Translator Disclaimer
1 October 2003 Augmentative Releases of Metaphycus sp. nr flavus Against Citricola Scale on Oranges in the San Joaquin Valley of California: Are Early Releases Better Than Late Ones?
Author Affiliations +
Abstract

We conducted an augmentative release trial with the encyrtid parasitoid Metaphycus sp. nr flavus (Howard) against citricola scale, Coccus pseudomagniolarum (Kuwana), in three citrus orchards in the San Joaquin Valley of California. Three parasitoid release timings (14 October–13 November, 4 January–5 February, and 26 February–16 March; hereinafter “early,” “intermediate,” and “late”) were compared with a no-release check. Approximately 2,400 female parasitoids were released per central release tree. Late releases were associated with reduced scale survival on the release trees but no evidence of scale suppression was found on adjacent trees. Early and intermediate releases resulted in less pronounced scale suppression than late releases. Intermediate and late, but not early, releases were associated with an increase in the numbers of recovered female M. sp. nr flavus. Early releases, however, increased the numbers of recovered male Metaphycus spp. Thus, at the time of early releases, the scales may have been too small for the production of female parasitoids. A multiple regression model relating the degree of scale mortality in one orchard to the levels of recovered female Metaphycus helvolus (Compere), M. sp. nr flavus, or M. luteolus (Timberlake) (these latter two species are morphologically indistinguishable), and Coccophagus spp., suggested that the number of Coccophagus spp. females followed by M. helvolus females, were most strongly associated with scale mortality.

Heinrich Schweizer, Robert F. Luck, and Joseph G. Morse "Augmentative Releases of Metaphycus sp. nr flavus Against Citricola Scale on Oranges in the San Joaquin Valley of California: Are Early Releases Better Than Late Ones?," Journal of Economic Entomology 96(5), 1375-1387, (1 October 2003). https://doi.org/10.1603/0022-0493-96.5.1375
Received: 16 March 2001; Accepted: 1 February 2003; Published: 1 October 2003
JOURNAL ARTICLE
13 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top