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

2014 ◽  
Vol 29 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Drago Milosevic ◽  
Slobodan Milenkovic ◽  
Pantelija Peric ◽  
Svetomir Stamenkovic

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.

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 679-685 ◽  
Author(s):  
R. P. Singh ◽  
D. L. McLaren ◽  
X. Nie ◽  
M. Singh

Surveys of commercial and seed potato fields for virus diseases (1998 to 2002) in Manitoba established that Potato virus Y (PVY) is of concern in seed potato production. To determine the prevalence of PVY strains, PVY-infected tubers identified by reverse transcription-polymerase chain reaction (RT-PCR) from surveys (2000 to 2001) were grown for symptom expression and strain characterization by strain-specific RT-PCR, bioassays, and serological assays. Of the samples collected (2000 to 2001) and tested by RT-PCR, 4.0% contained PVY. Further analysis of the PVY-positive samples by a duplex RT-PCR facilitating the simultaneous detection of common (PVYO) and tobacco veinal necrosis strains (PVYN/NTN) indicated that 37.5% contained PVYO and 63.5% contained PVYN-type isolates. Analysis of the PVYN-type samples using three monoclonal antibodies (MAbs) showed that all reacted with only the PVYO MAbs and not with the PVYN-specific MAb. Partial nucleotide sequences of both ends of PVY-RNA showed that the PVYN-type isolates resembled those reported in 1996 from Manitoba. These isolates are designated as PVYN:O. In view of the increased incidence of PVYN:O in one production area, seed tubers imported from other provinces of Canada and the neighboring United States were analyzed for PVYN:O. The PVYN:O was detected in imported seeds from Minnesota, Montana, and North Dakota.


Redia ◽  
2020 ◽  
Vol 103 ◽  
pp. 75-85
Author(s):  
AMEN HLAOUI ◽  
EMANUELE MAZZONI ◽  
REBHA SOUISSI ◽  
SONIA BOUKHRIS BOUHACHEM

Aphid flight activities were monitored in 2015 in two areas of seed potato production in Tunisia. Yellow water traps were used to investigate the diversity of aphidofauna and the incidence of aphids involved in potato virus transmission. A total of 9966 specimens belonged to 73 taxa were captured. The cumulative abundance recorded in Douala (first site) was much higher than in El Ogla (second site) (8768 vs 1189 specimens). The most preponderant species in Douala were Aphis spiraecola Patch (66.1%) and Aphis spp. group (13.5%). In El Ogla Rhopalosiphum padi (L.) comprised 58.9% of total catches, followed by Acyrthosiphon pisum (Harris) (12%) and Aploneura lentisci (Passerini) (10.4%). The highest values of diversity indices were recorded on April 23 th [Shannon-Wiener index (H’)=2.58; Simpson index (1-D)=0.88] in Douala and on May 12th (H’=1.70; 1-D=0.75) in El Ogla. The detection of viral infections by DAS-ELISA determined the predominance of Potato virus Y amongst five main potato viruses tested. Overall Chi-square analysis determined significant differences crossing all areas of seed and ware potatoes and season crops. The highest incidence of viruses was recorded in Douala (18.5%) while El Ogla was under the threshold value (4%). This might be attributed to the occurrence of aphids in early season known previously to be efficient vectors of PVY and to the characteristics of area including climatic conditions, altitude and landscape structure. These results provide new evidence for El Ogla as ideal site to produce healthy tubers while conversely Douala is favourable for the propagation of vectors and viruses.


2012 ◽  
Vol 27 (2) ◽  
pp. 97-106 ◽  
Author(s):  
Drago Milosevic ◽  
Svetomir Stamenkovic ◽  
Pantelija Peric

Viruses occurring in Serbia and other countries in the region are a huge problem constraining seed potato production. At lower altitudes, in lowland and hilly regions, where table potato production is widely distributed, more than 50% of healthy plants become infected with potato virus Y during one growing season. Under these conditions, seed potato production is hindered due to a high infection pressure of potato virus Y which spreads far more rapidly compared to leaf roll virus, virus S and other viruses hosted by this plant species. This study tended to clarify a frequent dilemma regarding the use of insecticides in preventing the infection of healthy plants with potato virus Y and leaf roll virus, given the oral and written recommendations from pesticide manufacturers, agronomists and scientists in the field of crop protection arising from a logical conclusion that aphid vector control results in virus transmission control. The present findings, which are in agreement with reports of authors from other countries, show that the use of insecticides is ineffective in preventing potato virus Y which is nonpersistently transmitted by aphids from an external source of infection. However, insecticides can exhibit efficacy in preventing potato virus Y transmission from infected plants to healthy plants within a crop, which can have an overall positive effect only if seed potato is grown in areas that have no external source of infection. The present results and those of other authors show that insecticides are effective in preventing the infection of healthy plants with persistently transmitted leaf roll virus. Mineral oils provide effective control of potato virus Y by preventing the infection of potato plants with the virus. They can be combined with other management practices to protect seed potato crops against the virus. Given the fact that the initial first-year infection of healthy potato plants with virus Y in relation to leaf roll virus is approximately 10-20:1 under conditions in Serbia, and that the use of insecticides fails to ensure protection against PVY, this practice cannot have any positive effect on virus control under high infection pressure conditions.


Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 430-430 ◽  
Author(s):  
A. Quintero-Ferrer ◽  
A. V. Karasev

Potato virus Y (PVY) is a serious problem for potato production worldwide. The virus reduces both tuber yield and quality, and recent spread of recombinant strains of PVY in potato production areas is largely credited with the spread of potato tuber necrotic ringspot disease (PTNRD) (1). In Mexico, recombinant strains of PVY were reported in at least two states, Chihuahua (4) and the State of Mexico (3); however, no surveys have been conducted in other potato-producing areas, and the spectrum of PVY isolates circulating in the country has remained uncharacterized. In October 2011, a small-scale survey of seed potato was conducted in the state of Jalisco, Mexico, to identify PVY isolates present in fields. Twelve seed potato fields were inspected visually. These represented various generations of seed potato, from nuclear to G2. Leaf samples were collected from plants displaying mosaic, crinkling, and yellowing symptoms, and were tested for PVY. Fifty samples were collected from cultivars Fabula, Mondial, Fianna, Gigant, Caesar, and Adora. Of the 50 leaf samples collected, seven were PVY-positive using the Immuno-strip Kit (Agdia, Elkhart, IN), and six of these were determined to have a N-serotype according to the typing by the Pocket Diagnostics lateral flow kit (Forsite Diagnostics, Ltd., York, UK). PVY-positive samples came from cultivars Fabula (2 with N serotype), Mondial (4 with N serotype), and Fianna (1 with O serotype). Extracts of the seven PVY-positive leaf samples were applied to Whatman FTA cards (Sigma, St. Louis, MO), dried, and transported to the Plant Virology Laboratory at the University of Idaho for further characterization. All samples immobilized on FTA cards were subjected to RNA extraction and standard reverse transcriptase (RT)-PCR typing using a set of PVY-specific primers (2) to determine the strain type. All PVY isolates were recombinant. The six N-serotype samples were found to contain recombinant PVYNTN isolates and produced characteristic bands of 181 and 452 bp in RT-PCR, which indicated the presence of two recombination junctions in the HC-Pro/P3 and VPg regions typical of European PVYNTN isolates. The one O-serotype sample was identified as a recombinant PVYN-Wi/N:O isolate, and produced 181 and 689 bp bands in RT-PCR, which indicated the presence of one recombination junction in the HC-Pro/P3 region. Sequence analysis of RT-PCR products amplified from five samples with N serotype identified them as PVYNTN isolates, and from the one with O serotype identified it as PVYN-Wi/N:O isolate. Sequence comparisons confirmed that N serotype samples contained PVY isolates most closely related to typical PVYNTN sequences (Accession No. EF026075), while the O serotype sample contained the PVY isolate most closely related to PVYN-Wi from Europe (HE608963). The data obtained suggest the presence of two different types of PVY recombinants, PVYNTN and PVYN-Wi, in seed potato in Jalisco. Additional surveillance for these recombinant isolates may be needed, as well as a survey of their effects on tuber quality in production areas. This is the first report of recombinant isolates of PVY often associated with PTNRD circulating in seed potato in Jalisco, Mexico. References: (1) S. M. Gray et al. Plant Dis. 94:1384, 2010. (2) J. H. Lorenzen et al. Plant Dis. 90:935, 2006. (3) V. R. Ramirez-Rodriguez et al. Virol. J. 6:48, 2009. (4) L. Robles-Hernandez et al. Plant Dis. 94:1262, 2010.


2018 ◽  
Vol 10 (3(J)) ◽  
pp. 122-140
Author(s):  
Ambrose Rwaheru Aheisibwe ◽  
Razack B. Lokina ◽  
Aloyce S. Hepelwa

This study established the level of technical efficiency and its determinants among the informal and formal seed potato producers in the southwestern highlands agro - ecological zone of Uganda. A multi- stage sampling procedure was employed to select 636 households (499 informal seed producers and 137 formal seed producers) from which data was collected for two seasons using a semi - structured questionnaire. Data was analyzed using the stochastic frontier approach with a one - step approach. Maximum likelihood estimates for the efficiency parameters showed that both informal and formal seed potato producers were not fully efficient. The mean technical efficiency for informal and formal seed potato producers was 8 1 .4 and 80.4 percent respectively. In terms of yield loss, informal and formal seed potato producers respectively lost an average of 981 and 1,208 kg/acre of seed potato tubers due to inefficiency factors . Specifically, off- farm income source, scale of production, seasonal variation, access to extension services and seed producer being male positively influenced informal seed producers’ technical efficiency while producers’ level of education and seed potato variety diversity negatively influenced their efficiency. For formal seed producers, technical efficiency was influenced positively by producers’ education and negatively by household size. The study suggests that there is an opportunity to improve technical efficiency of informal and formal seed producers by 19 and 20 percent respectively. Therefore, this calls for increased investment in developing and promoting high yielding varieties, provision of extension services, input intensification and addressing gender issues in seed potato production in the context of limited arable land .


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