Toxic Impact of Some Insect Growth Regulators and Biocides in Relative to Chlorpyrifos to Cotton Leafworm, Spodoptera Littoralis (Boisd.)

Abstract

The stomach poisonous impact of some insect growth regulators and biocides was tested under laboratory and semi-field conditions against cotton leafworm, S. littoralis. Obtained results revealed that, the second instar larvae reflected higher level of susceptibility towards all the tested insecticides than fourth one. According to LC 50 and LC 90 values, chlorpyrifos was the most effective insecticide that recorded 0.1 and 0.809 ppm for 2 nd instar larvae and 0.472 and 6.838 ppm for 4 th instar larvae, respectively. Meanwhile, tebufenozide appeared to be the least effective compound against both tested instars that gave 9.901and 36.447 ppm against 2 nd instar, whereas the LC 50 and LC 90 values were 65.736 and 1000.775 ppm) against the 4 th one, respectively. The rest compounds gave moderate effects in this respect.Data concerning the initial and residual activity of the tested insecticides, Tracer, XDE, methoxyfenozide, Dipel 2x and chlorpyrifos against 4 th instar larvae of field strain cotton leafworm, S. littoralis were determined. The initial effect calculated as the cumulative mortalities at zero time recorded 100, 100, 92, 88 and 26 % for methoxyfenozide, chlorpyrifos, XDE, Tracer and Dipel 2x, respectively. The untreated check recorded 2%, methoxyfenozide and chlorpyrifos gave the highest significant mortalities effects comparing to the untreated, Chlorpyrifos and methoxyfenozide were detected the highest significant mortalities effect as general residual effect whereas Dipel 2x recorded the least significant mortality effect, which it being 18.40% as compared to other insecticides.

Comparative Effect of Some Bio Insecticides with Chlorpyrifos on Cotton Leafworm

“…The increased mortality percentages by increasing the concentrations of Dipel 2x agree with those previously reported by: Kareset al, (1992) on larvae of the cabbage worm Artogeiarapae when testing Bactospeine; when he tested Dipel 2x, Ecotech bio and MVP11 against S. littoralis and the potato tuber moth Phthorimaea operculella; where also Ecotech bio and MVP11 were more effective than Dipel 2x against the second and fourth larval instars of S. littoralis, El-Khawas (2000) on the olive leaf moth, Palpita unionalis larvae by using the bioinsecticide. Also, El-khayat et al (2012), reported that the second instar larvae reflected a higher level of susceptibility towards all the tested insecticides that included: Insect growth regulators (Nomolt 15% Mimic 24% and Runner 24%); Tracer,XDE and Dipel 2x;and Organophosphorus (Chlorpyrifos) than the fourth one. They found that LC50 and LC90 values, chlorpyrifos was the most effective insecticide recorded 0.1 and 0.809 ppm for 2nd instar larvae and0.472 and 6.838 ppm for 4th instar larvae, respectively, while, tebufenozide appeared to be the least effective compound against both tested instars that gave 9.901and 36.447 ppm against 2nd instar, and 65.736 and 1000.775 ppm against the 4th one, respectively.…”

“…Results in Tables 3 & 4 indicate larval duration, % mortality of larvae, pupation percentage, pupation period & % of moth emergency in both 2 larval stages 2 nd and 4 th instar larvae. Results indicated that DipleDf is the most increased in larval and pupation duration followed by Jojoba, while Chlorypyrifos is the last one compared by the control Also, El-khayat et al (2012), reported that the second instar larvae reflected a higher level of susceptibility towards all the tested insecticides that included: Insect growth regulators (Nomolt 15% Mimic 24% a Runner 24%); Bio-insecticides, Tracer, XDE, and Dipel 2x; and Organophosphorus (Chlorpyrifos) than the fourth one. They found that LC50 and LC90 values, chlorpyrifos was the most effective insecticide recorded evidently favored by the cotton leafworm and severe damage is annually caused to most crop growers.…”

Potential Insecticidal Effect of a Wasp (<i>Polistes dominulus</i>) and a Bee (<i>Apis mellifera</i>) Venoms in Controlling <i>Spodoptera littoralis</i>

“…Eight replicates were used for each treatment. Cumulative mortalities were calculated at the end of each testing time [26].…”