Potato (Solanum tuberosum), an important vegetable crop of Pakistan endures significant yield losses due to root knot nematode (Meloidogyne incognita).. Research wok was designed to identify resistant potato germplasm against RKN (Meloidogyne incognita) infection. A field trial was conducted in the research area of Department of Plant Pathology, University of Agriculture Faisalabad. Thirty six (36) potato verities/ cultivars relocated five times were sown in four years sick plot containing root knot nematode (Meloidogyne incognita) in RCBD layout. Root knot nematode reproduction and host damage was accessed by recording nematode root galls and egg mass indices, root weight, shoot weight, , number of leaves, fruit weight, rate of reproduction and final population of nematodes. Experiment revealed a considerable variation in response against Meloidogyne incognita infection among the genotype tested but none of the single cultivar was immune. FD-8-1 was used as negative control. The cultivar FD-19-2 was highly susceptible followed by SH-692 and SH-5. All other cultivars had less galling index with low fecundity rate indicating their ability to suppress the adult female reproduction. The cultivar FD-1-3 scored least number of galls and egg mass indices followed by FD-49-62, SH-339 and SH-332.

The effect of tomato seedling treated with plant growth promoting rhizobacteria (PGPR) strains viz. Azotobacter sp. (AZM1),Bacillus cereus (BCM8), B. megaterium (BMM5) individually or combined with humic acid were evaluated for controlling wilt disease caused by Fusarium oxysporum f. sp. lycopersici, plant growth, fruit quantitative and qualitative (cv. Super Strain-B) during 2010-2011 and 2011-2012 growing seasons. Under greenhouse conditions, all treatments significantly reduced area under disease progress curve (AUDPC) and increased plant height, fresh and dry weights of survival plants growing in pots infested with the causal pathogen compared with control. Combination treatments of humic acid with PGPR reduced significantly wilt incidence and increased plant height, fresh and dry weights of tomato plants comparing with the application of each of them alone. Under laboratory conditions, all PGPR strains and humic acid able to inhibited leaner growth of the causal pathogen with different degrees and PGPR strains were more active than humic acid in this respect. Under field conditions, all PGPR stains individually or combined with humic acid significantly reduced AUDPC and improved plant growth (plant height, number of branches plant -1) quantitative (number of fruits plant -1, fruit weight plant -1, fruit weight, fruit yield fed. -1, Number of fruit Kg -1) and qualitative (degree of fruit’s color, fruit diameters, firmness, fruit height, total soluble solids) parameters of tomato fruits compared with untreated plants (control) in both growing seasons. Combination treatments of humic acid with PGPR strains increase the effectiveness of them in this respect more than used alone.

Planting sterilized corn grains in soil, treated with the mold inhibitors Fix-a-tox (FAT) or Antitox Plus (AP) resulted, in cases, in dwarfed and malformed corn plants and in the development of deformed, bone-shaped and grain-free corn cobs. Moreover, treating corn grains with the mold inhibitors before storage for one month caused significant changes in some nutritional components of corn grains, i.e. proteins, aminoacids, crude fibers, moisture, fats, ash and carbohydrates. Insignificant differences in protein percetage were detected between control inoculated with Aspergillus flavus and those treated with butyl hydroxyanisole (BHA) antioxidant or FAT treatments, whereas ground clove significantly reduced protein content. In corn grains inoculated with Fusariumverticillioides, previous treatment with FAT resulted in significant reduction in the content of proline, aspartic acid, cysteine, valine, isoleucine and leucine, whereas treatment with BHA significantly reduced the content of threonine, serine, glutamic, glycine, alanine, phenylalanine and tyrosine. In Aspergillus flavus treatments, FAT significantly increased the content of methionine and threonine, whereas, aspartic acid showed 26 percentage decreases, compared to the control. Pronounced reductions in threonine, isoleucine and leucine were also detected in corn grains treated with BHA. Significant increases in fiber content were detected in inoculated corn grains treated with BHA, attaining 1.34 to 2.05-fold over that of control, respectively. Treatment with FAT and BHA led to pronounced reductions in moisture content in corn inoculated with both F. verticilloides and A. flavus trials. However, treatment with ground clove significantly increased the moisture content in A. flavus treatment. FAT treatment led to significant increase in ash and fat contents in both A. flavus and F. verticilloides treatments, whereas the other tested treatments of F. verticilloides significantly reduced ash content. Treatment with ground clove significantly reduced fat content in A. flavus treatment. All the tested materials significantly reduced carbohydrate content.

