Cotton leafworm

Cotton pests that are common both to the United States and tropical America include the cotton aphid (Aphis gossypii Glov.), the cotton leafworm [Alabama argillacea (Hbn.)], and certain grasshoppers and spider mites. Certain species of stink bugs, mirids, and cutworms which are closely related to species that occur here at times cause serious injury to cotton throughout Mexico and Central and South America. 

Vercruysse L, Smagghe G, Matsui T, Camp JV. (2008) Purification and identification of an angiotensin I-converting enzyme (ACE) inhibitory peptide from the gastrointestinal hydrolysate of the cotton leafworm, Spodoptera Littoralis. Process Biochem 43 900-904. 

With the introduction of the carbamate insecticides in 1956, resistance to carbaryl appeared between 1963 and 1966 in an orchard leafroller in New Zealand, in the cotton leafworm (Spodoptera) of Egypt, and in Heliothis virescens (the so-called tobacco bud-worm) on American cotton (Table VI). Resistance developed to OP compounds had already given some cross-tolerance to carbamates... 

The effect of these resistances has been to drive chemical control from one insecticide to the next. In most parts of the Nile delta the cotton leafworms can still be controlled by some OP compound, such as chlorpyrifos, supplemented where necessary with the insect growth regulator Dimilin. But in southern Texas, Mexico, Nicaragua and Peru the multiple resistances of the tobacco budworm, and to a less extreme degree of H. zea and Spodoptera sunia, have made even 20 insecticide applications a season quite worthless, and indeed there is less damage to the cotton if no chemicals are applied at all. The only materials that can be relied upon to kill these multiresistant H. viresoens are the dichlorovinyl pyrethroid NRDC-143 and the Heliothis nuclear polyhedrosis virus. 

Cotton leafworm [Lepidoptera Noctuidae] Spodoptera littoralis Boisduval... 

Small-scale field trials with fully stabilised micro-encapsulated formulations were carried out in Egypt during 1980 on two cotton pests - pink bollworm, Peotinophora gossypiella, and the Egyptian cotton leafworm, Spodoptera littoralis. Plots of 10 n x 10m were sprayed with the formulation and there were three replicates of each treatment. A plastic funnel trap (3) baited with synthetic pheromone was positioned at the centre of each plot. The effectiveness and persistence of communication disruption were measured by the reduction in catches of male moths in the traps in the treated plots relative to the catches in similar traps in untreated, control plots. 

Three stereoisomers of L-ascorbic acid were also bioassayed using the tobacco hornworm (Table I). Configurational changes at C4 and C5 aflFected activity and indicated that the geometry of C5 was more critical for activity than that of C4. The enantiomer, D-ascorbic acid, had approximately 40% activity, while the C5 epimer, D-isoascorbic acid, had 10% activity. The relative potency of those isomers is reversed in vertebrate and invertebrate animals. With D-isoascorbic, 2-10% activity in other insects was reported (20-22), but this compound did not promote development of the cotton leafworm (23). L-Isoascorbic acid had no activity in the hornworm or guinea pig. 

Spodoptera littoralis (Boisduval) Egyptian cotton leafworm larva FI, GR TD6TT07- 98-109... 

During an infestation by larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd) in the summer of 1978, it was noticed that shrubs of Physalis peruviana L. (cape gooseberry) were not attacked, whereas other Physalis and Nicandra spp. suffered heavy damage. Asher and co-workers demonstrated that withanolide E (118) and 4(3-hydroxywithanolide E (119), isolated from P. peruviana, as well as several related steroids, had insect antifeedant properties. Further studies on other withanolides showed antifeedant effects and species-specific activity on three insects, S. littoralis (Boisd.) (Lepidoptera), the Mexican bean beetle, Epilachna varivestis Muls. (Coleoptera) and the red flour beetle, Tribolium castaneum (Herbst) [62]. 

Stereoselective Wittig reaction. A stereoselective synthesis has been reported of the sex pheromone of the Egyptian cotton leafworm, (Z)-9,(E)-11-tetradecadien-l-yl acetate (3), by the Wittig reaction of (E)-2-pentenal (1) with (2) in dry dimethyl sulfoxide with dimsylsodium as base followed by deprotection and acetylation. The 9Z,11E- and 9E, 11 E-isomers were obtained in a... 

Orthosphenin (49), Fig. (16), the first example of an evoninol nucleus with an 0x0 group at C-8 and residual cassinic acid, was isolated from the hexane extract of the roots of Orthosphenia mexicana Standley and was found to have a lethal dosis (LD oo) of 0.01 p.g/cm2 against the fith-instar larvae of the Egyptian cotton leafworm Spodoptera littoralis [143]. 

Diflubenzuron can be either hydrolyzed at the urea bridge or oxidized by ring hydrox-ylation followed by conjugation. Hydrolytic cleavage seems to be a major route for diflubenzuron metabolism in many insect species. Two-spotted spider mites showed <10% absorption in 96 h of topically applied diflubenzuron. Of the amount absorbed, about 27% was metabolized in 96 h to 4-chlorophenyl urea, 2,6-difluorobenzoic acid, 4-chloroformanilide, 2,6-difluorobenzamide, and other metabolites. Effects of diflubenzuron were synergized by profenofos in cotton leafworm fourth instar larvae, and they were antagonized by 20-hydroxyecdysone in beetle (Tenebrio molitor) pupae. More information is needed on interaction effects of diflubenzuron with other chemicals. 

The last pesticide from this section is Flufenerim (Flumfen 302), which is under development by Ube Industries as an insecticide. It is reported to control aphids, whiteflies, and cotton leafworm, but has no activity against thrips [296]. Since Flufenerim is chemically related to Pyrimidifen (Miteclean 369) (Fig. 16), it was initially believed to have similar mechanism of action, i.e. inhibition of the mitochondrial electron transport of NADH dehydrogenase (NADH ubiquinone oxidoreductase, complex I) - an enzyme which transfers electrons from NADH to ubiquinone and hence opens the electron transport chain cascade. Nevertheless, it was shown that 302 reduced activity of acetylcholinesterase - an effect which possibly can be addressed to interaction with other systems [297]. 

With the exception of the corn earworm, fall armyworm, pink bollworm, and Egyptian cotton leafworm programs, these disruption tests were preliminary studies carried out on small plots without optimization of disruptant formulations and with little assessment of crop damage. 

Hall, D. R., P. S. Beevor, R. Lester, R. G. Poppi, and B. F. Nesbitt Synthesis of the major sex pheromone of the Egyptian cotton leafworm Spodoptera littoralis (Boisd.). Chem. Ind. London 1975,216—217. 

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