NEW RECORD OF ENTOMOPATHOGENIC BACTERIA, Bacillus aryabhattai STRAIN B8W 22, ISOLATED FROM Cassida vittata Vill. AND ITS PATHOGENICITY AGAINST THIS INSECT IN EGYPTIAN SUGAR BEET FIELDS

Abstract

Cassida vittata Vill. (Coleoptera : Chrysomelidae) is a very important insect pest to sugar beet crop. Its larvae and adults feed upon sugar beet leaves causing significant defoliation, consequently reduce root weight and sugar percent (%) to this crop. Entomopathogenic microorganisms, mainly entomopathogenic bacteria, is a vital factor of the natural mortality against insects. Research on microbial pathogens of insects is increasing to find out environmental friendly alternatives to hazardous chemical insecticides. This investigation was done at the Experimental Farm of Sakha, Agricultural Research Station, Kafr Elsheikh Governorate, Egypt during 2018 and 2019 seasons. Obtained results showed that 11(29.72%) C. vittata larvae out of 37 individuals died naturally with Bacillus aryabhattai. Six (29.72%) C. vittata adults out of 25 individuals died naturally due to exposure to 10 8 cfu/ml suspension, which used for laboratory and field tests. In a laboratory test, the mortalities of larvae were 20.00, 30.00 and 45.00% after 3, 7 and 10 days post-treatment, respectively. Whereas, the mortalities of adults were 10.00, 25.00 and 40.00% after 3, 7 and 10 days post-treatment, respectively. Also, in a field test, the reduction of larvae were 12.86, 29.79 and 43.99% for 3, 7 and 10 days after treatment, respectively. Reduction of adults were 14.06, 27.05 and 39.84% for 3, 7 and 10 days after treatment, respectively. This strain was identified by GATC (biotech sequence company, Germany), for the first time in Egypt. These results conclude that this strain is an effective biocontrol agent against C. vittata larvae and adults in sugar beet fields.

The First Field Evaluation of Bacillus thuriengiensis Bt407 against Cassida vittata and Its Natural Enemies In Egyptian Sugar Beet Fields.

“…(Coleoptera: Chrysomelidae) is one of the most devastating insects in sugar beet fields, especially the second (mid-September) and third (mid-October) (El-Dessouki, 2019). The larvae and adults of this insect feed upon sugar beet leaves causing reduction in sugar content and sugar root yield by 40.10 and 56.20%, respectively (Bazazo and Besheit, 2019). Many authors showed the importance of this insect pest on sugar beet crops since 1982 -until now e.g., Bassyouny and Beleih (1996) reported that the initial rate of infestation of C. vittata appeared on sugar beet plants late in December or on mid -January for all plantation.…”

“…Sheppard et al (2013) clarified that Bacillus thuriengiensis produces crystalline proteins during its stationary phase of growth which are lethal to Lepidoptera, Coleoptera and Diptera insects. Moreover, Bazazo et al (2015) and ( 2016) isolated a new strain of B. thuriengiensis from Pegomyia mixta Vill. and Scrobipalpa ocellatella Boyd larvae, as a first record in Egyptian sugar beet fields.…”