Viroids are the smallest pathogens of plants. They are the cause of serious diseases on economic plants worldwide. Prevention and detection of the pathogens are the best method to reduce the economic loss from viroid infection. During last decade, genetics and molecular biology techniques have gained an increasing presence in plant pathology research. The purpose of this review is to highlight the most upgrade molecular biology techniques that have been used and studied recently. Most relevant published reports and hand skilled techniques have presented here with emphasis on suitable Viroid detection technique should be used for Sri Lanka.

Different strains of Pleurotus ostreatus were cultivated on different agro-cellulosic wastes viz. cotton waste, wheat straw and paddy straw to determine the effect of these agro wastes on biological efficiency, carbohydrate and mineral contents including Na, K, Ca, Cu, Zn and Fe. Maximum biological efficiency was recorded on P. ostreatus (grey strain, 134.4%) and (white strain, 113.7%) on wheat straw. P. sajor-caju showed maximum biological efficiency (195.9%) on wheat straw. Maximum amount of Na was found (0.18g/100g) on P. ostreatus (grey strain) and K was found on P. sajor-caju (4.58g/100g) cultivated on paddy straw followed by wheat straw and cotton waste. P. ostreatus (white strain) cultivated on paddy straw showed maximum amount of Cu (0.0009g/100g) while maximum amount of Zn was found (0.017g/100g) on P. ostreatus (white strain). Maximum amount of Fe was found (0.008g/100g) on P. sajor-caju cultivated on cotton waste. P. sajor-caju cultivated on cotton waste showed significantly highest carbohydrate (0.079g/100g). Different strains of Pleurotus ostreatus were cultivated on different agro-cellulosic wastes viz. cotton waste, wheat straw and paddy straw to determine the effect of these agro wastes on biological efficiency, carbohydrate and mineral contents including Na, K, Ca, Cu, Zn and Fe. Maximum biological efficiency was recorded on P. ostreatus (grey strain, 134.4%) and (white strain, 113.7%) on wheat straw. P. sajor-caju showed maximum biological efficiency (195.9%) on wheat straw. Maximum amount of Na was found (0.18g/100g) on P. ostreatus (grey strain) and K was found on P. sajor-caju (4.58g/100g) cultivated on paddy straw followed by wheat straw and cotton waste. P. ostreatus (white strain) cultivated on paddy straw showed maximum amount of Cu (0.0009g/100g) while maximum amount of Zn was found (0.017g/100g) on P. ostreatus (white strain). Maximum amount of Fe was found (0.008g/100g) on P. sajor-caju cultivated on cotton waste. P. sajor-caju cultivated on cotton waste showed significantly highest carbohydrate (0.079g/100g).

