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Dactylopius opuntiae (D. opuntiae), commonly referred to as cochineal scale insect or wild cochineal, poses a considerable risk to cactus plantations globally. Various control methods, including chemical pesticides and biological treatments, have been employed to control the D. opuntiae pest. This paper presents an innovative approach to use microwave radiation as a pest management method for D. opuntiae, in cactus plantations. This method stands out due to its advantages of selective treatment, chemical free, and no environmental impact. This research work details the use of plane wave for simulating the influence of microwave radiation using electromagnetic model, on cactus pear and three distinct stages of adult females of the D. opuntiae. The findings demonstrated that the distribution of thermal energy indicates the ability of electromagnetic radiation to raise D. opuntiae’s thermal energy above that of the cactus pear at various industrial, scientific, and medical (ISM) band frequencies. Additionally, the developed microwave heating system demonstrates the capability of microwave radiation at 2.45 GHz to eliminate various stages of adult D. opuntiae without harming the host plant’s quality. The study also explores the impact of adjusting input power and treatment duration to manage D. opuntiae effectively.

Abstract The Opuntia ficus-indica (L.) cactus, a crucial crop in Morocco, is threatened by the wild cochineal, Dactylopius opuntiae (Cockerell). The aim of this research was to investigate the efficacy of nine bacterial strains against both D. opuntiae nymphs and adults females applied individually or after black soap in the laboratory, greenhouse, and field conditions. Using the partial 16S ribosomal DNA, the bacterial isolates were identified as Pseudomonas koreensis, Pseudomonas sp., Burkholderia sp. and Bacillus sp. Under laboratory conditions, the insecticidal activity of P. koreensis strain 66Ms.04 showed the level mortality (88%) of adult females’ at 108 CFU/mL, 7 days after application. At a concentration of 108 CFU/mL, P. koreensis strain 66Ms.04 and Pseudomonas sp. (strains 37 and 5) caused 100% nymphs mortality rate three days after application. Under greenhouse conditions, the use of P. koreensis strain 66Ms.04 at 108 CFU/mL following the application of black soap (60 g/L) demonstrated the maximum levels of females and nymphs’ mortalities with 80 and 91.25%, respectively, after 8 days of treatment. In field conditions, the combined application of the P. koreensis strain 66Ms.04 at 108 CFU/mL with black soap at 60 g/L, for an interval of 7 days, significantly increased the mortality of adult females to 93.33% at 7 days after the second application. These findings showed that the combined treatment of P. koreensis strain 66Ms.04 with black soap can be a potent and eco-friendly pesticide against D. opuntiae.

The cactus Opuntia ficus-indica L. is widly cultivated in Morocco and has a very an important economic role as a source of food, livestock feed and not forgetting that it is considered to be an income for people in rural communities. This crop is subject to the attack of a serious insect pest, the Dactylopius opuntiae (Cockerell), which sucks the sap from the plant causing 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)]; Akanthomyces lecanii [RFSLV; SPT R 215] and Cordyceps farinosa [SPSBI4]} for controlling of both nymphs and adult females of D. opuntiae in laboratory and greenhouse bioassays. Under laboratory conditions, the highest mortality of female D. opuntiae was registered by B. bassiana strain HASS at 108 conidia ml−1 with 100%, followed by B. bassiana strain RFSL10, A. lecanii RFSLV, and C. farinosa 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 A. 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 A. 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 management of D. opuntiae as an adequate and safe alternative to chemical pesticides.

The wild cochineal Dactylopius opuntiae (Hemiptera: Dactylopiidae) is one of the major insect pests of the prickly pear Opuntia ficus-indica (L.) in Morocco, a well-known fruit and vegetable crop of arid and semi-arid regions around the world. The present study investigated the insecticidal potential of six extracts (three aqueous and three hydroalcoholic (MeOH/H2O, 20/80 (v/v)) from Atriplex halimus (leaves), Salvia rosmarinus (leaves) and Cuminum cyminum (seeds) to control nymphs and adult females of D. opuntiae under laboratory and greenhouse conditions. Out of the tested samples, A. halimus aqueous extract showed the highest activity, inducing mortality rates of 67.04% (after 4 days) and 85% (after 8 days) on nymphs and adult females of D. opuntiae, respectively, at a concentration of 5% under laboratory conditions. It also showed the highest mortality rate of nymphs with 100% (4 days after application) and 83.75% of adult females (7 days after the second application) at a concentration of 5% when combined with black soap at 10 g/L under greenhouse conditions. The difference in the toxicity of plant species of the study was correlated with their saponin content. A total of 36 of these triterpene glucosides were suggested after a comprehensive LC-MSn profiling of the most active extract, A. halimus, in addition to phytoecdysones and glycosylated phenolic acids and flavonoids. These findings provided evidence that the aqueous leaf extract of A. halimus could be incorporated in the management of the wild cochineal as an alternative to chemical insecticides.

The carmine cochineal Dactylopius opuntiae (Cockerell) is the major insect pest of the prickly-pear cactus Opuntia ficus-indica (L.) in Morocco. The present study investigated the insecticidal activities of six essential oils (EOs) against nymphs and adult females of D. opuntiae applied singly or in combination with a detergent under laboratory and field conditions. Under laboratory conditions, M. pulegium and O. vulgare L. essential oils showed a high level of insecticidal activity at 5%, with 98% and 92% females’ mortality, respectively, 5 days after treatments. The M. pulegium and O. vulgaris oils at 5% applied in combination with black soap at (60 g/L) induced the highest toxic activity on adult females, 100% and 96% at 5 days after treatments, respectively. Under field conditions, M. pulegium and O. vulgare oils at 5% in combination with black soap (60 g/L) showed the highest adult female mortalities with 96.33 and 92.56%, respectively, 7 days after the first application. The double application of M. pulegium oil at 5% significantly increased the mortality of adult females up to 91%, 5 days after the second spray. GC-MS analysis revealed that the most abundant constituent of M. pulegium and O. vulgare oils was pulegone (84.69%) and durenol (76.53%), respectively. These findings showed that the use of M. pulegium and O. vulgare in combination with black soap or in double sprays could be incorporated in the management package for the control of the wild cochineal D. opuntiae, as a safe and natural alternative to chemical insecticides.