Monitoring of aphids - vector of potato diseases virus - continued in Poland for 30 years in 5 localities, indicated some changes in pressure exerted by these insectes. The biggest differences were observed for Macrosiphum euphorbiae (Thom.) and subsequently for Aphis frangulae Kalt. and Aulacorthum so/ani Kalt. Reduction in population of these aphids has been observed according to elapsing time in all five localities. In case of Myzus persicae (Sulz.) or Aphis nasturtii Kalt., these changes involved decrease or increase of the pressure, depending on the locality.

The cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae), has become a widespread pest causing serious losses in several economically important crops, particularly cotton. To the best of our knowledge this is the first record of cotton mealybug, P. solenopsis as a new pest of potato plants in Egypt. The insect was noticed on potato plants for the first time during the growing season of 2016 (mid-August 2016). Mealybug specimens were collected from infested potato plants and identified as P. solenopsis. In an attempt to control this insect pest species, seven insecticides viz. sulfoxaflor, abamectin + thiamethoxam, spirotetramat, thiamethoxam, imidacloprid, buprofezin, and pymetrozine, belonging to different chemical groups, were tested for their effect against nymphs and adult females of P. solenopsis on potato under field conditions. The obtained results indicated that sulfoxaflor, abamectin + thiamethoxam and spirotetramat had the highest efficacy against P. solenopsis recording 80.3–96.05% reduction of the insect population after 21 days of application. Thiamethoxam, imidacloprid, buprofezin and pymetrozine failed to exhibit sufficient P. solenopsis control.

Thirty-six species of plant parasitic nematodes were found associated with poor growth of potato plants in the Wielkopolska region. In this paper the species are listed, with frequency in samples and locality of sites.

The investigations were carried out at Bonin during I 996-1999. The aim of the study was the comparison of PVY, PVS, PVM and PLRV infection pressure in different periods of growing season. The PVY pressure was the greatest. The mean (of 4 years) infection was 32%. Evidently lower infection was observed for PVS (19%) and PVM (7%) and extremely low for PLRV (only O.Ol%). The most intense spread of PVY, PVS and PVM took place from second IO days of July until first ten days of August.

The paper reports results of investigations concerning the influence of saponin extract of quillaja on the food choice and development of Colorado potato beetle. Choice tests with the use of potato leaf discs treated and untreated with tested saponins’ extract were made. The influence of the presence of saponins on the food choice and intensity of insect feeding were observed. It was stated that saponins significantly restrain feeding and disturb development of this pest.

In the years 2000–2003 under Polish climatic conditions early blight occurred at different level of incidence on over 90.6% of surveyed fields. Time of disease appearance in different regions was closely related to climatic conditions. On average, early blight appeared on potato plants 59.3 days after planting, earlier than late blight. In the years 2001–2003, efficacy of six selected fungicides in early blight control was examined in field conditions. Experiments carried out in the Department of Potato Protection and Seed Science of Plant Breedingand Acclimatization Institute. Field trials located in two sites – at Bonin and Stare Olesno revealed much slower development of early blight on these fields where chemical protection was applied as compared to untreated control. Efficacy of plant protection program carried out in Bonin over three years varied from 40% to 63.9%. Effectiveness of selected products was higher in Stare Olesno at higher infection pressure, and ranged from 49.8% to 66.6%. However, efficiency of chemical protection in early blight suppressing is not as satisfactory as in late blight control. In field experiments good control of early blight resulted in tuber yield increase. In Bonin yield increase varied from 5.5 to 24.2% and in Stare Olesno from 12.2 to 34.4%.

As compared to 1977 potato acreage in Poland has decreased by about 1.4 million hectares and amounted to 958 thousand hectares in 2002. Potatoes are protected mainly against Leptinotarsa decemlineata Say, Phytophthora infestans and weeds. Number of chemical treatments against Colorado potato beetle fluctuated between 1.1. to 1. 7 per year, in average. In 1977-1987 mainly organophosphorous insecticides were applied, whereas in last years pyrethroids and nereistoxin were used. Chemical treatments against late blight fluctuated between 1.2 to 1.6 per year, in average. Observations performed in 1977-2002 showed that the application of contact fungicides considerably decreased. In weed control in potatoes only one treatment, in average, was performed using herbicides, mainly pre-emergence ones. Herbicides containing linuron and metribuzin were most frequently applied.

