Individual and synergist activities of monocrotophos with neem based pesticide, Vijayneem against Spodoptera litura Fab

• Published in: Physiological and molecular plant pathology 2018-01, Vol.101, p.54-68
• Main Authors: Radhika, S., Sahayaraj, K., Senthil-Nathan, S., Hunter, W.B.
• Format: Article
• Language: English
• Subjects: Azadirachta indica oil; Botanical insecticide; Lepidopteran; Monocrotophos; Synergism
• ISSN: 0885-5765; 1096-1178
• DOI: 10.1016/j.pmpp.2017.05.004

Evaluation of monocrotophos and Azadirachta indica oil, herein referred to as ‘Vijayneem’, were combined in ratios of 10% (10: 90), 20% (20: 80), 30% (30: 70), 40% (40: 60) and 50% (50: 50) [Monocrotophos: Vijayneem] under laboratory conditions to determine efficacy for properties of pesticidal, repellency, attraction, stimulant of consumption, development and reproduction. Asa biopesticide, Vijayneem oil (LC50 = 10.619%), caused greater mortality in dermal toxicity bioassays (LC50 = 18.045%) over ingestion. The greatest repellent activity was observed in third (Access Proportion Index = −0.25), fourth (API = −0.52) and fifth instar larvae (API = −0.67) in sprays of cotton leaves with monocrotophos. The detoxification enzymes like esterase (0.3, 11.1 μl/min/mg) and lactate dehydrogenase (6.8, 13.8 μl/min/mg) levels increased postingestion of treatments. Insects which ingested treated leaves showed an increase in carbohydrate (27.0, 18.0%), protein (4.7, 7.7%) and lipid (4.0, 10.4%) content. The greatest deformation of larvae, pupae and adults occurred in monocrotophos alone treatments, while the least deformities were recorded for monocrotophos + Vijayneem treatments. The male and female ratio and percentage of adult emergence was high in control than in A. indica oil alone treated S. litura. The greatest fecundity was observed in control (1620/4 female). In conclusion, the synergistic effects of A. indica oil + monocrotophos can be used for use the management of S. litura. [Display omitted] •Combinations of monocrotophos with neem oil at oral toxicity was more effective against Spodoptera litura larvae due to their antagonistic actions.•Comically monocrotophos suitably combined with neem oil which evidenced by FTIR and TEM analyses.•Both deterrent and attractant activities was observed due to monocrotophos or neem oil or their combinations.•Feeding with monocrotophos with neem oil treatment, modulate both digestive and detoxication enzymes.•Alternation of digestive physiology leads to larval, pupal and adult morphogenetic disorders.