Laboratory evaluation of the effect of the entomopathogenic fungi, Hirsutella thompsonii and Paecilomyces fumosoroseus, against the citrus brown mite, Eutetranychus orientalis (Acari: Tetranychidae

Abstract

El-Sharabasy H.M. (2015): Laboratory evaluation of the effect of the entomopathogenic fungi, Hirsutella thompsonii and Paecilomyces fumosoroseus, against the citrus brown mite, Eutetranychus orientalis (Acari: Tetranychidae). Plant Protect. Sci., 51: 39-45.Formulations of the entomopathogenic fungi Hirsutella thompsonii (Fisher) and Paecilomyces fumosoroseus (Wize) Brown and Smith were tested against all stages of this pest under laboratory conditions. Three concentrations: 0.5 × 10 9 ,1.0 × 10 9 , and 2.0 × 10 9 conidia/ml were sprayed on leaf discs containing larvae, nymphs, and adults, while a single dosage of 1.0 × 10 9 conidia/ml was sprayed on eggs as ovicide. All the life stages were susceptible to both fungal pathogens at the tested concentrations. Larval and nymphal stages were generally less susceptible than adults. Based on probit analysis, H. thompsonii was the highest virulent with LC 50 and LT 50 (358, 290, and 146 conidia/ml and 7.78, 7.11, and 6.92 days) and P. fumosoroseus (597, 589, and 339 conidia/ml and 7.49, 7.14, and 4.31 days) for larvae, nymphs, and adults, respectively. However the efficacy of the two pathogens evaluated clearly differs from that of the controls. Compared with controls, egg hatchability was reduced at the different pathogen concentrations used. H. thompsonii at LC 50 was more effective against eggs. Also, females in the control laid more eggs than those treated with the fungi. The entomopathogenic fungi H. thompsonii and P. fumosoroseus could be considered as an environmentally friendly alternative for biocontrol of E. orientalis.

Paecilomyces and Its Importance in the Biological Control of Agricultural Pests and Diseases

“…Paecilomyces has been described to control pests by limiting insect growth as a result of reduced feeding [ 236 , 239 ] reproduction [ 240 ] or simply causing their death due to mycosis [ 241 ]. In addition, it has been shown that P. fumosoroseus is capable of causing more deaths than some commercial insecticides such as fipronil when used against Frankliniella occidentalis [ 242 ].…”

Effect of temperature degrees on the duration of the phytophagous mite, Eutetranychus orientalis complex (klein) (acari: Tetranychidae) when fed on green bean (Phaseolus vulgaris L.)

“…Among them, the citrus brown mite, Eutetranychus orientalis (Klein), is especially significant as the most polyphagous species in field and greenhouses in the Middle East, Africa, and Asia. It represents a serious pest of a wide variety of agricultural, ornamental and medicinal plants (Rasmy, 1978;Dhooria, 1985;Gupta, 1985;Kandeel et al, 1986;Sewify and Mabrouk 1991;Sangeetha and Ramani, 2011;El-Sharabasy, 2015).…”

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

“…Beauvaria bassiana and M. anisopliae are being considered and used throughout the world as strong and effective biological control agents 33 . However, the success of these fungal species as biocontrol agents does not depend only on the selective and effective killing of insect pests but also on very few or no adverse effects against beneficial non-target insects present in the field.…”