In Poland, about sixty fungicides are registered for chemical protection of potato crops against late blight (Phytophthora infestans) and some of them are effective against early blight (Alternaria spp.). Time of appearance of pathogens in potato crops depends on climatic conditions. In Bonin climatic conditions in the years 1998-2002, early blight was observed at the earliest date i.e. 41-56 days after potato planting. Trials carried out at the Plant Breeding and Acclimatization Institute Bonin have shown different usefulness of fungicides in control of some pathogens of potato. The tested fungicides varied in their mobility (contact, translaminar, systemic) and activity against pathogens (protectant, curative, eradicative). All tested fungicides were effective in control of late blight in potato crops. They inhibited the rate of late blight development and in most cases the differences of their effectiveness were not significant. Systemic fungicides with slower mobility have the best efficacy in control of late blight infections occurring on potato stems. In laboratory tests, mancozeb, propineb and mixture of metalaxyl and mancozeb were significantly more effective in inhibiting the development of Alternaria. Fungicides, which are effective in the control of different pathogens, are particularly useful in potato protection programs.

Soil, the main element of natural environment is constantly contaminated and degraded by various man's activities. Big industrial factories, which emit to the atmosphere excessive quantities of harmful solid, liquid and gaseous substances, are the main cause of this phenomenon. Lm proper usage of fertilisers and chemical plant protection agents effects the soil in a lesser degree, but it is still unfavourable. The aim of this research was to use potato beetle larva in stage L4 as a soil bioindicator fi-om the plantations of spring wheat, potatoes, and corn which were treated with herbicides. The obtained results did not show any negative effect of herbicides used on potato beetle larva growing in the soil.

Water extractsfrom selected Geraniaceae plants, to which paraffin oil was added as adjuvant, were tested. It was observed that the plant extracts researched limited Colorado potato beetle feeding and development and adding adjuvant increased the effects. The highest antifeedant activity towards Colorado potato beetlesand their larvae wasobs erved in extractsobtained from Pelargonium × hortorum Bailey and Geranium pusillum L. The extract from Pelargonium × hortorum Bailey added to food showed a negative effect on the development of female reproductive organs and embryo development and showed the highest effectiveness in field conditions.

Potato white mold caused by Sclerotinia sclerotiorum is an important plant disease occurring in many potato-producing areas throughout the world. In this study, a specific diagnostic method was used to detect and quantify S. sclerotiorum ascospores, and its forecasting ability was assessed in potato fields during flowering periods of 2011 to 2014 in Bahar County, Hamedan Province. Using GenEMBL database, a primer pair, HZSCREV and HZSCFOR, was designed and optimized for the pathogen. After testing the sensitivity of primers, DNA was extracted from samples of outdoor Burkard traps from potato fields. A linear association was observed between pathogen DNA and the number of ascospores using the quantitative PCR (qPCR) technique in the presence of SYBR dye. The qPCR could successfully detect DNA amounts representing two S. sclerotiorum ascospores and was not sensitive to a variety of tested fungi such as Botrytis cinerea, Alternaria brassicae, Fusarium solani. In contrast to the amount of rainfall, a direct relationship was found between ascospore numbers and the incidence of potato white mold from 2011 to 2014.

The efficacy of solar heat in the control of bacterial soft rot of potato tubers was investigated in Maiduguri, semi-arid region of Northeastern Nigeria. Artificially contaminated tubers were exposed to solar heat for duration of 0, 30, 60, 120 and 180 minutes. The results showed that exposures for 120 and 180 minutes gave the highest control of the disease, although during the hot dry season (mean temperature at exposure was 54.6°C) exposure even for 30 minutes gave satisfactory control of the disease. Solar heat can therefore be used to control of bacterial soft rot of potato tubers.

