Journal of Phytopathology and Pest Management (Al-Azhar University)
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Evaluation of certain antagonistic fungal species for biological control of faba bean wilt disease incited by Fusarium oxysporum
Get PDFFusarium wilt incited by Fusarium oxysporum Schlecht. causes a remarkable economic losses in faba bean (Vicia faba L.) growing areas. In this study, fourteen isolates of F. oxysporum were isolated from the diseased faba bean plants, showing wilt symptoms, obtained from different localities in Assiut governorate. The isolates proved to be pathogenic on Masr-1 faba bean cultivar under greenhouse conditions. The effectiveness of five antagonistic fungal species (Trichoderma harzianum Rifai., Trichoderma viride Pers., Gliocladium roseum Bainier, Gliocladium catenulatum Gilman & Abbott and Saccharomyces cerevisiae) in growth inhibition of the pathogen in vitro as well as controlling the disease in greenhouse were evaluated. All tested antagonistic fungi were able to inhibit the growth of F. oxysporum in dual culture, significantly, as compared with control. Results also indicate that F. oxysporum suppressed strongly by coating seeds of faba bean by T. harzianum, T. viride, G. roseum, G. catenulatum and S. cerevisiae before sowing in the soil. Furthermore, the lowest percentages of Fusarium wilt severity were recorded by T. viride and G. roseum which reduced disease incidence to 22.25 % and 25.25% respectively, compared with 75.50 % in untreated seeds. It could be suggested that such antagonistic fungal species might be promising as alternatives for controlling faba bean wilt caused by Fusarium oxysporum
Evaluation of certain Nitrogen-Fixing Bacteria against Fusarium spp. infected peanut
Get PDFIn this study, the inhibition of soil borne pathogenic fungi Fusarium spp. that cause root and pod rot diseases in peanut (Arachis hypogaea) was investigated by using soil-isolated Plant Growth Promoting Rhizobacteria (PGPR), (Azotobacter and Azospirillum) and root-nodule Brady- Rhizobium as biological agents. Twenty seven isolates of Azotobacter  and 26 isolates of Azospirillum obtained from rhizosphere of peanut plants, The efficiency of the nitrogenase activity was estimated and the best four Azotobacter isolates including (A3, A7, A11, and A20) and three Azospirillum isolates including (AZ2, AZ14 and AZ18) were selected as the most efficient in nitrogenase activity. These isolates were subjected to test their ability in solubilizing zinc and phosphate and their strength in direct antagonism. The isolates A7 and Az18 were more efficient in solubilizing Phosphate and zinc. Azospirillum sp. AZ18, Azotobacter sp. A7 and Brady-Rhizobium sp. B-Rh1 achieved the highest reduction percentage in mycelia linear growth of pathogenic fungi in vitro. Under greenhouse conditions, Azotobacter sp. A7 recorded the highest disease reduction percentage of peanut root rot (44.38 %). Furthermore, Brady-Rhizobium sp. B-Rh1 recorded the highest disease reduction of peanut pod rot (50.6%) followed by Azotobacter sp. A7 (47.62%). In addition, our results showed that inoculation with the tested nitrogen fixing bacteria gave remarkable increase in the yield parameters of peanut plants such as number and weight of pods and increased the vegetative biomass overall
Changes in chlorophyll, phenols, sugars and mineral contents of cucumber plants infected with cucumber mosaic virus
Get PDFBiochemical studies were made to monitor the relationship of chemical components and development of resistance in cucumber plants against Cucumber mosaic virus (CMV). Total soluble phenols, soluble sugars, chlorophyll and mineral nutrients; Potassium, Magnesium, Sodium and Lead were compared among resistant and susceptible varieties. Different metabolites showed different trends among diseased and healthy plants from resistant and susceptible groups of varieties. The phenolic and Magnesium contents increased in the inoculated plants of both susceptible and resistant genotypes. In resistant variety, rise in magnesium concentration in inoculated plants was less as compared to that of inoculated plants of the susceptible varieties. However, the chlorophyll, sugars, potassium were reduced in the inoculated plants of both reaction resistant and susceptible reaction groups. Plants from susceptible group presented a lower of level of nutrients as compared to un-inoculated ones whereas; the changes in sodium contents were not showing any relation to resistance mechanism
