Deployment of organic insecticides and parasitoids for sustainable management of Asian citrus psyllid (Diaphorina citri)

Huanglongbing (HLB), also commonly known as citrus greening disease, is likely the most devastating disease of citrus.  The Asian citrus psyllid (ACP) vectors pathogens that cause HLB. Vector management is critical to reduce disease spread. The majority of research dedicated to protecting U.S. citrus from this vector disease complex has focused on treatments that are prohibited from use by organic standards. Consistent use of costly synthetic insecticides is resulting in ACP resistance and significant damage to beneficial insects leading to more incidences of secondary pest outbreaks. Consequently, we have initiated development of ACP control programs testing use of organic insecticides and release of Tamarixia radiata also suitable for conventional citrus and urban habitats. Monthly applications of an organic insecticide Pyganic (natural pyrethrum) with horticultural mineral oil (HMO, 435 oil) or insecticidal soap (M-pede) in November, December and January compared to a single spray of the synthetic pyrethroid Danitol (fenpropathrin) in January provided significant reduction in overwintering ACP. Significant suppression of ACP in organic citrus comparable with conventional citrus was also observed during the growing season with Entrust, (Spinosad), Grandevo (Chromobacterium subtsugae), MBI 206 (Burkholderia spp), 435 oil, M-pede and Pongamia oil. Parasitism 9-100% by T. radiata was observed in organic citrus. Monthly sprays of Pyganic with HMO or insecticidal soap in winter and organic insecticides with oils and soap and T. radiata in the growing season appear to be viable options for developing ACP management programs in organic citrus and area-wide.