Potato virus Y (PVY) is one of the most destructive viruses infecting potato in Egypt and worldwide. Recent research has shown that a necrotic PVY-NTN strain is infecting potato in Upper Egypt. Chemical control is not effective to control this viral pathogen. An alternative to control PVY infecting potato is using a mild PVY strain to elicit systemic cross protection in potato plants against infection with a severe necrotic strain of PVY. Results of this study showed that a PVY necrotic strain produced a significant lesser number of local lesions on diagnostic plants (Robinia pseudoacacia L.) when these plants were treated first with a mild PVY strain. Data obtained from greenhouse and field experiments indicated that treatment of potato plants (variety Burna) with a mild PVY strain significantly protected potato from infection with a severe necrotic PVY strain, and resulted in a significant increase in tuber yield compared with infected plants without prior treatment with a mild PVY strain. The highest increase in potato tuber yield was obtained when potato plants were inoculated with a mild PVY strain 3 days before challenging with the severe necrotic PVY strain. This study proved that using a mild strain of PVY can significantly protect potato plants from infection with a severe strain of this virus under both greenhouse and field conditions and can present a potential method to reduce losses due to infection of this virus in Assiut governorate and Upper Egypt.

Potato (Solanum tuberosum L.), an important food crop in the world, is susceptible to many fungal pathogens including Alternaria solani and Fusarium oxysporum causing Fusarium wilt and early blight diseases. Mycoparasitic fungi like Trichoderma encode chitinases, cell wall degrading enzymes, with high antifungal activity against a wide range of phytopathogenic fungi. In this study, a binary vector harboring endochitinase gene of ~1,000 bp was constructed and used to transform potato nodes through Agrobacterium-mediated transformation. Out of several primary transformants, two transgenic potato lines were verified for transgene insertion and integration by Southern blot. In a pot experiment for Fusarium resistance, the transgenic potato lines didn’t show any symptoms of disease, instead they remained healthy post infection. The transgenic potato lines exhibited 1.5 fold higher mRNA expression of endochitinase at 7 days as compared to 0 day post fungus inoculation. It was evident that the mRNA expression decreased over days of inoculation but was still higher than at 0 day and remained stable upto 30 days post inoculation. Similarly, for A. solani infection assay, the mRNA expression of the endochitinase gene was 3 fold higher 7 days post inoculation compared to expression at 0 day. Although the expression decreased by1.2 fold during subsequent days post infection, it remained stable for 30 days, suggesting that protection in transgenic potato plants against fungal pathogens was achieved through an increase in endochitinase transcript.

During potato desiccation the above-ground parts can be destroyed by mechanical, mechanical-chemical, or chemical methods. In the current study, the mechanical-chemical method was used and instead of chemical compounds natural nonanoic acid (pelargonic acid) was used. Nonanoic acid is a natural active ingredient that can be extracted from vegetable oil (rapeseed oil). It is a short chain fatty acid and a natural product, that fits well with the principles of the Green Revolution, which has introduced restrictions worldwide on the use of chemical plant protection products and promotes natural ones. For comparison carfentrazone-ethyl and glufosinate-ammonium were used. Studies were carried out in Poland during 2012–2014 with the potato variety Ikar, which is known to be among the varieties difficult to desicccate in Poland. The results show that potato leaves were efficiently destroyed by both nonanoic acid and chemicals (carfentrazone-ethyl and glufosinate-ammonium). The level of destruction varied from 94.5% to 99%. The level of stalk drying caused by nonanoic acid was high and it was similar to that of chemical desiccants. None of the studied desiccants significantly affected yield, vascular necrosis or quantity of starch in tubers.

The studies conducted in two different localities revealed variable time of occurrence and severity level of potato early blight (Alternaria spp.). Each year at Stare Olesno the early blight caused considerable destruction of potato plants (90.2%-95.4%) while at Bonin the disease severity differed in particular years and ranged from 50.0% to 97.5% of destructed plants at the end of the growing season. Field trials showed good efficacy of fungicides selected for controlling the early blight compared with an untreated control. Spraying with fungicides limited development of the disease and increased tuber yield in the range from 21.9% to 60.9% for Bonin and from 13.0% to 101.9% for Stare Olesno surveys. The mixture of zoxamide with mancozeb showed the greatest efficacy.

