Journal of Phytopathology and Pest Management (Al-Azhar University)
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Acalypha indica Linn is a potential source of root-knot nematode infestation in cultivated fields
Get PDFAcalypha indica L. is a commonly growing weed in India, which is also known as Indian Acalypha. These plants were growing as a weed in pots wherein okra was planted for experimental purpose. Infestation of the root-knot nematode, Meloidogyne incognita was observed on it. Soil and root samples were collected for analyses of nematode infestation. Roots of the infested plants were galled measuring gall index (GI) of 3-4. The population density of second stage juveniles (J2) in soil varies from 378-752/200cc soil and the roots were harboring 3876-7654 eggs/per root system. The root galling and presence of high population of nematode eggs and J2 revealed that A. indica can be a reservoir for M. incognita during non-host cropping and serve as a source of infestation to other hosts in the next cropping season. So, in the light of present findings growers are advised to be watchful for A. indica in their fields, and keep the field free from this weed to minimize the infestation of M. incognita in the next crop. Â
Impact of the resistance to Pirimicarb on the ability of the cotton aphids, Aphis gossypii Glover (Homoptera: Aphididae) in transmitting plant viruses
No full textThe present investigations were undertaken to identify the relationship between pirimicarb resistance in Aphis gossypii Glover and its transmitting cucumber mosaic virus (CMV) potency to squash plants.Data show that the percent of plants infested by mosaic virus transmitted by the dark form of cotton aphid, commonly, was higher than that inoculated by the light form. In the base line of Assiut aphid colony, virus infestation% caused by light and dark forms were 46.3 and 55.5 respectively, whereas, the infestation percentages of light and dark colored forms after one year of pirimicarb selection were 65.1 and 94.3 respectively. Data of light and dark colored forms of New Valley aphid colony, gave the same trend of Assiut aphids. The percent of plants infested by mosaic virus transmitted by the dark form of cotton aphid was higher than that inoculated by the light form. In the base line of Assiut aphid colony, virus inoculation periods in case of light and dark forms were 23.0 and 11.0 days respectively and after one year of Pirimicarb selection were 15.0 and 7.5 days respectively. The inoculation period of mosaic virus transmitted by the dark form of cotton aphid, commonly, was shorter than that of the light form. In the present study, it is clear that the ability of cotton aphid expressed as % infection of inoculated plants is resistant correlation as 64% of the differences in plant virus infestation are due to the level of pirimicarb resistant value. This finding may be attributed to the inoculation period which has a negative correlation with the pirimicarb resistance level. This negative correlation means that the more of resistance level, the less of inoculated period. The coefficient of determination was found to be 0.7 which indicates that 70% of the variability in inoculation period is due to pirimicarb resistance level. Our studies lead to the fact that the presence of the dark form of cotton aphid in the normal conditions is an alarm telling us that the aphid colony is going toward insecticide resistance subsequently, spread of plant virus diseases. Therefore, farmers must pay attention to the integrated pest management programs, without the use of chemical control methods to avoid the appearance of resistant strains (dark forms). Â
Biocontrol of cantaloupe damping-off disease caused by Fusarium semitectum by using formulations of antagonistic fungi
Get PDFoai:ojs.ppmj.net:article/2Antagonistic capability of 19 isolates of fungi isolated from rizosphere of cantaloupe plants was tested in vitro against growth of Fusarium semitectum isolate the causal pathogen of damping- off of cantaloupe. Trichoderma viride (isolate no. 17), T. harzianum (isolate no. 19) and Fusarium concolar  (isolate no.4) showed significant  percentage of inhibition against  to F. semitectum. The effect of carrier formulations of antagonistic fungi (talc based powder and rice bran) on damping-off of cantaloupe were tested under greenhouse and field conditions. In greenhouse experiments, application of antagonistic fungi with rice bran formulation two weeks before planting caused the highest percentage of survival plants in pre and post damping-off (83.33 and 75%, respectively), whereas application of talc based powder formulation significantly increased percentage of plant survival at the time of planting in pre and post damping-off (91.67 and 75%, respectively). In field experiments, application of tested formulations of antagonistic fungi to infested soil with F. semitectum two weeks before planting resulted in higher percentage of plant survival in pre and post damping-off in both teste
Do you want to bet on baits? An evaluation of Various Baits for Jackfruit Fruit Fly, Bactrocera umbrosa Fabr. (Diptera: Tephritidae)
