Interactions between different initial densities of the predator Allaeocrcmum biannulipes and its preys were investigated. Four initial densities (3, 6, 9 and 12 pairs/vial) and three preys, Corcyra cephalonica, Tribolium confusum and Anagasta kuehniella were checked at 15–26 °C and 45–60% r. H. Associating with the latter prey, the pest's population showed a negative response towards the increase of the initial density of the predator up to 9 pairs/vial. However, in association with the other two preys, a reverse trend took place. The appropriate initial density with which the predator could face its victim was checked against the prey A. kuehniella under two hygrotherimic conditions: 15–26 °C/45–60% r. H. and 22–23 °C/38–60% r. H. At the former conditions, the predator was most efficient as it was able, with the density of 6 pairs/vial, to build up its population and to suppress that of its prey. However, in summer months (22–23 °C/38–60% r. H.), conditions were in favour to the pest than to the predator and consequently, the highest density of the latter built with the intial density of 9 pairs/vial was associated with a relatively high density of the prey. Zusammenfassung Zur Wirkung der Raubwanze Allaeocranum biannulipes (Montr. et Sign.) auf die Populationen einiger vorratsschädlicher Insekten Es wurden die Beziehungen zwischen verschiedener Anfangsdichte der Raubwanze A. biannulipes und der Enddichte ihrer Beutetiere Corcyra cephalonica, Tribolium confusum und Anagasta kuehniella bei 15–26°C und 45–60% rel. LF untersucht. Letzterer Schädling reagierte auf eine Zunahme der Anfangsdichte der Raubwanze bis hinauf zu 9 Paar/Gefäß mit einer Verminderung der Dichte. Jedoch war bei den beiden anderen Schädlingsarten ein umgekehrter Trend zu beobachten. Die optimale Anfangsdichte der Raubwanze wurde bei 2 Temperatur‐Luftfeuchte‐Bedingungen (15–26°/45–60% und 22–23°/38–60%) ermittelt. Bei der erstgenannten Bedingung war der Prädator am wirksamsten: er baute seine Population von 6 Paar/Gefäß ausgehend auf und reduzierte die Dichte seiner Beute. Dagegen wirkten die Sommerbedingungen (22–23°/38–60% zugunsten des Schädlings: eine Anfangsdichte von 9 Paar/Gefäß hatte eine relativ hohe Beutedichte zur Folge.

Five generations of Ferrisia virgata (CKLL.) have been reared per year; singly on sprouting potato tubers, although the fifth generation was not completed because of cold weather. This method produces only parthenogenic females, while males and females may be produced by dense rearing. Copulation was never observed, while oviposition behaviour and hatching process were described. Eggs are deposited singly and the incubation period averages 2.11–2.62 hr. with no significant difference under various thermal conditions. Hatchability ranges from 96.2–99.1%. Total nymphal duration in females averages 43.2 and 92.6 days at 28.9 and 16.6°C., respectively, while that in males elapses 25.4 days at 25.1–26.5°CC. Duration of the three nymphal instars of females and the four ones in males are estimated in various generations. The differences in duration between generations and those between instars within each generation were highly significant. Rate of mortality during nymphal stadia in the autumn/winter generations is higher than that in the spring/summer ones; being 14.3–100 and 0–23%, respectively. Longevity of parthenogenic ovipositing and non‐ovipositing females as well as that of males is estimated. The total life period (from egg to adult death) averages 76.2–154.6 days in females opposite to 19–47 in males. Eggs laid by a female averages 64.1–78 eggs; producing 61.6–67.6 nymphs/female/life. Average number of eggs/female/day averages 3.4–4.5 eggs. Three hymenopterous parasites and five predators are found associated with F. virgata. However, numbers of these bioagents are considerably low compared to the relatively high population of the pest.

Rates of natural sickness and mortality among active larvae of Pectinophora gossypiella Saunders, found in cotton squares flowers and bolls throughout two active seasons (July‐September, 1974 and 1975) were very low: 0–0.6% sick and 3.5–9.4 dead. During the resting season, however, rate of natural sickness and mortality increased gradually from November till May. Throughout the two resting seasons 1973/74 and 1974/75, the respective average rates of healthy larvae were 54.4 and 57.8%, sick larvae carrying dermal brown lesions associated with pathogenic bacteria were 4.1 and 1.7%, larvae killed by the ectoparasitic mite Pyemotes herfsi 24.5 and 33.9%, larvae parasitized by Exeristes roborator 1.4 and 1.7%, larvae parasitized by Parasierola sp. 0.9 and 0.7%, predated larvae 1.3 and 2.0%, dead, soft‐bodied and v‐shaped larvae (mostly due to virus infection) 5.4 and 1.7%, dead larvae carrying dermal brown lesions 2 and 0.4%, and dead larvae showing no specific symptoms 5.6 and 0.1%. However, by the end of the resting season (in May), rate of mortality among resting larvae reached 80.4–96.8%, out of which 44.9–73.9% were killed by Pyemotes herfsi. Two pathogenic bacterial strains, Bacillus thuringiensis var. finitimus and B. cereus, were isolated from sick or dead resting larvae of P. gossypiella carrying dermal brown lesions. No significant correlation was found between the mortality rates of resting larvae, and the monthly averages of daily mean temperature or relative humidity. Zusammenfassung Untersuchungen über die Mortalität der Aktiv‐ und Ruhelarven von Pectinophora gossypiella Saund. (Lepidoptera, Gelechiidae) in Giza, Ägypten Der Anteil an Kranken und Gestorbenen unter den aktiven Larven von P. gossypiella innerhalb der Baumwollblüten und ‐kapseln war während der zwei Untersuchungsperioden (Juli‐September 1974 und 1975) mit 0–0,6% Kranken und 3,5–9,4% Toten sehr gering. Während der Ruheperiode (November‐Mai) stiegen jedoch die Raten fortwährend an auf folgende Werte: gesunde Larven 54,4 und 57,8%; kranke Larven mit braunen Hautlesionen (Bakteriosen) 4,1 und 1,7%; von der ektoparasitischen Milbe Pyemotes herfsi vernichtete Larven 24,5 und 33,9%; von der Schlupfwespe Exeristes roborator Parasitierte 1,4 und 1,7%; von der Schlupfwespe Parasierola sp. Parasitierte 0,9 und 0,7%; von Predatoren Gefressene 1,3 und 2,0%; tote, schlaffe und v‐gestaltige Larven (Virosen) 5,4 und 1,7%; tote Larven mit braunen Hautlesionen 2 und 0,4%; tote Larven ohne spezifische Symptome 5,6 und 0,1%. Am Ende der Ruheperiode (im Mai) erreichte die Sterblichkeit der Ruhelarven 80,4 und 96,8%, woran Pyemotes herfsi 44,9–73,9% Anteil hatte. Zwei pathogene Bakterienstämme wurden aus den kranken oder toten P. gossypiella‐Larven isoliert: Bacillus thuringiensis var. finitimus sowie Bacillus cereus. Zwischen der Sterblichkeit der Ruhelarven und den Witterungsbedingungen bestanden keine gesicherten Beziehungen.

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