Toxicity and field persistence of thiamethoxam and dinotefuran against cabbage aphid, Brevicoryne brassica L. (Homoptera: Aphididae) under laboratory and field conditions
Get PDFCabbage aphid, Brevicoryne brassica L. is one of the most destructive and economically important insect pests of canola (Brassica napus L.) worldwide including Egypt. Few information is available on the effect of neonicotinoid insecticides (thiamethoxam and dinotefuran) against cabbage aphid on canola fields in Egypt, particularly in Assiut Governorate. Thus, this study was carried out to evaluate the toxicity and field persistence of thiamethoxam and dinotefuran against cabbage aphid under laboratory and field conditions. Under laboratory condition, thiamethoxam was showed high toxic effect against adult field strain of cabbage aphid with LC50 values, 84.10, 6.60 and 3.21 mg/L after 24, 48 and 72 hrs post treatment, respectively. In addition, dinotefuran also exhibited toxic effect against this pest but less than thiamethoxam where the LC50 values were 300.50, 43.85 and 6.74 mgL-1, respectively after the periods of exposure. Based on the relative potency values, thiamethoxam was more effective than dinotefuran with 3.6, 6.6 and 2.1 fold after the periods of exposure. Under field condition, both thiamethoxam and dinotefuran exhibited efficiency against cabbage aphid population on canola plants after one, three, seven, fifteen and twenty-one days of treatments but thiamethoxam was more efficient than dinotefuran. Cabbage aphid reduction percent were 62.07, 89.80, 96.02, 96.59 and 94.55% for thiamethoxam and 8.58, 65.63, 86.77, 93.92 and 71.18% for dinotefuran after periods of exposure. The obtained data from this study indicated that thiamethoxam have a high toxicity effect against cabbage aphid under laboratory and field conditions. Based on our results, we suggest using thiamethoxam for cabbage aphid control in canola fields in Assiut Governorate, however more trails are needed about which in other Egyptian Governorates
Effect of soil amendment with activated yeasts on controlling Fusarium and Verticillium wilt and growth characters of pepper
Get PDFWilt disease of pepper caused by Fusarium oxysporum f. sp. capsici (FOC) and Verticillium dahliae (VD) is serious worldwide disease and cause great problems in all pepper production areas of the world. Six isolates of FOC and three isolates of VD were obtained from naturally diseased pepper plants from different localities of Assiut Governorate, Egypt. These isolates had the ability to cause wilt symptoms either as a vascular browning or as a foliar yellowing with different degrees. Also, there was correlation between the degree of vascular browning and foliar yellowing which has occurred with the same tested isolate. The efficacy of activated yeasts of Saccharomycess cerevisiae (dry and soft) for controlling the wilt disease caused by FOC and VD was studied. In greenhouse experiments, application of dry and soft activated yeast at the concentrations of 4, 6 and 8 gL-1 into infested soil with FOC and VD one and three weeks after seedlings transplanting significantly reduced the disease severity of Fusarium and Verticillium wilts. Likewise, concentration of 6 gL-1 of yeasts was the most effective ones. Data indicated that the soft yeast treatment exhibited the highest reduction in the disease severity compared to other treatments in both tested seasons (2014 and 2015). Yeasts treatments significantly enhanced stem length and diameter of pepper plants compared to untreated plants.Â
Implementing of RCPs scenarios to estimate the population density of parlatoria date scale insect, Parlatoria blanchardii (Targioni-Tozzetti) (Hemiptera: Diaspididae) infesting date palm trees in Luxor Governorate, Egypt
