Effect of bio-rational insecticides on some biological aspects of the Egyptian cotton leafworm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Abstract

The bio-rational insecticides Dipel 2x, BioFly, Agrin, BioGuard, Spinosad, Neemix, Mectin and Match were tested for their effect on 1<sup>st</sup>, 3<sup>rd</sup> and 5<sup>th</sup> instar larvae and egg masses (24, 48 and 72 h old) of the Egyptian cotton leafworm <i>Spodoptera littoralis</i> under laboratory conditions. The doses used were the recommended dose, half of the recommended dose and quarter of the recommended dose. All insecticides caused higher mortality in the 1st than in the 3<sup>rd</sup> and 5<sup>th<sup> larval stage, although Match, Mectin and Spinosad at all tested concentrations showed excellent efficacy against the 3<sup>rd</sup> larval stage of <i>S. littoralis</i>. Also, Match resulted in 100% mortality of 5<sup>th</sup> instar larvae at all tested concentrations. Moreover, these insecticides also strongly affected some biological parameters of treated 3<sup>rd</sup> and 5<sup>th</sup> instar larvae of <i>S. littoralis</i>. Egg masses of different ages (24, 48 and 72 h old) where dipped into the recommended dose of each insecticide and the mortality rates determined; eggs of different ages were affected similarly, with mortality rates of 83.4, 85.0 and 71.7%, respectively, after treatment with Spinosad compared to the control. In general, eggs 48 and 72 h old were less sensitive than 24 h old ones. A latent effect of the insecticides on egg hatchability of <i>S. littoralis</i> was observed only in Match and Neemix, with the average being 55.0% and 51.6%, respectively. Our results suggest that Match, Mectin and Spinosad are potentially potent compounds for control of <i>S. littoralis</i>.

Evaluation the Efficacy of Certain Bio-Rational Insecticides on Tuta Absoluta (Lepidoptera, Gelechiidae) on Tomatoes under Laboratory and Field Conditions

“…Lufenuron (Match ® ) showed very low toxicity against the first instar larvae of TLM, but no toxicity was observed against fourth instar larvae with subsequent lower reduction in TLM infestation under field conditions. These results are in disagreement with those reported by Osman and Mahmoud (2008) who demonstrated that Match ® gave 100% mortality of 5 th instar larvae of S. littoralis.…”

Efficacy of Some Biopesticides and Their Field Persistence on Cotton Plants Against Spodoptera littoralis (Boisd.)

“…Also the field experiment showed high mortality 91.4% after 2 days then reduced gradually to reach 83.1% after 8 days. Osman and Mahmoud (2008). Semi field studies: Data in Tables (2&3) showed the efficiency of recommended concentrations of Spinetoram and Dipel 2X against 2 nd and 4 th larval instars of S. littoralis under semi field condition.…”

The activity of Bacillus thuringiensis Vectobac G on the biochemical compositions of Culex pipiens and Culiseta longiareolata (Diptera: Culicidae) mosquito larvae

“…In this opinion, Tanani et al, (2021) reported that the reduction of protein content in larvae and pupae of Galleria mellonella after larval treatment with the tested arthropod venoms, can be interpreted in the light of some conceivable suggestions: "(1) the proteins might be due to their binding with the tested arthropod venoms and therefore might reflect the depressed activity of the detoxifying enzymes. (2) that the protein plays a major role in synthesis of the microsomal detoxifying enzymes against toxicants (foreign compounds) entering into the insect body (Hassan, 2002). (3).…”