foliage increased in density the numbers caught on lower traps decreased in proportion.Wind‐speed records within and above the crop are discussed and it is shown that conditions are often suitable for voluntary aphis flight in and near the crop on relatively windy days. Records of catches on the half‐traps facing the wind and on the other halves showed that voluntary flight decreased with increasing height.Brilliant yellow traps, coated with adhesive grease, caught more aphides than white traps, which in turn caught more than black.