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Stem rust, caused by Puccinia graminis f.sp. tritici, is one of the most dangerous rust diseases on wheat. Through physiological, biochemical, and molecular analysis, the relationship between the change in resistance of 15 wheat cultivars to stem rust disease and the response of 41 stem rust resistance genes (Sr,s) as well as TTKSK, TTKST, and TTTSK races was explained. Some cultivars and Sr genes, such as Gemmeiza-9, Gemmeiza-11, Sids-13, Sakha-94, Misr-1, Misr-2, Sr31, and Sr38, became susceptible to infection. Other new cultivars include Mir-3 and Sakha-95, and Sr genes 13, 37, 40, GT, and FR*2/SRTT3-SRTT3-SR10 remain resistant. Some resistance genes have been identified in these resistant cultivars: Sr2, Sr13, Sr24, Sr36, and Sr40. Sr31 was not detected in any cultivars. Reactive oxygen species such as hydrogen peroxide and superoxide, enzymes activities (catalase, peroxidase, and polyphenoloxidase), and electrolyte leakage were increased in the highly susceptible cultivars, while they decreased in the resistant ones. Anatomical characteristics such as the thickness of the epidermis, ground tissue, phloem tissue and vascular bundle diameter in the midrib were decreased in susceptible cultivars compared with resistant cultivars. Our results indicated that some races (TTKSK, TTKST, and TTTSK) appeared for the first time in Egypt and many other countries, which broke the resistant cultivars. The wheat rust breeding program must rely on land races and pyramiding genes in order to develop new resistance genes that will survive for a very long time. [ABSTRACT FROM AUTHOR]

The toxicity and repellency of some essential oils against Solenopsis invicta ant was evaluated under laboratory conditions and the infested areas (indoor and outdoor). Essential oils of orange, lemon, peppermint and basil oils were used to control ants of Solenopsis invicta using a new friendly and environmentally application method. The prepared mixtures of previous oils in Vaseline or Gel were used as droplet points under laboratory conditions and the infested areas. Based on the data collected from repellent and toxicity test, results showed that the most effective compound was that of orange oil in Vaseline and/or Gel. This compound was followed at interval with time for one week. In and out door the tested oils achieved completed elimination of ants at the treated areas. [ABSTRACT FROM AUTHOR]

Citrus reticulata and Tagetes minuta are two economic plants in Egypt. Waste branches of C. reticulate which called petit grain are used to produce petit grain mandarin oil. This process increases the mandarin producer's income with a new product instead of burning it. Also, the waste of petit grain mandarin after distillation can be used as a compost and increase the oil producing income. Using the waste of petit grain mandarin mixing with compost of 5 tons per acre increased the yield of biomass and essential oil yield of tagette oil by (10.00 and 10.77%) for the first cut of the first year and (43.10 and 57.02%) for the second year, respectively. 22 and 10 components were identified with the GCMS analysis of C. reticulate, and of T. minuta oils, respectively. Benzoic acid is the main component in C. reticulate oil with (56.45%) while Dihydrotagetone is the main component in T. minuta oil with (30.75%). Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) are two major stored product insects. Results in current study cleared that the two tested essential oils had fumigant and contact toxicity against the two tested insects and tagette oil had the strongest effect. T. castaneum is more tolerant than S. oryzae in both fumigant and contact treatments. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the development of resistance in susceptible strains of Tetranychus urticae to chemicals (Fenpyroximate, Cyhalothrin, Abamectin and Ethion) and the specific activity of Acetylcholine esterase and Glutathion- S-transferase enzymes under laboratory conditions in order to study the mechanism of resistance in T. urticae. Resistance levels to Fenpyroximate were highly variable in two generations showing high resistance in ninth and tenth generations 66.58 and 78.72 fold, respectively. The resistance to Cyhalothrin showed that selection for ten generations succeeded in building up 37.45 fold of resistance. The resistance to Abamectin increased gradually to reach it's the ten generation, represented by 140fold. The resistance to ethion of the ninth and tenth generations ranges to 71.8 and 94.1 fold, respectively. Results showed that the specific activities of AChE enzyme were significantly lower in susceptible strain. Also, significant differences were found among the compounds. The Resistance strain of Cyhalothrin of T. urticae had the highest specific activity of AChE of 2.48 and as compared with susceptible strain, 0.94 while the resistance strain for Abamectin had the lowest specific activity of AChE 1.31. Ethion and Fenpyroximate significantly decreased the activity of AChE activities 2.20 and 2.30, respectively. Data showed that GST activity was significantly higher in all the resistant strain of T. urticae than that of the susceptible strain. [ABSTRACT FROM AUTHOR]

