Ziad Al-Eisa ^(1)*, Mohammad Nayef Alsalty ⁽²⁾, Ahmad Algomaa⁽¹⁾ and Moneer Alnabhan⁽³⁾

• Cotton Administration Research, Aleppo, Syria.
• Plant Protection Department, Faculty of Agriculture Aleppo University, Aleppo, Syria.
• Agricultural Research Centre in Hama, General Commission for Scientific Agricultural Research, Hama, Syria.

(*Corresponding author: Eng. Zaid Al-Esia Email: ziadissa989@gmail.com)

Received: 8/07/2020          Accepted: 13/09/2020

Abstract:

Cotton aphids consider important due excreting honeydew and its negative side effects on cotton lint which reduce its quality and economic value, and in cases of outbreaks can improve  resistance to chemical pesticides which is used in control, Biocontrol considers alternative method to chemical pesticides and useful method in controlling insects and acari, survey of entomopathogenic fungi to cotton aphids A. gossypii was conduct in AL-Gab countryside/Hama district in the season 2018 by collecting infected leaves, surface sterilization to dyed insects was conduct by (Lacey and Brooks,1997) methods, those insect moved to Petri dishes contains PDA(Potato dextrose agar) medium, then those dishes were incubated on 22±2 °C until the surficial fungal growth on sterilized insects appeared , then an abrasive from the surficial fungal growth were taken to new petri dishes contain SDYA_1/4 medium, the fungal strains were purified and identified by using manual which described by )Humber, 1997(, The effectivity of the isolated strain from cotton aphids A. gossypii was confirmed in initial experiment; The effects on life cycle of cotton aphids A. gossypii   of the strain ASP from Aspergillus sp. Fungi and GHA strain from B.bassiana fungi was achieved with four different concentrations 5×10⁵, 5×10⁶, 5×10⁷ , 5×10⁸ conidia /ml of each strain throw spraying the nymphs which were collected from infected fields by the fungal spore suspension whereas control treatment sprayed by distilled water in the same way. The results showed that the strain is from Aspergillus genus, and from the initial experiment was found that the dyed insect which appeared on them the fungal growth of the tow strains ASP and GHA after surface sterilization reached 95% and 74.41% respectively, which confirm that is the isolated strain is entomopathogenic fungi on cotton aphids. The value of lethal dose 50(LD₅₀) for the ASP, GHA strains was 1.297׳10,10⁸x 3.963 conidia /ml respectively, and the lethal time50(LT₅₀) was for ASP, GHA strains 3 and 8.693 days respectively, which lead to that is ASP strain promise strain in IPM programs of cotton aphids.

Keywords: Aspergillus, cotton aphids, Entomopathogeneic fungi, LC50, LT50.

Full paper in Arabic: PDF