Knowledge of the geographical distribution for physiologic races of Puccinia triticina and identification of leaf rust resistance genes (Lr ,s) in the recent Egyptian wheat cultivars are essential for maximizing resistance in future-bred cultivars. The aim of this study was to know the status of resistance in Egyptian wheat cultivars against wheat leaf rust and the most frequent race distributed. Infected samples were collected from five Governorates, i.e., Dakahlia, Kafr el-Sheikh, Beheira, Sharqia and Sohag comprised the wheat growing area in Egypt. These samples were isolated, purified and identified on the differential stes. Gene postulation was done using fifteen identified races on Egyptian wheat cultivars correlated with Lr genes. Thirty three races identified during three seasons 2009/2010, 2010/2011 and 2011/2012. The most frequent race was TK (10%) followed by race BB (7.58%), PK (6.55%), TT (4.82%), PT (3.79%) and MT (3.44%). Moreover, races; BB, TT and PT were present during three seasons while these races appeared in some Governorates and disappeared in other Governorates. On the other hand, the most frequently occurring gene in ten Egyptian wheat cultivars was Lr35 (70%), followed by Lr22 (60%), Lr27 (40%), Lr34 (30%), Lr19 (30%),Lr18 (10%), Lr36 (10%) and Lr46 (10%), eight out of sixteen Lr genes were not present in the tested cultivars. It is concluded that there was a good variation in Lr genes carried by wheat cultivars commercially grown in Egypt. Therefore, strategies for deploying resistance genes to prolong effective disease resistance are suggested to control wheat leaf rust disease.

The experiment was conducted at Bako Agricultural Research Center from 2008 to 2009 cropping seasons in order to evaluate the effect of sowing dates and ploughing frequency on the development of Grey Leaf Spot (GLS) on maize. The susceptible variety Phb 3253, with three sowing dates (early, optimum and late at 10 days interval) and three ploughing treatments: Minimum tillage (once), farmer’s practice (three times ploughing) and four times ploughing were used. All plots were uniformly treated with GLS infected crop residue before first ploughing. Trial was laid out in factorial arrangement in Randomized Complete Block Design (RCBD) with three replications. Among the planting dates, the highest disease severity of 7.60, 7.44 and 7.00, (1-9 scale) and Area Under Disease Progress Curve (AUDPC) 305.83, 280.1 and 280.33 were recorded in early sown minimum (conservation) tillage practices, while the lowest was with AUDPC 161.50, 196.50 and 222.67 in four times ploughed plots in 2007, 2008 and 2009 years respectively. The highest thousand seed weight and grain yield was observed in four times ploughed and in early sown plots, while the lowest thousand seed weights and grain yield were recorded in the conservation tillage practice. Four times ploughed and early sown fields had a mean yield advantage of 474.73kg (6.66%) and a total yield advantage 2020.77kg (36.23.6%) over three times ploughed and minimum tillage practices for the three seasons 2008-2009. In general higher disease severity, low thousand seed weight and grain yield were recorded for the conservation tillage compared to other practices. The overall results showed that four times ploughing result in superior maize grain yield performance compared to others as it has resulted in reducing the disease development.

All potato cultivars are susceptible to root-knot nematodes (Meloidogyne spp.) which infest the roots and induce galls on the surface and necrotic spots in the flesh tuber of potato, Solanum tuberosum. Infested tubers are unacceptable for processing and fresh market. Tubers are also putative source of dissemination of the nematode. A French nematode- resistant tetraploid potato genotype gained from ex-S. sparsipilum material hybridized with S. tuberosum in F1 and in their back cross progenies and designated as 02T.155.6 was tested and compared in the present study in Egypt as a suitable different environment. Histopathological changes and chitinase activity induced by M. incognita population, of common occurrence in Egypt, in four French tetraploid materials and two common cultivars known as nematode- resistant and susceptible potato genotypes were investigated. Hypertrophied cells were initiated in both cortical and steler regions of the roots which were then developed to abnormal xylem elements expanding into the cortex in French susceptible genotypes designated as 02T.149.6, 02T.150.54, and 02T.157.16. Nematode within the vascular tissue (stele) could induce giant cell development close to nematode heads. The largest number of such induced cells was shown by the cultivars Spunta and Diamant. The clone 02T.155.6 with putative nematode resistance demonstrated none or very little nematode development. Recently dead second stage juveniles could also indicate incompatible plant reaction to the invading nematodes in 02T.155.6. M. incognita, Giza population, resistance was generally more coherent to 02T.155.6 as demonstrated by our histological investigations but less coherent as shown by another Egyptian M. incognita population. Chitinase activity was enhanced in M. incognita (Giza)-inoculated with respect to uninoculated roots in all plants. After inoculation, such an activity generally increased more in roots of a potato genotype previously known to have resistance or relatively low numbers of both nematode galls and eggmasses than in the other tested cultivars. Peroxidase and catalase activities of nematode- inoculated with respect to uninoculated potato roots were presented and discussed.