Sugar beet crown gall is a bacterial disease caused by Agrobacterium tumefaciens remains one of the most severe diseases, which cause unlimited loss of crop in Egypt and over world. A. tumefaciens pathogen was isolated from Sugar beet infected plants and molecularly characterized by 16S rDNA sequence and Koch's postulates applied to assure the crown gall disease that causes high defects in the sugar beet yield. The pathogens' DNA was isolated, and the PCR technique based on 16S RNA was used for three isolates. The results of comparative sequencing analysis of the new races showed high identity between races YH2 and YH3, while there was high similarity between both of YH2, 3 and YH1. A phylogenetic tree was generated based on the genomic sequences of different Agrobacterium species. The genomic sequences of YH1 share close homology with the genome sequences of Agrobacterium tumefaciens. While the genome sequences of YH2 and YH3 showed high homologues to Agrobacterium rhizogenes, this data revealed that the genomic sequences of YH2 share close homology with the genome sequences of YH3, and both of them are high homologues to A. rhizogenes. While the genome sequence of YH1 is similar to both of YH2, 3 and high homologues to Agrobacterium tumefaciens. This finding reflected that the similarity of genomic sequences and conserved regions among the new races is evolutionarily conserved in the genus of Agrobacterium. Effectiveness of antimicrobial compounds on A. tumefaciens was studied In Vitro. The inhibitory effect of Bacillus subtilis on A. tumefaciens was the highest inhibition zone diameter that was recorded among all of the antimicrobial compounds that were used in the experiment in vitro. Moreover, the antibiotic streptomycin, plant extract from Hibiscus sabdariffa, Rhus sp. pomegranate peel, and nano silver have high effects on bacterial growth compared to control. [ABSTRACT FROM AUTHOR]

The present study in directed to evaluate the relative toxicity of six chemicals of different mode of action, four Acaricides (abamectin, ethion, chlorfenapyr and Cyhalothrin), one mineral oil (Nat-1) and one plant extract (black cumin) against the adult female mite, Tetranychus urticae and its predatory mite, Amblyseius fallacies using standardized method for bioassay. The effects of sublethal doses of these chemicals on some biological aspect of the mite and its predator were also evaluated. Results indicated that abamectin was the most toxic compound of LC50 value of 0.15 ppm, white black Cumin extract was the least one (47930. 18 ppm) to adult females of T. urticae, Also, results showed that abamectin was the most effective chemical on A. Fallacis while black cumin extract was the least toxic compound to adult females of A. Fallacis. The accumulated eggs deposited by the adult females of mite T. urticae, results suggested that cyhalothrin was the most effective compound on egg deposition followed by ethion and abamectin. Nat - 1 and black cumin extract had about the same effect on that character-Cyhalothrin was the most effective compound on egg hatchability, while Nat-1 and black cumin extract were the least effective in egg hatchability. Cyhalothrin and abamectin caused the highest decrease in prey egg consumption by the predator, the most effective on predator egg production and caused highly decrease in egg hatchability comparable to the control treatment - Nat - 1 and black cumin extract were the least effective compounds in prey egg consumption, predator egg production and predator egg hatchability. [ABSTRACT FROM AUTHOR]

Pelargonium graveolens is an important economic plant, so many farmers work in producing geranium essential oil, to increase their income and also increasing the national income. Distillation of geranium herb produces floral water and factories throw it as a waste water. Using stripping column Hashem Brothers for Essential oils and Aromatic Products Company produced essential oil from waste water. The waste water contains from 0.06 to 0.2 kg/ton essential oil. Citronellol is the main component is geranium stripping oil with 31.88% followed by geraniol and linalool with 22.45% and 10.10%, respectively. Geranium stripping oil and its main components (citronellol, geraniol and linalool) were evaluated as insecticides. Triboleum castaneum is more tolerant than Rhizopirtha dominica and Sitophilus oryzae in contact and fumigant experiments. All tested components had no effect on T. castaneum as contact while geranium stripping oil had the strongest effect on R. dominica and S. oryzae. All tested components had a fumigant effect against the three tested insects. After 24 h of exposure for R. dominica, linalool had the strongest effect with LC50 of (410.3 mg/L) while, citronellol had the strongest effect on T. castaneum and S. oryzae with LC50 of (628.2 and 898.9 mg/L), respectively. Citronellol also had the strongest toxicity against S. oryzae at the same time of exposure. [ABSTRACT FROM AUTHOR]

