- Wednesday, January 1, 2003
- Symptomatology of Tobacco Whitefly and Red Spidermite Infection with the Entomopathogenic Fungus Metarhizium Anisopliae (Metsch.) Sorokin
- Published at:Agricultural Sciences , Dirasat Journal, Volume: 30, Issue: 3, 2003, 294 - 303
The present research aimed at describing the macroscopic and microscopic symptoms of infection with the entomopathogenic fungus Metarhizium anisopliae on tobacco whitefly (Bemisia tabaci) and red spidermite (Tetranychus cinnabarinus). For this, conidial suspensions of the fungal strain Meta 1 were applied against larvae and pupae of B. tabaci, and adults and nymphs of T. cinnabarinus infesting eggplants under laboratory and simulated field conditions. Results obtained have indicated that infected larvae and pupae of B. tabaci turned into black-greenish color due to the fungus-attack 3 days after treatment and incubation at 20?1oC and 100% RH using two types of incubation techniques. Infected nymphs and adults of T. cinnabarinus also turned into dark-brown color 3-4 days after treatment and incubation under similar conditions to B. tabaci. The same color change in both pests due to the fungus-infection under simulated field conditions (19-30oC and >90% RH) was also obtained. Dark-brown fungal outgrowth and sporulation was observed on the cadavers of treated individuals with the fungus in both pests 5 days after treatment and incubation under the above-mentioned conditions. Microscopic examination of infected individuals of B. tabaci or T. cinnabarinus have indicated that typical mycelia and conidia of M. anisopliae were observed on their surface. Moreover, dense mycelial growth of the fungus was also observed under higher microscopic magnifications in the hemocoel of attacked individuals of B. tabaci or T. cinnabarinus. The latter observation was realized after a careful superficial sterilizaton of the infected individuals of both pests, then mounting and clearing them in lactophenol before examination. Overall results refer to the possibility of using the fungus in biocontrol of both pests.