Get PDFThe efficiency of the various baits namely: baker’s yeast, brewer’s yeast and pheromone on fruit flies, Bactrocera umbrosa Fabr. was studied under the laboratory and field conditions. In the laboratory, 120 starved fruit flies were subjected to experiment in a choice test. The field trapping experiment was conducted at the Pomology Experimental Station of theVisayasStateUniversity, Visca,BaybayCity,Leyte using an improvised yellow trap to test the effectiveness of the yeast-based baits and pheromone as baits to the insect under field condition. The laboratory assay experiment showed that pheromone attracts the most number of flies compared to other treatments. However, only males are attracted to pheromone. It is followed by the baker’s and brewer’s yeast which attracted both female and male flies. In field trapping, results showed that pheromone, and yeast-based baits were able to trap flies. Nonetheless, pheromone significantly trapped the number of flies. Thus, pheromone is the most effective amongst treatments while yeast-based baits showed potential results and merit further study to optimize its use
Control of root rot and wilt disease complex of some evergreen fruit transplants by using plant growth promoting rhizobacteria in the New Valley Governorate, Egypt
Get PDFRoot rot and wilt disease complex were detected in several guava, lemon and olive transplant nurseries and new orchards at El-Kharga, Baris, ballet, El-Dakhla and El-Farafrah districts, the New Valley Governorate, Egypt. The average percentage of root rot/wilt incidence and severity in surveying districts were 37.7, 26.5%in guava; 41.7, 34.0%;in lemon and 41.2, 29.5% in olive transplants, respectively. The most frequently isolated fungi from rotted roots of the guava, lemon and olive transplants were Fusarium oxysporum, F. solani, Macrophomina phaseolina and Rhizoctonia solani. In pathogenicity tests, all the tested fungi were pathogenic to guava, lemon and olive transplants. The effect of plant growth promoting rhizobacteria (PGPR) individually and/or mixed when used as a soil drench treatment were varied in reducing root rot/ wilt incidence and severity under greenhouse conditions compared with control. The mixed of PGPR gave the highest protection against root rot/wilt diseases compared with the use of PGPR individually. All treatments significantly increased plant height (cm), number of leaves transplanting-1, leaf area (cm2), fresh and dry weights transplanting-1 (gm) compared with control treatment
Relationships between selectivity of Aphis gossypii Glover and Aphis craccivora Koch to sucrose and maltose and their resistance to pirimicarb
Get PDFPirimicarb LC50 base line was determined by the dipping technique in successive concentrations of the trade form of pirimicarb in water. The LC25 was used for the selection every month through a year. In case of 10 sucrose solutions versus water, 8 counts indicated that aphids did not prefer the sucrose solution. After 6 hours the cotton aphid could not discriminate between the sugar solution and water. The discrimination between sugars was enhanced by adding 10% maltose. It was observed that the dark forms of the cotton aphid, A. gossypii and light forms of the cowpea aphid, A. craccivora attracted to the higher sucrose solution than the other forms. The cotton aphid, A. gossypii has a light color as the basic color, transforming under reversible condition to dark green, whereas, the basic color of cowpea aphid, A. craccivora usually black in color, transforming under stress to light brownish. This reversed evidence explained the differences in response towards sugar of the two aphid species.It may be concluded that the dark morphs of A. gossypii, and light morphs of A. craccivora which are considered pirimicarb resistant preferred high sugar levels. In other meaning, the present study proved that dark morphs of the cotton aphid and light forms of the cowpea aphid were resistant to pirimicarb and this resistance was positively correlated with the levels of sugars in the plants. Therefore, plant breeders are requested to pay efforts in screening process of resistant plants to produce plants with low sugar contents to increase the effectiveness of pirimicarb against both species of aphids. Â
Effect of seed borne pathogens on germination of some vegetable seeds
Get PDFSeed borne infection and germination of seeds of 7 vegetables viz. amaranth, red amaranth, spinach, okra, cucumber, tomato and eggplant were tested and 11 fungi were detected which were Alternaria spp., Aspergillus flavus, Aspergillus niger, Phomopsis vexans, Curvularia spp., Fusarium spp., Penicillium spp., Rhizopus spp., Colletotrichum dematium, Macrophomina phaseolina and Cladosporium spp. Six fungi were detected in amaranth, six fungi in red amaranth, four fungi in spinach, six fungi in okra, four fungi in cucumber, four fungi in tomato and five fungi in eggplant seeds. The highest total seed borne fungal infection was found in okra (26.75%), while the lowest was found in cucumber (13.50%). The highest percent germination was recorded in cucumber (87%), while the lowest in okra (49.5%). Maximum germination failure was recorded in okra (50.5%) and the lowest was recorded in cucumber (13%). Maximum normal seedlings were recorded in cucumber (77%) and the minimum was in okra (45%). The highest number of abnormal seedlings was found in okra (4%) and lowest in eggplant (2%). The highest number of diseased seedlings was found in okra (9%) and lowest in cucumber (2%). Maximum numbers of dead seeds were found in red amaranth (48%), while lowest in cucumber (18%). Among the vegetable seeds, highest seedling vigor index was encountered in cucumber (2150.5) and lowest in red amaranth (275.95).Â
