AUTHOR=Ramdani Chaimae , El Fakhouri Karim , Boulamtat Rachid , Bouharroud Rachid , Mesfioui Abdelhalim , Al-Jaboobi Muamar , El Bouhssini Mustapha 

TITLE=Entomopathogenic fungi as biological control agents of Dactylopius opuntiae (Hemiptera: Dactylopiidae) under laboratory and greenhouse conditions

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=Volume 6 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2022.997254

DOI=10.3389/fsufs.2022.997254

ISSN=2571-581X

ABSTRACT=The prickly-pear cactus Opuntia ficus-indica L. is grown throughout Morocco and has an important economic role as a source of food, animal feed and income for rural populations. However, this crop is attacked by a sap-sucking insect pest, the wild-scale Dactylopius opuntiae (Cockerell), which has caused huge production losses since its introduction to the country in 2014. The present study investigated the entomopathogenic effect of six fungal isolates (Beauveria bassiana (HASS; RFSL10; SPT 011(a)); Verticillium lecanii (RFSLV; SPT R 215) and Paecilomyces farinosus (SPSBI4)) for controlling D. opuntiae nymphs and adult females under laboratory bioassays and greenhouse conditions. Under laboratory conditions, the highest mortality rates of D. opuntiae females was registered by B. bassiana strain HASS at 108 conidia mL-1 with 100%, followed by B. bassiana strain RFSL10, V. lecanii RFSLV, and P. Farinosus SPSBI4 isolates with 98%, respectively, 10 days after treatments. Similarly, the highest level of nymph mortality (100%) was recorded by B. bassiana RFSL10 and HASS isolates at 108 conidia mL1, respectively, 4 and 5 days after application. Under greenhouse conditions, B. bassiana (HASS and RFSL10) and V. lecanii (RFSLV) isolates sprayed alone expressed a higher toxicity on nymphs with 75, 68.5 and 58%, respectively, 12 days after treatments. However, no significant difference was observed in adult female’s mortality between different fungal isolates, where B. bassiana (HASS) at 108 conidia mL-1 presented a moderate mortality rate with 55%, 12 days after application. In fact, the combination of black soap (60 g/L) with B. bassiana HASS and RFSL10 and V. lecanii (RFSLV) isolates at 108 conidia mL-1 caused the highest toxic activity on D. opuntiae adult females, with 70.5, 68.75 and 67.65%, respectively. These findings showed that entomopathogenic fungi are promising for developing a biopesticide formulation for the control of D. opuntiae as a safe alternative to chemical insecticides.