Phytoparasitica (1996) 24, 71-72
D. Hadar, M. Wysoki, David Rosen and D. Blumberg (1996)
Behavior of introduced parasitoids against the pyriform scale on avocado
Phytoparasitica 24 (1), 71-72
The third World Avocado Congress, October 22-27, 1995, Tel Aviv, Israel, lecture
Abstract: Since 1980 the pyriform scale, Protopulvinaria pyriformis (Cockerell), has been an important pest of avocado in Israel. Parasitoids of the pyriform scale have been introduced into Israel from South Africa, Kenya, Florida, California and Spain. Metaphycus swirskii Annecke and Mynhardt, initially the most abundant parasitoid, was soon replaced by Metaphycus stanleyi (Compere), a later introduction which is now the most abundant natural enemy of the pyriform scale. Metaphycus helvolus (Compere) also became established on avocado, but to a lesser extent and is now quite rare. Two hyperparasites, Pachyneuron concolor (Förster) and Marietta javensis (Howard), have an adverse effect on the effectiveness of Metaphycus spp. In some groves 70% of the total parasite fauna consist of these two hyperparasite species. The percentage of active primary parasitization increases in September, is high during winter, and peaks in May; it then declines in summer, when the parasitoids are hard to find. This is due to both climatic factors and encapsulation. Metaphycus spp. differ in the site, duration and rate of oviposition, in host marking, and in preference for host stages. M. helvolus oviposits in body margins of the pyriform scale, whereas M. stanleyi oviposits through the host's dorsum. The duration of oviposition is short (7 sec) in M. stanleyi and relatively long (68 sec) in M. helvolus; the former lays 13 eggs per hour, the latter only 3. M. stanleyi attacks mainly third-instar larvae and young females, whereas M. helvolus attacks also second instars, but may be repelled by the host's body movements.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Daniel Blumberg
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
classical biocontrol/new introduction
general biology - morphology - evolution
