Oviposition Behaviour of the Cotton Leaf‐Worm Spodoptera littoralis (Boisd.) in Clover Field (Lepidoptera: Agrotidae)

Abstract

By early autumn, S. littoralis laid eggs on any erected object standing in or around the field, particularly the trunks of horsetail (Casuarina equisetifolia), camphor (Eucalyptus sp.), sesso (Dalbergia sesso) and babul (Acacia arabica) trees at a distance between 20 and 200 cm above the soil surface. Oviposition on weeds and wet soil surface around the seedlings was of frequent occurrence. In November, egg‐masses were deposited on the lower surface of clover leaflets, on the new growths arising from the bottom of the cut plants, or directly on the soil surface. Throughout winter, egg‐masses were hardly recorded in clover fields, but between early April and late June, they were commonly found on both surfaces of the leaflets as well as on numerous weeds. Egg‐masses laid on the soil surface were mostly of the large size, while those deposited at the other oviposition sites were smaller. After irrigation, egg‐masses population jumped to about 15 folds that occurring before irrigation. Spraying of weeds and tree trunks surrounding a clover field, and a narrow belt at its northern and western borders, were suggested to be practiced in the early autumn for the control of the cotton leaf‐worm in clover fields. Zusammenfassung Zum Eiablage‐Verhalten der Baumwolleule Spodoptera littoralis (Boisd.) in Kleefeldern Im zeitigen Herbst legte S. littoralis ihre Eier an alle aufrechten Objekte im Feld oder dessen Umgebung vornehmlich an die Stämme der Casuarina‐, Eukalyptus‐, Sesso‐ und Akazien‐Bäume in Entfernungen zwischen 20 und 200 cm über der Bodenoberfläche ab. Eiablagen auf Unkräutern und auf dem feuchten Boden in der Nähe der Klee‐Sämlinge kamen häufig vor. Im November wurden die Eier an die Unterseite der Kleeblätter, die Ausschläge der geschnittenen Kleepflanzen oder auf den Erdboden abgelegt. Während des Winters konnten in den Kleefeldern nur wenige Eier gefunden werden, aber zwischen Anfang April und Ende Juni waren sie wieder in Massen an beiden Seiten der Kleeblätter sowie an zahlreichen Unkräutern sichtbar. Die auf der Erdoberfläche abgelegten Ei‐Gelege waren größer als jene an anderen Stellen. Auf bewässerten Böden wurden bis zu 15mal mehr Eier als auf unbewässerten abgelegt. Das Sprühen von Unkräutern und Baumstämmen in der Umgebung des Kleefeldes bzw. in einem nördlichen und westlichen Gürtel mit Insektiziden im Frühherbst wird als praktikable Methode zur Bekämpfung des Schädlings angesehen.

RELATIVE ABUNDANCE AND FLIGHT ACTIVITY OF THREE COTTON LEAF WORM MOTHS, Spodoptera littoralis BIOSD. , Spodoptera exigua HB. AND Spodoptera latebrosa LED. AND THEIR PREDATORS USING A LIGHT TRAP AT MANSOURA DISTRICT.

“…Peaks of S. littoralis moths according to the biweekly catch occurred in the fourth week of April; the first week of June; the first week of July; the end of July; the second week of September; the end of October and the third week of November, representing seven peaks of moths per year (Table 1 and Figure 1). As indicated by Hassanein (1956), the moths of S. littoralis were captured in all month of the year at Shebin El-Kom and the maximum abundance was during June and July, while Abul-Nasr et al (1973) stated that peak numbers of S. littoralis moths were generally taken in about mid-June, late July and early September. They stated that the second and third peaks were higher than the fourth one.…”

“…(El-Deeb et al, 1968). Several investigators used light traps for studying the seasonal abundance and flight activity of one or more species of the cotton leaf worms moths as Hassanein (1956); El-Minshawy (1963); ; Abul-Nasr et al (1973) Shanab et al (1978); Foda and Romeila (1999) ;Vajgand, et al (2005) and Li, et al (2006).…”