Endophytic actinobacteria from wild medicinal plants are a natural source of insecticide to control the African cotton leafworm (Spodoptera littoralis)

AMB Express

Table 2 Toxicity of the potent metabolic extracts to the fourth instar larvae of Spodoptera littoralis, laboratory and field strains, at concentration 100 mg/mL

Actinobacteria		Laboratory strain mortality		Field strain mortality
Code	genus	Immediate ^a	Latent ^b	Immediate	Latent
11	Nocardioides sp.	+ + +	+	+ +	+
19	Nocardioides sp.	+ + +	+ + +	+ +	+
26	Streptomyces sp.	+ + +	+ + +	na	+ +
53	Streptomyces sp. ES2	+ + +	+	+ + +	+
62	Streptomyces sp.	+ + +	+ + +	na	na
67	Pseudonocardia sp.	+ + +	+	na	na
68	Streptomyces sp.	+ + +	na	na	+ +
Dist. Water Control		–	–	–	–
EtAc Solvent Control		na	na	na	na
Radiant SC 12% Control		+ + +	na	+ + +	na

^a, death within 72 h; ^b, late death of larval/pupal stages;
+ + + , 50–30% mortality; + + , 29–11% mortality; + , ≤ 10% mortality of pupal stage; na, no activity
Dist. Water Control: are S. littoralis larvae fed on leaves sprayed with distilled water; EtAc Solvent Control: are S. littoralis larvae fed on leaves sprayed ethyl acetate solvent. All bioassay assessments were duplicated (each replicate included four larvae)