Suppression of<i>Myllocerus undatus</i>(Coleoptera: Curculionidae) In Valencia Orange with Chlorpyrifos Sprays Directed at Ground and Foliage

Abstract

Myllocerus undatus Marshall (Coleoptera: Curculionidae) has been reported in Florida on numerous ornamental species and fruit crops, in which it causes damage to the foliage and possibly root systems (Thomas 2005; NPGA 2000; O'Brien et al. 2006). However, reports of its pest status and importance on citrus have not been published. At least 1 citrus grove manager in the Immokalee area in Collier Co., FL has been battling the weevil for 2 years in response to considerable foliar damage caused by M. undatus adults. At his request, we visited the grove and observed cumulative damage in several blocks of ^Valencia' orange, in which some hotspots were nearly defoliated. Numerous adults were found feeding on the leaves in the canopy of affected trees, concentrated near the trunk, and in branches with dense foliage. Adults were seen at the base of the trunk where they had presumably descended to oviposit and in considerable numbers on the orchard floor feeding on leaves of broadleaf weeds, especially Spanish needles, Bidens bipinnata L. (PAS & HAA, personal observations). On 2 May 2008, we examined the root systems and surrounding soil of 7 or 8 trees that have been removed due to Huanglongbing symptoms. Although no obvious root damage was observed and a single pharate M. undatus adult was found, the foliar damage alone was cause for con-