Susceptibility of desert locust, schistocerca gregaria (orthoptera: acrididae)‎ to bacillus cereus isolated from Egypt

الملخص EN

Examination was done at preliminary bracketing bioassay on one old 4th nymphal instar of desert locust.

Results showed that two isolates, namely NDL1 and NDL2 were having highly potentiality as entomopathogenic bioagents.

Thirty isolates were isolated from dead/ infected nymphs of desert locust occurred in raring cages at Department of Locust and Grasshoppers Research, Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt.

Molecular identification of isolated bacteria was done using universal primers of 16s rRNA, followed by DNA sequencing.

Nucleotides were blasted at (https://www.ncbi.

nlm.nih.gov /genbank/) to recognize that NDL1 and NDL2 isolates were two different isolates of Bacillus cereus with a high similarity (100%).

Susceptibility of 4th nymphal instar of Schistocerca gregaria (Forskal) to the isolated B.

cereus was determined using two bioassay procedures, Leaf-dip and per os.

The insecticidal activity of both isolates against locust nymph in leaf dipping showed that NDL2 was more efficient than NDL1.

However, the opposite trend was observed in using per os.

Both Isolates have the potential to be a successful biocidal agent to control desert locust.

INTRODUCTION Locust has been considered as one of the most destructive pest for economic crops/plants, all over the world due to the nature of damage that caused by locust swarm (Lecoq, 2001).

Conventional control of locust is mainly relied on chemical insecticides which are effective in suppressing the locust swarm (FAO, 2009).Several research programs have brought up to develop biocontrol agents against locust as a part of an integrated locust management (Prior & Greathead 1989 and Lomer et al 2001).

The major bacteria isolates tested as biocontrol agents are belonging to spore forming bacteria such as Bacillus thuringiensis, B.

sphaericus, B.

cereus and Paenibacillus popilliae, the entomopathogenic bacterium Yersinia sp.

(MH96), isolated from grass grub larva (Costelytra zealandica) (white) from New Zealand soils, showed high virulence against Locusta migratoria (Linnaeus, 1758), (Orthoptera: Acrididae) (Hurst and Glare, 2006).

This bacterium is causing death through secretion of toxin followed by rapid invasion of the host hemocoel overwhelming the insect within 72 h of infection (Hurst et al 2007).

Bacterial insecticides have been primarily developed for control of lepidopteran and dipteran pest.

A few products have been developed for control of beetle larvae (Sarwar, 2015).

The present study was aimed to isolation and identification of entomopathogenic bacteria from dead/infected nymphs of desert locust as well as the assessment of the entomocidal effects