Rice blast, a serious epidemic disease that limits grain yield worldwide is caused by fungal pathogen Magnaporthe grisea. The present investigation was carried out to identify the probable avenues of interference by different fungicides during the critical stages of infection related morphogenesis of M. grisea. Effect of six fungicides at different stages of infection related morphogenesis showed variable results like interference in conidial germination, distortion of surface structure of the spores, interference in the germ tube elongation, interference in the transfer of the cell contents from spore to appresorrium, deformity in appressorial dome, interference in the melanin deposition. We speculate the critical stages at which these fungicides may interfere. The activity of immunosuppressive drug cyclosporin A (CsA) which is a potential antifungal agent was equated with all the fungicides used. We hypothesize that the exposure of the M. grisea spore to the fungicide may lead to the formation of a cyclophilin CYP1-fungicide complex, which inactivates calcineurin and prevents calcium/ calmodulin-dependent protein phosphatase signaling and is therefore one of the target of fungicidal interference. An understanding of how fungal pathogens break the protective barrier that comprise the surface of the host plant as well as precise identification of avenues of fungicidal interference during infection related development in M. grisea will lead to novel approach for controlling plant diseases.

Lantana camara, Eucalyptus globulus, Tagetus minuta, Pyrethrum flowers and Azaddiractha indica, were evaluated against potato tuber moth damage with two checks (Diazinon 60% EC and untreated check) at Bako Agricultural Research Center in 2007/2008 and 2008/2009 cropping seasons. A total of 21 huts (cottages) were constructed from locally available materials. Inside each cottage (hut), 1m 2 bed was constructed 65 cm above the ground. Six hundred fifty (650) potato tubers were stored on the bed of each hut in two layers one over the other. The treatments were arranged in a Randomized Complete Block Design (RCBD) with three replications. Plants powder and Diazinon 60% EC were applied respectively, at the rate of 50 gm / bed and 3.5ml / bed at two months’ interval. The treatments that showed promising effects were further advanced on a large bed (2m x3m). Three thousand nine hundred (3900) potato tubers were stored on large beds and 150gm powders were used for each bed. Evaluations were made at the interval of 15 days for 7 consecutive months. Analysis of variance showed that number of potatoes infested and damaged by potato tuber moth was significantly (P0.05) lower in the Lantana camara, Eucalyptus globulus and Pyrethrum flowers than the other treatments, which are similar to standard check. From the study it can be concluded that Lantana camara, E. globulus andPyrethrum flowers can be used to protect seed potatoes from potato tuber moth damage in storage.

Plant parasitic nematodes which are highly successful parasites evolved a very specialized feeding relationship with the host plant to cause the destructive root-knot disease. They initiate their parasitic relationship with the host by releasing their secretions into root cells which in turn stimulate the root cells of the host to become specialized feeding cells which are considered as the single source of nutrients essential for the nematode's survival. The parasitism genes expressed in nematode's esophageal gland cells encode secretory proteins that are released through its stylet to direct the interactions of the nematode with its host plants.

Among two methods of Macrophomina phaseolina inoculation used for pathogenicity test, soil infestation method comparatively checked more plant growth of okra plants than seed infestation method. Minimum plant length and weight, as well as seed germination were observed by soil infestation method. Significantly maximum plant mortality and root infection was also occurred in soil infestation method. Seed germination, plant growth, plant mortality and root infection of okra plants were adversely affected with the increasing inoculum levels of M. phaseolina. Seed germination and plant growth were negatively correlated with inoculated pathogen population; whereas, plant mortality and root infection were positively correlated with the inoculum level of M. phaseolina.