Alternaria alternata strain VLH1: a potential entomopathogenic fungus native to North Western Indian Himalayas

Egyptian Journal of Biological Pest Control

Research

B. Jeevan¹  Krishna Kant Mishra¹  Arunava Pattanayak¹  Amit Umesh Paschapur¹  Lakshmi Kant¹  Ashish Kumar Singh¹  H. Rajashekara¹  Johnson Stanley²  A. R. N. S. Subbanna³  Prasanna S. Koti⁴ 

[1] Crop Protection Section, ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan (VPKAS), 263601, Almora, Uttarakhand, India;ICAR-Indian Institute of Millets Research, 500030, Rajendranagar, Hyderabad, Telangana State, India;ICAR-Indian Institute of Oil Palm Research, 534450, Pedavegi, East Godavari, Andhra Pradesh, India;The University of Trans-Disciplinary Health Sciences and Technology, 560064, Bengaluru, Karnataka, India;

关键词: Alternaria alternata;    Hemipteran insects;    Chitinolytic activity;    Nutritional physiology indices;    Indian Himalayas;   

DOI  :  10.1186/s41938-022-00637-0

 received in 2022-08-23, accepted in 2022-11-29,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundThe inadvertent observation of a substantial population reduction of greenhouse whiteflies infecting Salvia divinorum plants grown in a polyhouse sparked a flurry of inquiries on the cause of the population decline. The entomopathogenic fungus (EPF) (Alternaria alternata strain VLH1) infecting greenhouse whitefly on S. divinorum plants was isolated and morphologically and molecularly characterised using multilocus sequence typing.ResultsThe fungus was found to be highly virulent against sucking pests; with LC50 values ranging from 1.7 × 104 to 2.5 × 106 spores per ml for the Mustard aphid (Lipaphis erysimi Kaltenbach) and soybean sucking bug (Chauliops choprai Sweet and Schaeffer), respectively. In the lepidopteran larvae treated with a concentration of 3 × 105 spores per ml, the fungus induced developmental abnormalities such as aberrant larval to pupal moulting, defective pupae, and deformed adults. Pathogenicity studies on the two beneficial insects (Coccinella septempunctata (Linn.) and Apis mellifera L.) and 11 host plants revealed no disease signs, indicating that it is safe for use in pest management in hill agriculture. The chitinolytic activity of the fungus and its crude protein extracts was reported in studies conducted against target insect pests, with the highest chitinase enzyme production (117.7 U/ml) on the fourth day of inoculation. Furthermore, over a 96-h period, third instar Helicoverpa armigera (Hubn.) larvae fed on a protein fraction-amended artificial diet showed a significant decrease in nutritional physiology indices such as relative growth rate, relative consumption rate, efficiency of ingested food conversion, efficiency of digested food conversion, and approximate digestibility. Moreover, the polyhouse and open-field studies against two sucking pests; Myzus persicae (Sulz.) infesting capsicum in polyhouse and L. erysimi infesting Indian rapeseed in open-field conditions showed, 81.14% and 63.14% mortality rates, respectively, at 3 × 107 spore/ml concentration.ConclusionsEntomopathogenic fungus (EPF) was reported to be an effective biocontrol agent, which caused direct mortality in sucking pests to developmental abnormalities in lepidopteran insects. Despite positive findings in in vitro and in vivo bioassay investigations against various insect pests, the fungus still has to be inspected before it can be used on a broad scale for biological pest management.

【 授权许可】

CC BY   
© The Author(s) 2022

【 图 表 】

12982_2022_119_Article_IEq51.gif

12982_2022_119_Article_IEq201.gif

12982_2022_119_Article_IEq198.gif

Fig. 1

12888_2022_4392_Article_IEq2.gif

12982_2022_119_Article_IEq184.gif

12982_2022_119_Article_IEq29.gif