Trials using Bacillus thuringiensis to control the olive moth, Prays oleae in Greece in 1976

Abstract

AbstractA Bacillus thuringiensis preparation (Dipel) was tested in the field to control larvae of the first generation of the olive moth Prays oleae on the flowers in 1976. Two trials were established during the period of olive bloom in May at Akrefnion (100 km north of Athens). One was of selected trees, treated as single‐tree plots with four different concentrations of B. thuringiensis in order to determine the lowest effective dose. For the second trial, blocks of trees were used treated with a single concentration in order to assess how far control of larvae in the first generation gave control of the succeding generation in the fruit. The results for the single tree plots show that concentrations of Bacillus tested from 5 times 106 to 20 times 106 IU/litre gave similarly good results. The effect of this strong suppression of the flower generation was however muted in the next generation on the fruit in the large plots. A difference however was recorded on the number of fruit with moth eggs between treated and untreated plots and a higher number of fruit was counted on the treated trees in mid‐summer as well.ZusammenfassungZur Bestimmung des Verhältnisses zwischen Nahrungsstoffeintrag und Abfallablagerung bei 2 grasschneidenden Ameisenarten (Hym., Attini)Es wurde für 2 Arten aus 2 Gattungen von grasschneidenden Ameisen der sogen. Konversionsfaktor bestimmt, der das Verhältnis zwischen dem Nahrungsstoffeintrag in das Nest und der Abfallablagerung im Nest repräsentiert. Die Faktoren für die beiden Arten (1,5–3,3 für Atta vollenweideri und 1,8 für Acromyrmex landolti) unterscheiden sich um das 4‐ bis 8fache von dem früher von Autuori (1947) für Atta sexdens gefundenen Wert von 12,4. Auf Grund dieser Diskrepanz ist anzunehmen, daß der von Atta‐Arten bisher angenommene Schaden erheblich überschatzt wurde.