The genetic resistance of potato varieties can be utilized to lower the fungicide rates used for plant protection against late blight. The very resistant varieties can be protected with half the rate of fungicide without negative effect on efficiency of the con troi.

The research on the repellent effect of Tanacetum vulgare L. on Colorado potato beetle (Leptinotarsa decemlineata Say) was conducted in 1997-2000. The results, which were obtained from the laboratory and field examinations, showed a good effectiveness against beetles as well as their individual development stages. Powdered leaves and flowers of the plant both in powdered form and in water slurry were used in the experiments. Due to the lack of its toxic effect on man, T. vulgare can be used in small potato plantations near settlements as well as in ecological farms.

Two potato cultivars, sprayed and nonsprayed with fungicides, were evaluated to determine the association of late blight (caused by Phytophtora infestans) and radiometric leaf reflectance to disease development. Spectral radiance measurements were taken with Cl MEL CE3132 luminancemeter in the visible (450 nm, 550 nm and 650 nm) and near-infrared (850 nm) range of the electromagnetic spectrum. The measurements were taken at two view zenithal angles.ó.> 0° (at nadir) and o.> 50°. Six vegetative indices based on these measurements were used to detect differences between sprayed and nonsprayed plants. Vegetation indices based on the reflectance measurement enable to distinguish infected potato plants from noninfected plants. Among the vegetation indices used in this studies the best indicators of disease were NlR/RED and ELA!. Results of our study show that for Mila cultivar oblique viewing may be more effective then nadir viewing (perpendicular to the ground surface) for distinguishing between plants infested at different degree.

The purpose of the studies carried out in the years 1996-1998 was to establish the composition of bacteria and fungi communities in the potato rhizosphere and non-rhizosphere soil. Besides, in the examined samples the studies established the proportion of bacteria and fungi antagonistic towards soilbome pathogens. The microbiological analysis of 1 g of dry weight of soil coming from the rhizosphere of potato revealed from 3.96 x 10' to 7 .26 x 10 6 bacteria colonies and from 51.38 x 103 to 69.96 x 103 fungi colonies. In the case of nonrhizosphere soil of 1 g of dry weight of soil revealed from 3.50 x 10' to 4.75 x 106 bacteria colonies and from 16.16 x 103 to 34.1 0 x 103 fungi colonies. Moreover, potato cultivation had a positive effect on the increase of numbers of antagonistic bacteria (Bacillus spp. and Pseudomonas spp.) and fungi (Gliocladium spp., Penicillium spp., Trichoderma spp.). A larger number of the communities of bacteria and fungi, including antagonistic ones, in the root area of potato, indicates considerable biological activity, which contributes to a better phytosanitary condition of the soil.

The effect of some terpenoid lactones (monocyclic ó-hydroxy-v-lactone: bicyclic &-hydroxy-y-spirolactone and bicyclic &-hydroxy-y-lactone) and azadirachtin on feeding and growth of Leptinotarsa decemlineata Say larvae was studied. Among lactones bicyclic 6-hydroxy-y-spirolactone showed a strong feeding deterrency. Larvae treated with this compound consumed O.I63 cm2 (per larva) of potato leaves during 6 days, whereas control larvae ate 0.892 cm2• When lactones were used, a slight increase in body weight was observed. Azadirachtin, in comparison with lactones, much stronger reduced food consumption and growth rate of insects.

A biotic interaction between fungi from soil within and outside the rhizosphere of potato and fungi responsible for black scurf – Rhizoctonia solani Kühn and silver scurf – Helminthosporium solani (Dur., Mont.). It was found that fungi population connected with crop environment under investigation promoted the growth of Rhizoctonia solani, thus indicating no resistance of this environment to this pathogen. These fungi, however, inhibited the growth of Helminthosporium solani.