scholarly journals Field study on the effect of the Entomopathogenic Fungi Beauveria bassiana (Bals.) Vuil. On the cotton leaf worm Spodoptera littoralis (Boisd.) on potato plant.

2008 ◽  
Vol 2 (1) ◽  
pp. 24-32
Author(s):  
Sh. H. AL-Obaidi ◽  
L. K. AL-Ani ◽  
W. A. Hussain

A field study were conducted to evaluate the efficacy of the entomopathogenic fungi Beauveria bassiana as abiocontrol agent for the cotton leaf worm Spodoptera littoralis infesting potato plants. Results indicated that soil treatment of the entomopathogenic fungi significantly reduced the percentage of plant infestation to 64.3, 60.7 % after 14, 21 days. Results of the infection intensity also significantly reduced in treatment of entomopathogenic fungi in soil to 18.7, 9.9 pore/leaf after 14, 21 days of treatment.The results revealed the higher efficiency of entomopathogenic fungi on plant yield, it become 633.3 gm in entomopathogenic fungi in soil treatment.

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Funda Şahin ◽  
Yusuf Yanar

Abstract Background Pathogenicity of the entomopathogenic fungi (EPF), isolated from soil samples collected from Ordu Province, Turkey, was evaluated on the second-instar larvae of the cotton leaf worm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions. Results Firstly, single-concentration response tests were conducted in order to determine the efficacy of the 64 isolates on S. littoralis larvae at the concentration of 1 × 108 conidia/ml. The five isolates displaying the highest mortality rates in single-concentration response tests, ORU-50, ORM-40, ORP-13, ORP-27 and ORM-48 (which included Beauveria bassiana, Metarhizium brunneum and Clonostachys rogersoniana), were subjected to concentration–response tests at the concentrations of 1 × 105–1 × 109 conidia/ml. The lowest LC50 and LC90 values were recorded at ORP-27 with 1.68 × 107 and 4.60 × 108 conidia/ml, respectively, followed by ORP-13 and ORM-40. Conclusions Accordingly, it was found that M. brunneum isolates were more effective than B. bassiana and C. rogersoniana against S. littoralis larvae. ORP-27, ORP-13 and ORM-40 of M. brunneum isolates can be a potential biological control agent used against S. littoralis larvae.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Besma Hamrouni Assadi ◽  
Sabrine Chouikhi ◽  
Refki Ettaib ◽  
Naima Boughalleb M’hamdi ◽  
Mohamed Sadok Belkadhi

Abstract Background The misuse of chemical insecticides has developed the phenomenon of habituation in the whitefly Bemisia tabaci (Gennadius) causing enormous economic losses under geothermal greenhouses in southern Tunisia. Results In order to develop means of biological control appropriate to the conditions of southern Tunisia, the efficacy of the native strain of the predator Nesidiocoris tenuis Reuter (Hemiptera: Miridae) and two entomopathogenic fungi (EPF) Beauveria bassiana and Lecanicillium muscarium was tested against Bemisia tabaci (Gennadius). Indeed, the introduction of N. tenuis in doses of 1, 2, 3, or 4 nymphs per tobacco plant infested by the whitefly led to highly significant reduction in the population of B. tabaci, than the control devoid of predator. The efficacy of N. tenuis was very high against nymphs and adults of B. tabaci at all doses per plant with a rate of 98%. Likewise, B. bassiana and L. muscarium, compared to an untreated control, showed a very significant efficacy against larvae and adults of B. tabaci. In addition, the number of live nymphs of N. tenuis treated directly or introduced on nymphs of B. tabaci treated with the EPF remained relatively high, exceeding 24.8 nymphs per cage compared to the control (28.6). Conclusions It can be concluded that the native strain of N. tenuis and the EPF tested separately were effective against B. tabaci. Their combined use appears to be possible.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Muhammad Shehzad ◽  
Muhammad Tariq ◽  
Tariq Mukhtar ◽  
Asim Gulzar

Abstract Background The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a noxious pest of cruciferous crops all over the world causing serious economic damage. Management of insect pest generally depends on chemical control; however, due to development of resistance against all types of insecticides, alternative approaches especially utilization of a microbial agent is inevitable. Results Potential of 2 entomopathogenic fungi (EPF), viz., Beauveria bassiana and Metarhizium anisopliae, was evaluated against 2nd and 3rd larval instars of P. xylostella by adopting leaf dip and direct spraying methods under laboratory conditions. Significant mortality rate was achieved by each fungus under adopted methodologies. However, B. bassiana was found to be more effective in both conditions than M. anisopliae. Highest mean corrected mortality (77.80%) was recorded, when spores of B. bassiana were sprayed on the 2nd instar larvae (LC50=1.78×104/ml) after the 6th day of treatment. Similarly, incase of M. anisopliae LC50 for the 2nd instar at the same methodology was 2.78×104/ml with a mortality percentage of 70.0%. Offspring sex ratio was non-significantly related to treatment concentration and methodology, except for the control. Conclusion Beauveria bassiana and M. anisopliae had potential to suppress P. xylostella infestations when applied appropriately. Present findings suggested that B. bassiana and M. anisopliae when sprayed on immatures of host insect had more effect as compared to leaf dip procedure. Furthermore, no significant effect of concentrations was observed on sex ratio.


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