Get PDFThe present work was carried out to study the effect of some climatic factors on the population density of the white date palm scale insect, Parlatoria blanchardii on date palm trees during three time series (2011-2040, 2041-2070 and 2071-2100) under four Representative Concentration Pathway (RCP) scenarios (2.6, 4.5, 6.0 and 8.5) as compared with the current population of the pest (average of population density from 2009 to 2013 years) at Esna district, Luxor Governorate, Egypt. Results showed that monthly observations of total population of P. blanchardii had three to four peaks of seasonal activity per year. The mean minimum temperature was the most effective variable in population changes by 18.9, 20.9 and 19.9% for nymphs, adult females and total population of P. blanchardii during the base year data, respectively. The obtained results revealed the all expected values for number of nymphs, adult females and total population of insect during the all different time series under all different RCPs scenarios were smaller in comparison to the current population of insect. Expected total population of insect will be smaller at time series of (2071-2100) as compared with the two time series of (2041-2070) and (2011-2040) under the scenarios of (RCP 4.5, RCP 6 and RCP 8.5). Also, the time series of (2071-2100) exhibited the highest percentage of decreasing of the number of nymphs, adult females and total population with an average of (25.84, 23.76 and 24.91%) as compared to the time series of 2040-2071 (24.68, 22.44 and 23.68%) and the time series of 2011-2040 (10.43, 10.17 and 10.31%), respectively. Furthermore, the RCP 8.5 scenario exhibit the highest population density of nymphs, adult females and total population P. blanchardii and the lowest decreasing percentage of population density of P. blanchardii as compared with the different RCPs during all different time series.Â
Efficacy of emamectin benzoate, pyridalyl and methoxyfenozide on pomegranate butterfly, Virachola livia (Klug) (Lepidoptera: Lycanidae) in cultivated and reclaimed lands
Get PDFThe pomegranate butterfly, Virachola livia (Klug) (Lepidoptera: Lycanidae), is one of the most important pests in Egypt. Under pomegranate field conditions, the study was conducted from 2012 to 2013 to compare the efficacy of methoxyfenozide, pyridalyl and emamectin benzoate against pomegranate butterfly in cultivated and reclaimed lands at Assiut Governorate, Egypt. These insecticides demonstrated a significant low infestation of the pomegranate butterfly during 2012 and 2013 seasons compared to control field. Emamectin benzoate and pyridalyl were found to be highly effective for controlling V. livia with an average infestation of 0.33- 4.33% and 1.00- 6.67% compared to methoxyfenozide (0.33- 17.67%) in both cultivated and reclaimed lands, respectively. Data indicated that, the infestation was higher in the cultivated land than reclaimed land during 2012 and 2013 seasons. The change in temperature and relative humidity may affect the susceptibility of pomegranate fruits to the infestation by V. livia. In addition, results showed that all pomegranate trees under treated field had a significant increase in the average weight fruits by about 70-90% compared to control field. Methoxyfenozide, pyridalyl and emamectin benzoate can be considered as promising candidates to control the pomegranate butterfly, V. livia infestation in both cultivated and reclaimed lands
Impact of planting dates and some weather factors on population fluctuation and occurrence percentage of aphids and thrips on wheat crop in Egypt
Get PDFThree planting dates of wheat (Nov., 15th, Dec., 1st and Dec., 15th ) were evaluated during 2012/ 2013 and 2013/2014 seasons at Al Ziton village, Beni-Suief Governorate to determine their effect on the population fluctuation of aphids; Rhopalosiphum padi, Schizaphis graminum, Rhopalosiphum maidis and Sitobion (Macrosiphum) avenae and thrips; Thrips tabaci. Results indicated that planting of wheat seeds in the second planting date (Dec., 1st) led to slight infestation of aphids and thrips with mean numbers of 15.52 and 5.74 individuals /10 tillers, for the two seasons. The population fluctuation of aphids and thrips were affected by delaying planting date, as the wheat plants planted at the early planting date (Nov., 15th) were found to be infested by a little numbers of aphids in the first inspection. On the contrary, the infestation of aphids postponed for 8 and 2 weeks & 8 and 6 weeks in the second and third planting dates in the two studied