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Efficiency of Three Bacterial Strains Against Tetranychus urticae Koch (Acari: Tetranychidae) Under Laboratory Conditions
2021
Heba Emam
This study was conducted to evaluate the efficiency of three bacterial strains Pseudomonas aeruginosa, Bacillus subtilis and Lysinibacillus spaericus against adult females of Tetranychus urticae Koch using spraying and dipping techniques with concentrations (101, 103, 105, 107 cfu. ml-1). The mortality percentages were calculated and numbers of each stages resulting from the live treated females were recorded. The symptoms that appear on treated female's mites as a result of death under laboratory conditions were recorded and photographed. The results revealed that, P. aeruginosa caused the highest mortality percentage of adult females T. urticae 100% after 72h at concentration 107 cfu. ml-1 by spraying application. Whereas the mortality percentage which recorded by the dipping technique was 54.58±1.71. B. subtilis also, was recorded increased the average mortality percentage of female T. urticae as it reached 73.33±2.67 in spraying technique compared 41.25±2.08 in dipping technique. While in L. spaericus recorded 62.08±3.41 mortality (%) in spraying technique but at dipping technique the mortality was 27.50±1.61. A sharp decrease was shown in number of stages resulting from lived treated females of T. urticae with P. aeruginosa by four concentrations 101, 103, 105 and 107 by using spraying technique and the life cycle was stopped at the larval stage only at concentration 101 and were not changed into the nymphal stage. While with dipping technique a slight increase in the average number of stages resulting from the adult living females treated with the previously aforementioned concentrations of bacteria P. aeruginosa. The present study cleared that application of bacteria strains on T. urticae adult females either by spraying or dipping techniques lead to some deformations such as, swelling of the body, then fluids exit followed by complete dryness of the body and forward protrusion of the podosoma region and finally death of the adult females
Show more [+] Less [-]EFFECT OF ABIOTIC AND BIOTIC TREATMENTS ON BACTERIAL ANGULAR LEAF SPOT AND PHENOLIC COMPOUNDS OF CUCUMBER
2007
S Mahmoud
Bacterial angular leaf spot disease caused by Pseudomonas syringae pv. lachrymans is one of the most important foliage disease of cucumber. The present work was planned to control the dis-ease using six inducers i.e. salicylic acid, cobalt sulphate, di-basic potassium phosphate, lithium chloride, potassium silicate and tri-potassium phosphate, in addition two bioagents named Pseu-domonas fluorescens and Bacillus subtilis were applied as foliar treatments to induce systemic resistance in cucumber plants against bacterial angular leaf spot disease. The most effective in-ducers were salicylic acid, dibasic potassium phosphate and lithium chloride, respectively. On the other hand, Bacillus subtilis was least effective one followed by potassium silicate and Ps. fluo-rescens, respectively. While, tri-potassium phos-phate, cobalt sulphate were moderate in this re-spect. Efficacy of used inducers prolonged about till six weeks after treatment.The inducers were shown to increase phenolic compounds of cucumber leaves, whereas after two weeks of treatment up to six weeks, free and total phenol in the treated plants showed higher amounts than those in the untreated ones. Another trend was obtained with conjugated phenol. A positive correlation had been noticed between ef-ficacy of inducers and accumulated amounts of free and total phenol in cucumber leaves, i.e. the higher inducer efficacy the higher free and total phenol accumulation.
Show more [+] Less [-]Fermentation of milk permeate by some proteolytic bacteria for protease production
1997
Ali, A.A. | Roushdy, I.M. (Ain-Shams Univ., Cairo (Egypt). Faculty of Agriculture)