Compatibility and efficacy of Isaria fumosorosea with horticultural oils for mitigation of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

Authors: KUMAR, VIVEK - University Of Florida; AVERY, PASCO - University Of Florida; AHMED, JUTHI - University Of Florida; CAVE, RON - University Of Florida; McKenzie, Cindy; OSBORNE, LANCE - University Of Florida

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2017
Publication Date: 10/31/2017
Citation: Kumar, V., Avery, P., Ahmed, J., Cave, R., McKenzie, C.L., Osborne, L.S. 2017. Compatibility and efficacy of Isaria fumosorosea with horticultural oils for mitigation of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). Insects. 8:119. doi.org/10.3390/insects.8040119. https://doi.org/10.3390/insects.8040119
DOI: https://doi.org/10.3390/insects.8040119

Interpretive Summary: The broad spectrum utility of refined petroleum oils against arthropod pests and pathogens of economic importance make horticultural oils a valuable tool for growers to combat various pest problems in citrus production systems. With the objective to integrate the biopesticide Isaria fumosorosea into the current management program of Asian citrus psyllid, we evaluated the compatibility of selected petroleum oils with Isaria fumosorosea and assessed the efficacy of mixed treatments against the psyllid. None of the oil treatments tested had a negative impact on Isaria fumosorosea viability and growth. Laboratory bioassay results indicated that petroleum oil treatments containing Orchex, Sun Pure, Conoco Blend 1, Conoco Blend 2 and JMS enhanced the efficacy of Isaria fumosorosea and significantly reduced the survivability of the psyllid. Results of the study are significant in the view of the additive effect of the petroleum oils on the performance of Isaria fumosorosea. Because the oils and the entomopathogenic fungi are considered safe to non-target organisms including natural enemies, tested mixed treatments would encourage adoption of alternative management practices in citrus production, and help retention of effective chemistries for a longer period in the marketplace.

Technical Abstract: Horticultural oils are an important component of integrated management programs of several phytophagous arthropods, and pathogens affecting fruit, ornamental and vegetables in greenhouse and field production systems. Although effective against the target pest, their incompatibility with biological control agents can compromise efforts to develop eco-friendly management programs for important agricultural pests. In the current study, we assessed the effect of selected refined petroleum oils used in citrus and other horticultural crops on a biopesticide containing the entomopathogenic fungi, Isaria fumosorosea (PFR-97) under laboratory conditions. Further, we evaluated the combined efficacy of petroleum oils and Isaria fumosorosea against Asian citrus psyllid Diaphorina citri (Hemiptera: Psylloidea), a major pest of citrus in Florida. All five (Orchex, Sun Pure, Conoco Blend 1, Conoco Blend 2 and JMS) petroleum oil treatments were compatible with Isaria fumosorosea blastospores, as none of them were found affecting Isaria fumosorosea colony forming units, and radial fungal growth measured at 3, 6, 9 and 12 days post-inoculation. All the mixed treatments performed better than the Isaria fumosorosea alone treatment against Diaphorina citri, where highest mean survival time of Diahorina citri was 12.5 ± 0.73 days. No significant differences in the Diaphorina citri survival time and Isaria fumosorosea growth (fungal development index) on dead cadavers was observed among Orchex, Sun Pure, Conoco Blend 2 and JMS. Results indicated that horticultural oils in combination with Isaria fumosorosea can offer citrus growers an alternate for integrating into their current management programs while battling against Diaphorina citri in Florida citrus production systems.