seasons, respectively. On the other hand, the infestation of thrips postponed for 3 & 1 weeks and 6 & 4 weeks in the second and third planting dates in the two seasons, respectively. The highest infestation rate of aphids on wheat plants were recorded at the last period of growth (ear head formation) in the three tested planting dates as the occurrence percent were 48.57, 87.55 and 76.06 % for the three planting dates, in the first season and were 92.94, 89.02 and 88.71 % in the second season. The highest infestation rate of thrips occurred during tillering stage in the 1st and 2nd planting dates, as occurrence percent were 76.58 and 78.69 % in the first season and 91.09 & 86.67 % in the second season. On the other hand, the highest infestation rate of thrips at the 3rd planting date were recorded during the ear head formation, showing occurrence percent of 94.84 and 91.15 % in the two seasons, respectively. The population density of aphids and thrips were greatly influenced according to the change in weather factors. The combined effect of temperature and relative humidity on the population density of aphids on wheat plants were 20.44, 37.53 and 30.12 for the three tested planting dates, in the first season and were 27.39, 25.65 and 25.81 % in the second seasons, respectively. The combined effect of two climatic factors together on the population density thrips  decreased by delaying planting date of wheat, as E.V.% were 90.52, 35.04 and 28.34 % to the three tested planting dates in the first season and 54.68, 51.28 and 31.04 in the second season, respectively.Â
Effect of the Bio-agents (Bacillus megaterium and Trichoderma album) on Citrus Nematode (Tylenchulus semipenetrans) Infecting Baladi orange and
Get PDFThe effect of two commercial compounds namely Bioarc TM (Bacillus megaterium) and Biozeid TM (Trichoderma album) at different rates against Tylenchulus semipenetrans was examined under laboratory and greenhouse conditions. In laboratory experiment, both compounds Bioarc and Biozeid as bio-control agents found to be highly nematostatic agents against J2 of T. semipenetrans. The rates of 20, 25 and 30g/l gave more than 60% J2 mortality after 72h exposure time. The highest effect was achieved at 30 g/l whereas, Bioarc (90.5 %) exhibited the highest effect followed by Biozeid (88.3%) at 30g/l after 72h exposure time. In greenhouse experiment, the bio-agents were evaluated at rates of 20, 25 and 30 g/l compared to nematicide Nemathorin 10% G at recommended dose (12.5 kg/ feddan) on the development of T. semipenetrans infecting Baladi orange and Lime seedlings. Results showed significant differences between the tested rates of both bio-agents. At the higher rate (30.0g/l), Bioarc (89.0, 89.5%; 76.6, 82.9%) was found to be more effective than Biozeid (88.3, 89.0%; 72.0, 77.9%) in reducing number of J2/100g soil and females/g root of Baladi orange and Lime infected with T. semipenetrans respectively. Moreover, both Bioarc and Biozeid at 30.0g/l significantly increased plant growth of Baladi orange and Lime infected with T. semipenetrans
Management of Cabbage Aphid, Brevicoryne brassicae L. on Canola Crop Using Neonicotinoids Seed Treatment and Salicylic Acid
Get PDFCabbage aphid, Brevicoryne brassicae L. is one of the most important pests on canola worldwide and in Egypt. Field experiments were conducted in the Faculty of Agriculture Farm, Suez Canal University, Ismailia Governorate during 2012/13 and 2013/14 seasons. The efficacy of neonicotinoids seed treatment and spraying salicylic acid (SA) alone or in combination against B. brassicae and their impact on canola yield were investigated. Results showed that canola seeds treated with Gaucho 70% WS, Cruiser70% WS and Actara 25% WG were not effective for managing of B. brassicae in the late of growing season from 15th week to 21st week. However, SA application showed significant difference in reduction of infestation compared to control. Data revealed that seed treatment with neonicotinoid insecticides followed by foliar application with SA was associated with enhanced resistance against B. brassicae. Moreover, results showed relatively increase in seed yield/plant (g) and yield/fed. (kg) in this treatment than neonicotinoid insecticides seed treatment alone, or SA alone and control.Â