Our study was directed to evaluate the relative toxicity of eight compounds; four pesticides (abamectin, cypermthrin, etoxazole and chlorfluazuron), two mineral oils (Chemesol and Supermasrona) and two plant extracts worm wood {Chrysanthemum morifolium) and Melia azedarach against adult females of the two spotted spider mites Tetranychus urticae and its predatory insect Stethorus gilvifrons using leaf-disc dip technique. The results indicated that, abamectin was the highest toxic compound to the adult females of T. urticae, followed by chlorfluazuron, cypermethrin and etoxazole. Abamectin has a special effect to adult females of predator S. gilvifrons, followed by chlorfluazuron, cypermthrin, and etoxazole was the least toxic one. Moreover, chlorfluazuron, cypermethrin and supremasrona were the most effective compounds on egg deposition of the adult female mites and caused the highest reduction in egg deposition comparable to the control, however, Etoxazole had the least effect on egg deposition. Cypermethrin caused the highest decrease in egg hatchability on leaf discs against egg stage of the T. urticae but etoxazole and worm wood extract were the least effective ovicidal action. Abamectin and cypermethrin were the most effective chemicals that caused a decrease in prey egg consumption comparable to the control, while etoxazole had the least effect. Also, the predators egg deposited under the chemical treatment were less than that deposited under normal conditions (untreated). Etoxazole and worm wood extract were the safest compounds that allowed the predator's eggs to hatch producing the next stages necessary as biological agent that minimize prey populations. [ABSTRACT FROM AUTHOR]

The present study was conducted to determine the direct and residual effects of the five natural plant extracts, the aerial parts of Peppermint Mentha piperita, Marjoram Origanum marjorana, Mugwort Artemisia vulgaris, cloves of Clove Syzygium aromaticum and the leaves and mature fruit pods of Egyptian acacia Acacia nilotica using soxhelt extractor, against the two spotted spider mite, Tetranychus urticae Koch, at the laboratory-controlled conditions, 30±2C° and 70±5% RH. Two concentrations, 0.25% and 0.5% were utilized to study its effects on the biological aspects of T. urticae. The results confirmed the effective influence of these extracts on mite life aspects which altered and prolonged the mite life cycle and generation time, the high prolonged life cycle lasted 13.98 days and the generation period reach 15.78 days for Acacia 0.25%, followed by the rest treatments, while control recorded the short life cycle 9.33 days and located the last significant group of generation period by 10.19 days. Meanwhile, the total immature stages which treated with Acacia 0.25% elongated the time lasted to reach adult stage (8.72 days), with significant differences with the rest treatments and control except Mentha 0.25% and Artemisia 0.5%, followed by Acacia 0.50% (7.18 days). Moreover, the used extracts also achieved the high mortality percentages, reached 64.20% and 50.62% in pre-oviposition period and post-oviposition period respectively, when treated with the highest concentration of Artemisia extract. Reduction in Fecundity achieved 57.09% and 57.02% at concentrations 0.25% and 0.5% of Syzygium, respectively. [ABSTRACT FROM AUTHOR]

The present study was directed to evaluate the relative toxicity of six chemicals, three are known acaricides (abamectin, fenpyroximate, chlorfenapyr), one pyrethroid (cyhalothrin), one mineral oil (supermasrona) and one plant extract (Nigella saliva) against the adult females of two spotted spider mite Telranychus urlicae and the adult females of predatory mite Phyloseiulus persimilis using standardized method for bioassay. The results indicated that abamectin has a special position in mite chemical control or in integrated mite management because of its high toxic effect and its high toxicity index while Nigella saliva extract was the least toxic compound to adult female T. urlicae on different host plants. Supermasrona and Nigella Sative extract were the safest compounds to the adult of predatory mite P. persimilis on different host plants. Fenpyroximate has the highest selectivity index and highest selectivity ratio in spite of its low safety values on different host plants, so it can be recommended in IPM programs. [ABSTRACT FROM AUTHOR]

The present study was directed to evaluate the effects of sublethal doses of these chemicals (three are known acaricides (abamectin, fenpyroximate, chlorfenapyr), one pyrethroid (cyhalothrin), one mineral oil (supermasrona) and one plant extract (Nigella saliva) extract) on some biological aspect of the mite (Telranychus urlicae) and its predatory mite (Phyloseiulus persimilis). The study also was undertaken to determine the rate of NPK in relation to spider mite and its predatory mite. Cyhalothrin was the most effective compound tested on egg deposition of T. urlicae which is beneficial for some IPM programs, while Nigella Salive extract has the least effect on egg deposition. Cyhalothrin, Fenpyroximate and supermesrona were highly toxic compounds that caused the highest decrease in egg hatchability of T. urlicae on different host plants. Cyhalothrin and abamectin were the most effective on prey egg consumption, predator egg production and predator egg hatchability of P. persimilis, While Nigella Salive extract was the least effective compound in prey egg consumption, predator egg deposition and predator egg hatchability on different host plants. It is clear that cucumber has the highest rates of the three elements under study (NPK). [ABSTRACT FROM AUTHOR]