Evaluation of the entomopathogenic fungi as a non-traditional control of the rice leaf roller, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) under controlled conditions

Abstract

The rice leaf roller or leaf folder, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae), is a serious pest of rice crop in Pakistan. The present study was carried out to evaluate the virulence of the entomopathogenic fungi (EPF) Beauveria bassiana, Verticillium lecanii, and Metarhizium anisopliae against the third instar of C. medinalis larvae. Larvae were exposed to fungi under controlled conditions at the available commercial concentration (1 × 10 8 conidia ml −1 ). The results showed 73.33, 57.78, and 74.44% mortality rates in the in vitro assay and 56.67, 41.11 and 52.78% in the greenhouse assay of B. bassiana, V. lecanii, and M. anisopliae, respectively. The maximum mycosis from cadavers of C. medinalis was observed at B. bassiana treatment in the in vitro assay (70%) and in the greenhouse assay (53.78%). The maximum sporulation from C. medinalis cadavers was observed at B. bassiana treatment in the in vitro assay (144.67 conidia ml −1 ) and in greenhouse assay (96.67 conidia ml −1 ). These results favor the alternative use of EPF in organic rice production for management of C. medinalis.

Effect of the entomopathogenic fungus, Beauveria bassiana, combined with diatomaceous earth on the red flour beetle, Tribolium castaneum (Herbst) (Tenebrionidae: Coleoptera)

“…Batta (2004) found that the conidial viability of fungus decreased with time, but its insecticidal efficacy was not badly affected. This trend has also been reported in case of some greenhouse and field trials and pests such as the rice leaf roller, C. medinalis (Rizwan et al 2019), and the whitefly Bemisia tabaci (Gennadius) (Batta 2003), respectively. Fungal pathogens are more advantageous in bio-control cases as these could recycle in cadavers producing conidiospores that are reintroduced into the eco-system (Thomas et al 1997 andStathers 2002).…”

“…The strain of B. bassiana isolate used in this study was obtained from dead cadavers of rice leaf folder, Cnaphalocrocis medinalis (Guenée) (Rizwan et al 2019). The fungus was then sub-cultured on Potato Dextrose Agar (PDA) plates for bulk generation of the fungal conidia.…”

Nondetrimental impact of two concomitant entomopathogenic fungi on life history parameters of a generalist predator, Coccinella septempunctata (Coleoptera: Coccinellidae)

“…Considerable advancements are reported in the field of insect pathology and the role of entomopathogenic microorganisms is widely investigated for effective pest control under controlled and open field conditions 14 . Currently, biopesticides are being used for insect pest management due to less hazardous impact on the environment, beneficial fauna, and ultimately human health 21 , 22 . Entomopathogenic fungi (EPFs) have been used for the management of insect pests ranging from stored grain pest management 23 , laboratory testing 22 , greenhouse assay 21 , and field trials 24 .…”

“…Currently, biopesticides are being used for insect pest management due to less hazardous impact on the environment, beneficial fauna, and ultimately human health 21 , 22 . Entomopathogenic fungi (EPFs) have been used for the management of insect pests ranging from stored grain pest management 23 , laboratory testing 22 , greenhouse assay 21 , and field trials 24 . However, studies regarding the impact of these biopesticides including EPFs on the biological control agents naturally present in the field are still a researchable topic.…”

“…EPFs have been reported as an effective tool in controlling a broad range of insect pests 21 , 22 , 25 , 26 . High virulence makes the EPFs a useful strategy against insect pests.…”