Studying Of The Effect Of Fungi Beauveria Bassiana On The Biology And The Histology Of The Digestive Tract Of Schistocerca Gregaria

• Bissaad Fatima Zohra, ⁽¹⁾and Bahia Doumandji-Mitiche ⁽²⁾
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  ⁽¹⁾ National Protection Plants, P.O. Box 80, El-Harrach, Algeria E-mail: inpv@wissal.dz
  ⁽²⁾ National Agricultural Institute, El-Harrach, Algeria. E-mail: doumandjimitiche@yahoo.fr

Abstract

The desert locust S. gregaria in considered as a permanent threat to all kinds of plant products due to the damage it causes, specially during invasion periods. The only strategy to control this plague is to use chemical pesticides, which is not environmentaly safe. To find a safer way to control desert locust, a local clone of entomopathogenic fungus B. bassiana, isolated from Adrar (1600 km south Algiers) was tested. This fungus was applied to young 4 days old locusts (imagos). Different doses of this pathogen were applied D0: control, D1, D2, D3. The mortality of the insects varied from the 6th and the 9th day following the treatment. The LC50 obtained was 6.9x106 spores/ml. Histological sections in the digestive tract of the insects (control and treated) at LC50 were made according to the technique of MARTOJA & MARTOJA (1967). The different parts of the digestive tract showed significant differences between treated and non treated insects. Microscopic lesions in the intestine stomodeum and proctodeum (anterior and posterior) were caused by the pathogen with an alteration and dissociation occurred between intestinal epithelium and muscle. This means that insects died following food toxicity. The medium intestine (mesenteron) was resistant because of an important enzymatic activity present at this part of the digestive tract which showed down the pathogen action..