Sugar and nectar feeding by Tamarixia radiata, parasitoid of Asian citrus psyllid (Diaphorina citri)

Asian citrus psyllid, Diaphorina citri, (ACP) vectors the causal agent of huanglongbing or citrus greening, a disease threatening citrus production worldwide.  A primary difficulty in executing effective area-wide management programs for ACP is the presence of host plants in areas where insecticidal control is problematic, such as residential areas and abandoned commercial groves.  To supress ACP populations in such areas, the major citrus-producing states (FL, CA, TX) have developed mass rearing and release programs for the exotic eulophid Tamarixia radiata.  Since T. radiata feeds on sugar, we are conducting laboratory studies to determine the types of sugars it will feed upon and its foraging behavior on flowers and extrafloral nectaries.  This is a first step towards developing a conservation biological program for this parasitoid in residential and commercial areas.  The movement of wasps on filter paper strips spotted with aqueous sugar solutions was arrested when they came into contact with sucrose as well as the honey dew sugars melizitose and raffinose.  We are evaluating a range of nectar and honeydew sugars at different concentrations.  The wasps readily located and fed on the nectaries of small flowers with exposed or partially exposed nectaries.  These included alyssum, buckwheat, and spotted spurge.  They failed to feed on flowers with nectaries obstructed by petals or hairs, such as coriander and frog fruit (Phyl nodiflora).  This suggests that only flowers with unobstructed nectaries are suitable nectar hosts for T. radiata.  Evaluations of other flowers and extrafloral nectaries is ongoing.