The Influence of Plant Dispersion on Movement Patterns of the Colorado Potato Beetle, \u3ci\u3eLeptinotarsa Decemlineata\u3c/i\u3e (Coleoptera: Chrysomelidae)

The influence of plant dispersion on movements of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), was studied with mark-recapture techniques. Beetles released between potato monocultures, polycultures with two additional non-host plant species, and polycultures with five additional non-host species, randomly colonized the three types of plots. Releases between different arrangements of potted host and non-host plants showed (1) greater beetle colonization and greater length of time spent on potato plants growing alone than on potato plants surrounded by non-host vegetation, and (2) no effect of potato plant density on colonization or tenure time. Overall, there was a 65~ recapture rate; beetles consistently stayed on the same plants they originally colonized, often for at least five days after release

Response of organically and conventionally produced potatoes to a controlled attack of a pathogen

Organic agricultural products have increasing share of the food market in Europe. The questions related to benefits of organic versus conventionally produced agricultural crops are of increasing meaning. In our paper we have focused on assessment of the reaction of the immunity system of potato tubers from both agricultural systems on an external controlled attack of Phytophthora infestans, a pathogenic microorganism. The reaction of organic and conventional potato tubers was expressed via determination of chlorogenic acid. The content of chlorogenic acid in organic potato tubers increased 1.3 times after an attack, compared to potato tubers without a microbial attack. In conventional potato tubers, the increase was 4 times higher in the same way of comparison. The observed increase in conventional tubers is an evident exaggerated protection reaction to the attack of a natural potato pathogen. It is evident that there is a difference between the reaction of the immunity system of organic versus conventional potato tubers � phytoallergy

Distribution and incidence of viruses in Irish seed potato crops

peer-reviewedVirus diseases are of key importance in potato production and in particular for the production of disease-free potato seed. However, there is little known about the frequency and distribution of potato virus diseases in Ireland. Despite a large number of samples being tested each year, the data has never been collated either within or across years. Information from all known potato virus testing carried out in the years 2006–2012 by the Department of Agriculture Food and Marine was collated to give an indication of the distribution and incidence of potato virus in Ireland. It was found that there was significant variation between regions, varieties, years and seed classes. A definition of daily weather data suitable for aphid flight was developed, which accounted for a significant proportion of the variation in virus incidence between years. This use of weather data to predict virus risk could be developed to form the basis of an integrated pest management approach for aphid control in Irish potato crops

Molecular studies on the sweet potato virus disease and its two causal agents

The studies presented in this thesis contribute to an increased understanding of the molecular aspects, variability and interaction of the two most important viral pathogens of sweet potato (Ipomoea batatas L): Sweet potato feathery mottle virus (SPFMV) and Sweet potato chlorotic stunt virus (SPCSV), which cause the severe sweet potato virus disease (SPVD) when co-infecting sweet potato plants. SPVD is the most important disease affecting sweet potato in Africa, and may be the most important virus disease of sweet potato globally. The coat protein gene sequences of several African SPFMV isolates were determined and compared by phylogenetic analyses. Results showed that East African SPFMV isolates were genetically distinct. They could furthermore be divided into two serotypes which differed in their ability to systemically infect the sweet potato cultivar Tanzania. The aetiology of SPVD was studied in sweet potato plants co-infected with SPFMV and SPCSV using nucleic acid hybridisation, bioassays, tissue printing and thin section immunohistochemistry. Resistance to SPFMV in East African sweet potato cultivars was found to be due to inhibition of virus replication rather than movement and resistance was suppressed by infection with SPCSV, resulting in a ca. 600-fold increase in titres of SPFMV. Furthermore, in SPVD affected plants SPFMV is detected outside of the phloem, whereas SPCSV is detected only inside the phloem, which suggests novel as yet unknown mechanisms how SPCSV synergises SPFMV. The genomic sequence of SPCSV was determined. It was composed of two RNA molecules (9407 and 8223 nucleotides), representing the second largest (+)ssRNA genome of plant viruses. The genomic organization of SPCSV revealed novel features for the genus Crinivirus, such as i) the presence of a gene putatively encoding an ribonuclease III-like protein, ii) near-identical, 208 nucleotides long 3’-sequences on both viral RNAs, and iii) the placement of the SHP gene at a new position on the genome of SPCSV relative to other closteroviridae. Northern analyses showed the presence of several sub-genomic RNAs, of which the accumulation was temporally regulated in infected tissues. The 5’-ends of seven sub-genomic RNAs were determined using a PCR based method, which indicated that the sgRNAs were capped

Assessing the microstructural and rheological changes induced by food additives on potato puree

The effects of agar, alginate, lecithin and glycerol on the rheological properties of commercial potato puree were investigated and interpreted in terms of starch microstructural changes, and the applicability of the Cox-Merz rule was evaluated. Each additive was applied separately at two concentrations (0.5 and 1%). Microscopic observations revealed more swollen starch aggregations in lecithin and glycerol compared with those of potato puree and agar, consequently affecting the rheological properties of potato puree. All samples exhibited shear thinning non-Newtonian behaviour. Rheological measurements were strongly concentration dependent. At 0.5% concentration, additives exerted decreases in all the rheological properties of potato puree in the order of glycerol > alginate > lecithin > agar, while at 1% concentration, the order changed to glycerol > lecithin > alginate, whereas 1% agar behaved differently, increasing all rheological values. This study also showed that agar and alginate in addition to potato puree could be valuable and advantageous for further technological processes, such as 3D printing.Peer ReviewedPostprint (updated version

Adsorption of 3-chloroaniline on potato skin in aqueous solution

The adsorption behaviour of aromatic amine 3-chloroaniline (3-CA) from aqueous solution on fresh potato skin was investigated. A series of batch experiments were conducted under different experimental conditions of contact time, 3-chloroaniline concentration, weight of potato skin, pH, temperature, and ionic strength using RP-HPLC analysis. Adsorption equilibrium of 3-chloroaniline at concentration of 10 µg/mL on 1 g weight of chopped potato skin was achieved in 24 hours. Using different varieties of potato skin showed that the adsorption of 3-CA on Nicola variety is higher compared to Sante and Maris Peer varieties. Adsorption on potato skin was found to be generally higher compared to cortex and pith tissues. Analysis of adsorption isotherm shows that equilibrium data was fitted to Freundlich model (R² = 0.977). Maximum adsorption capacities of 3-chloroaniline were found in the pH range from 3 to 9, whereas low adsorption quantities were found in high acidic and high basic solutions (pH 2 and pH 13, resp.). Adsorption capacity increased with an increase in temperature from 4°C to 30°C but decreased with further increase of temperature to 40°C. Testing the ionic strength showed that increasing the concentration of electrolyte reduces the adsorption efficiency. This study indicated that the fresh potato skin (without any treatment) is possible to use as a new adsorbent for removal of 3-chloroaniline from industrial waste water