Influence of certain carbon and nitrogen sources on antagonistic potentiality of Trichoderma harzianum and Bacillus subtillus against Botrytis allii the incitant of onion neck rot
Get PDFGliotoxin Fermentation Agar (GFA) Medium and Nutrient Glucose Agar   (NGA) medium with different carbon and nitrogen sources were used to study the impact of carbon and nitrogen sources on Trichoderma harzianum Rifai and Bacillus subtillus Cohn antagonistic efficiency against growth of Botrytis allii Munn. Results indicated that Trichoderma harzianum gave the highest inhibition % in growth of Botrytis allii when Sucrose was used as a carbon source while the lowest values of inhibition% were appeared by application of Mannitol as a carbon source. Trichoderma harzianum gave the highest inhibition% in growth of B.allii when use Potassium nitrate  as a nitrogen source while the lowest values of inhibition% in growth of B.allii were obtained by application of Beef extract as a nitrogen source. Results showed also that Bacillus subtillus gave the highest inhibition% in growth of B.allii when Mannitol was used as a carbon source while the lowest values of inhibition% in growth of B.allii were appeared by application of Sucrose as a carbon source. Bacillus subtillus gave the highest inhibition% in growth of B.allii when use Glutamic acid as a nitrogen source while the lowest values of inhibition% in growth of B.allii were appeared by application of Tryptophan as a nitrogen source.Â
Simmondsin as natural alternative fungicide in squash root rot disease
Get PDFJojoba (Simmondsia chinensis) meal was extracted with acetone, isopropanol, boiling distilled water and methanol to obtain simmondsin. Simmondsin was tested against Squash root rot disease at four concentrations (10, 20, 30 and 40 mg/ml) using the radial mycelia growth under greenhouse and field conditions. Rhizoctonia solani (Kuhn) and Fusarium solani (Mart.) were isolated from naturally infected squash roots collected from different localities in Qalubia Governorate. Evaluation simmondsin extracts revealed that acetone was the most effective as it prevented the myceial growth of F. solani and R. solani at 40 mg/ml, followed by isopropanol, boiling water and methanol in vitro. All extracts even at concentration 10 mg/ml had little effect and failed to produce a considerable reduction in growth of the tested fungi. Squash Eskandrany seeds were treated with simmondsin extracts before sowing in artificially infested soil with F. solani and R. solani (pot experiments) or soil naturally infected (epidemic soil) by the tested pathogenic fungi (field experiments) resulted in significant reduction in both damping- off and dead plant (resulted from infection by root-rot disease) compared with untreated seeds. Also, both acetone and isopropanol extract were more efficient in reducing infection by damping-off and root-rot than boiling distilled water and methanol. While, squash seeds treated with tested simmondsin extract significantly increased fruit yield/plot compared with untreated seeds. Also, all tested simmondsin extracts significant increased plant survival.Squash eskandrany seeds were treated with simmondsin extracts before sowing in artificially infested soil with F. solani and R. solani (pot experiments) or soil naturally infected (epidemic soil) by tested pathogenic fungi (field experience) resulted insignificant reduction in both damping- off and dead plant (resulted from infection by root-rot disease) compared with untreated seeds. Also, both Acetone and Isopropanol were more efficient reducing infection by damping-off and root-rot the high concentration 40 mg/ml than Boiling water and Methanol. On the other hand, squash seeds treated with tested simmondsin extract significantly increased fruit yield/plot compared with untreated seeds. Also, all tested simmondsin extracts significant increased plant survival
Heat and freezing pre-thermal treatments as a means of freeing potatoes from mosaic virus and its effects on potato plants quality characters
Get PDFThe aim of the study was to control of potato mosaic virus by using hot-air, hot-water and freezing as a physical pre-thermal treatments. Infected tubers of Lady Rosetta and Mondial potato (Solanum tuberosum L.) cultivars were treated by hot-air and hot-water treatments at 55± 2 ÌŠ C and freezing treatment at -18±2 ÌŠ C for 1, 2, 3 and 4 hours. Hot-air and freezing treatments showed complete elimination of mosaic virus from treated tubers. Hot-water treatment caused tuber damage at different exposure times. In this respect, hot-air treatment at 55± 2 ÌŠ C and freezing treatment at -18±2 ÌŠ C for two hours gave the best results of eliminating the virus from tubers and did not affect on economic characters of potato cultivars.Â