scholarly journals Interaction of some fungal entomopathogens of rice pests with phyllophytic microorganisms of four rice genotypes cultivated in coastal Odisha, India

2016 ◽  
Vol 22 ◽  
pp. 75-84
Author(s):  
Biswajit Sahoo ◽  
Tushar Kanti Dangar

Interactions of six entomopathogenic fungi viz. Cordyceps (2 strains), Beauveria (1 strain) and Metarhizium (3 strains) spp. of rice leaf folder (LF, Cnaphalocrocismedinalis) with thephyllophytic (phyllospheric and phylloplanic) bacteria (n=35) and fungi (n=4) isolated at pre-flowering stages of fourcultivated rice (Oryzasativa L.) var. Lalat, Swarna, Swarna-Sub1 and Naveenwere assessed to reveal possibility of intergroup inhibition in the field. Dynamics of the phyllophytic microbes revealed that the phyllospheric bacterial population (3.59 to 4.10 log CFU/cm2) was more than those of the phylloplane (1.56 to 1.75 log CFU/cm2) of different plants. The phyllophytes of the four rice genotypes decreased in the order of Swarna-Sub1 > Swarna > Lalat > Naveen. The fungal pathogens of LF viz. C. brongniartii (TF6 and TF6-1A), B.bassiana (TF6-1B) and M. anisopliae (TF19, TF19- 3A and TF19-3B) were not inhibited by any of the phyllophytic organisms which proved that they can be applied on the canopy of the rice plants to control the pests.ECOPRINT 22: 75-84, 2015

2019 ◽  
Vol 46 (8) ◽  
pp. 743 ◽  
Author(s):  
Sarin Neang ◽  
Marjorie de Ocampo ◽  
James A. Egdane ◽  
John D. Platten ◽  
Abdelbagi M. Ismail ◽  
...  

Salt sensitivity in rice plants is associated with the accumulated amount of Na+ and Cl– in shoots and, more significantly, in photosynthetic tissues. Therefore, salt removal ability at the leaf sheath level is an important mechanism of salt tolerance. In the present study we attempted to determine whether rice leaf sheaths excluded Cl– as well as Na+, and to identify the tissues that were involved in the removal ability of both ions. In two rice genotypes, salt-tolerant FL478 and -sensitive IR29, leaf sheaths excluded Na+ and Cl– under NaCl treatment as estimated using their sheath:blade ratios. The sheath:blade ratio of Na+ but not of Cl–, was increased by NaCl treatment. Under NaCl treatment, Na+ concentration was higher in the basal leaf sheath, whereas Cl– concentration was higher in the middle and tip parts. At the tissue level, fundamental parenchyma cells of leaf sheaths retained the highest amounts of Na and Cl when treated with high amount of NaCl. These results imply that the leaf sheath potentially functions to remove excess Na+ and Cl– from xylem vessels in different locations along the axis, with the fundamental parenchyma cells of leaf sheaths being involved in over-accumulation of both Na+ and Cl–.


2010 ◽  
Vol 25 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Slavimira Draganova ◽  
Danail Takov ◽  
Danail Doychev

Bark beetles (Coleoptera: Curculionidae: Scolytinae) belong to one of the most damaging groups of forest insects and the activity of their natural enemies - pathogens, parasitoids, parasites or predators suppressing their population density, is of great importance. Biodiversity of entomopathogenic fungi on bark beetles in Bulgaria has been investigated sporadically. The aim of this preliminary study was to find, identify and study morphological characteristics of fungal entomopathogens naturally-occurring in populations of three curculionid species - Ips sexdentatus Boern, Ips typographus (L.) and Dryocoetes autographus (Ratz.). Dead pest adults were found under the bark of Pinus sylvestris and Picea abies trees collected from forests in the Maleshevska and Vitosha Mountains. Fungal pathogens were isolated into pure cultures on SDAY (Sabouraud dextrose agar with yeast extract) and were identified based on morphological characteristics both on the host and in a culture. Morphological characteristics of the isolates were studied by phenotypic methods. The fungal isolates obtained from dead adults of Ips sexdentatus, Ips typographus and D. autographus were found to belong to the species Beauveria bassiana (Bals. - Criv.) Vuillemin, Beauveria brongniartii (Saccardo) Petch and Isaria farinosa (Holmsk.) Fries (anamorph Ascomycota, Sordariomycetes: Hypocreales, Cordycipitaceae). Morphological traits of the isolates are described.


1981 ◽  
Vol 29 (2) ◽  
pp. 147-161 ◽  
Author(s):  
GOTTFRIED FRAENKEL ◽  
FAHEEMA FALLIL ◽  
K. S. KUMARASINGHE

2016 ◽  
Vol 106 (6) ◽  
pp. 809-817 ◽  
Author(s):  
M.A. Bodlah ◽  
A.-X. Zhu ◽  
X.-D. Liu

AbstractExtreme high-temperature events are the key factor to determine population dynamics of the rice leaf folder,Cnaphalocrocis medinalis(Guenée), in summer. Although we know that adult of this insect can migrate to avoid heat stress, the behavioral response of larva to high temperature is still unclear. Therefore, impacts of high temperature on behavioral traits ofC. medinalisincluding host choice, settling and folding leaf were observed. The results revealed that these behavioral traits were clearly influenced by high temperature. The larvae preferred maize leaves rather than rice and wheat at normal temperature of 27°C, but larvae experienced a higher temperature of 37 or 40°C for 4 h preferred rice leaves rather than maize and wheat. Capacity of young larvae to find host leaves or settle on the upper surface of leaves significantly reduced when they were treated by high temperature. High temperature of 40°C reduced the leaf-folding capacity of the third instar larvae, but no effects were observed on the fourth and fifth instar larvae. Short-term heat acclimation could not improve the capacity of the third instar larvae to make leaf fold under 40°C.


2019 ◽  
Vol 5 (2) ◽  
pp. 33 ◽  
Author(s):  
M. Constanza Mannino ◽  
Carla Huarte-Bonnet ◽  
Belén Davyt-Colo ◽  
Nicolás Pedrini

Entomopathogenic fungi are the only insect pathogens able to infect their host by adhesion to the surface and penetration through the cuticle. Although the possibility of fungal infection per os was described almost a century ago, there is an information gap of several decades regarding this topic, which was poorly explored due to the continuous elucidation of cuticular infection processes that lead to insect death by mycosis. Recently, with the advent of next-generation sequencing technologies, the genomes of the main entomopathogenic fungi became available, and many fungal genes potentially useful for oral infection were described. Among the entomopathogenic Hypocreales that have been sequenced, Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Cordycipitaceae) is the main candidate to explore this pathway since it has a major number of shared genes with other non-fungal pathogens that infect orally, such as Bacillus thuringiensis Berliner (Bacillales: Bacillaceae). This finding gives B. bassiana a potential advantage over other entomopathogenic fungi: the possibility to infect through both routes, oral and cuticular. In this review, we explore all known entry gates for entomopathogenic fungi, with emphasis on the infection per os. We also set out the fungal infection process in a more integral approach, as a need to exploit its full potential for insect control, considering all of its virulence factors and the conditions needed to improve its virulence against insect that might offer some resistance to the common infection through the cuticle.


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