Successive extraction of the green alga, Scenedesmus acutus 276–3a with different solvents indicated that the petroleum ether extract was the most repellent to the hatched larvae of Spodoptera littoralis. The application of spray emulsified 1 % petroleum ether extract inhibited egg laying. At 0.25% concentration the moths laid only 52.4 of their egg masses on the treated oviposition sites in comparison to the untreated control. Concentration of 1% was protective against the immature stage by hindering the third instar larvae to feed on treated leaf discs. In addition, the water emulsion of petroleum ether extract was insecticidal. The percentage mortality was directly proportional to the concentration applied and to the duration of exposure.

Different concentrations of essential oil of lemon grass, Cymbopogen citratus, were tested for their ovipositional inhibition, antifeedant activity and insecticidal properties against the lesser cotton leafworm, Spodoptera exigua. The results obtained showed that 2% concentration of oil emulsion inhibited egg laying and 0.5% concentration more than reducted by 70% the number of eggs deposited on oviposition sites. 2% concentration acts as a protective concentration against the immature stage by hindering the third instar larvae to feed on treated leaf discs. In addition, the oil emulsion was insecticidal in that percentage mortality was directly proportional to the concentration applied and to the duration of exposure. Older egg masses were more affected by treatment than the newly laid eggs. 2% concentration inhibited hatchability when sprayed on egg masses before hatching. Lemon grass oil effectively controlled S. exigua as an ovicidal and larvicidal agent.

The use of biogeographical techniques for monitoring, mapping and predicting seasonal changes in the distribution of migrant noctuid moths in a country or region, can lead to timely and effective control of infestations of the larvae of international pest species like the African armyworm, Spodoptera exempta (Wlk.); the American bollworm, Heliothis armigera (Hub.); the Black cutworm, Agrotis ipsilon (Hufn); the cotton leafworm, Spodoptera littoralis (Boisd.) etc., and hence to the protection of crops and pasturelands. Methods of data collection include the establishment of national and regional networks of monitoring devices such as light and pheromone traps, and the introduction of regular or periodic standard procedures for recording, reporting and assessing infestations of larvae. Techniques for collecting and analysing the data include the use of: (a) dots, circles or similar marks on topographic or weather maps to plot the occurrence of moths and/or larvae at the latitudes and longitudes of outbreak sites, followed by the dates when infestations were confirmed; (b) numerical symbols (e.g. 1–12 for January to December) on the above maps in order to summarize periodic (e.g. monthly) shifts in the distribution of populations within or across neighbouring countries; (c) colour codes or other graphic symbols to plot maps of pest distribution and migration over the required time-scale, followed by the study of appropriate synoptic weather charts, particularly streamline wind charts showing surface and low-level wind convergence zones over the distribution areas. Successful application of these techniques have included studies of changes in the distribution and migration of: (a) A. ipsilon worldwide; (b) Desert locust in Africa and Asia; (c) S. exempta in Africa and S.W. Arabia etc. In the 1981/82 outbreak season, for example, dots (•) were used to map out and date south-to-north displacement of populations of S. exempta across eastern Africa from Tanzania to Ethiopia between November 1981 and June 1982; while in 1980/81, numbers (1–12 for January-December) were plotted to summarize outbreaks developing between Ethiopia and Tanzania. Successful monitoring and assessment of mass movement of moths between Tanzania, Kenya and Uganda early in the 1981/82 season, for example, enabled the Armyworm Forecast Service to issue accurate forecasts for the first cross-border migrations of moths between the three countries from the second week of February 1982, leading to effective control of larvae to save cereal crops, sugar-cane and pasture grasses in East Africa.

The effectiveness of Bacillus thuringiensis var. galleriae HD-129 against the moths and egg masses of the cotton leafworm, Spodoptera littoralis, has been demonstrated in laboratory experiments. The longevity and egg production were significantly affected when the moths were fed on a sucrose diet containing 17.2 × 103 IU of the tested formulation/mg or higher rates. At lower concentrations (4.4−8.7 × 103 IU/mg), the females gave normal egg production, but the longevity was adversely affected. Investigations show that a formulation with spores alone affects the egg production and hatching, while a formulation with active crystals alone had no effect on egg production. Sprays of B. thuringiensis combined with sucrose on flowering cotton plants seem to affect the biology of the moths released on it. Egg masses sprayed with B. thuringiensis hatched normally, but the survival of the hatched larvae was reduced when treatment was made shortly before egg hatching. Based on the results obtained, B. thuringiensis showed a promising effect in the control of the moth S. littoralis as well as an ovicide larvicide agent.