SUSCEPTIBILITY OF DIFFERENT STAGES OF A FIELD STRAIN OF THE COTTON LEAF WORM Spodoptera littoralis (BOISD.) TO TWO BIOINSECTICIDES AND TWO INSECT GROWTH REGULATOR COMPOUNDS UNDER LABORATORY CONDITIONS
HEBA M. S. EL- BANNA
Department of Cotton Leafworm Research, Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, P.O.Box 12611, Egypt.
MARWA M. M. A. EL- SABAGH
Department of Cotton Leafworm Research, Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, P.O.Box 12611, Egypt.
SARA M. I. ABD EL-KAREEM *
Department of Cotton Leafworm Research, Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, P.O.Box 12611, Egypt.
SUZAN A. IBRAHIM
Department of Cotton Leafworm Research, Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, P.O.Box 12611, Egypt.
*Author to whom correspondence should be addressed.
Abstract
The current study was conducted in order to evaluate the most susceptible stage of the field strain of the cotton leafworm, Spodoptera littoralis to four commercial compounds: two commercial biopesticides and two IGRs compounds, under laboratory conditions. The 1st, 3rd and 6th instar larvae were treated with quarterly recommended concentration of each tested compound separately. Results revealed that the treatment with tested compounds caused high cumulative mortality against young instar larvae, i.e. 1st and 3rd instar larvae, while no significant high larval mortality observed for 6th instar larvae. In addition, several latent impacts were observed as a reduction in larval and pupal duration, minimized adult emergence, reduced adult longevity, fertility, and fecundity and formation of intermediates and malformed pupae and adults. The study concluded that examined compounds can have a priority as a safe and reliable alternative for conventional insecticides.
Keywords: Spodoptera littoralis, entomopathogenic fungi, IGRs, biological aspects, reproductive capacity