Crude Extracts and Alkaloids Derived from Ipomoea-Periglandula Symbiotic Association Cause Mortality of Asian Citrus Psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

Abstract

Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important economic pest of citrus crops because it vectors the causal pathogen of huanglongbing (HLB; aka citrus greening). Population suppression of D. citri with insecticides has been disproportionally relied on for HLB management and a greater diversity of more sustainable tools is needed. Periglandula spp. is a fungal endosymbiont (family Clavicipitaceae) that forms a mutualistic relationship with members of plants in family Convolvulaceae. This association results in the production of ergot alkaloids that were previously documented as having psyllicidal properties. We investigated the mortality and behavior of D. citri exposed to crude extracts from morning glories in the plant family Convolvulaceae, as well as synthetic ergot alkaloids. Nymphs and adults were exposed to the crude plant extracts from Periglandula positive species of Convolvulaceae, as well as five synthetic ergot alkaloids. Treatments were prepared by exposing clippings of citrus to 100 ng/µL of crude extract from Periglandula-positive species of Ipomoea (I. imperati, I. leptophylla, I. pandurata and I. tricolor), and Turbina corymbosa, and from one Periglandula-negative species (I. alba) (100 ng/µL). Mortality of adult and nymphal D. citri was significantly higher than the control after exposure to extracts from I. tricolor and I. imperati. The synthetic ergot alkaloids, lysergol (10–100 ng/µL), ergonovine maleate (100 ng/µL), agroclavine (10–100 ng/µL), and ergosine (10–100 ng/µL) increased mortality of D. citri nymphs, while ergosine (100 ng/µL) and agroclavine (100 ng/µL) increased mortality of adults compared to water controls. Fewer D. citri adults settled on plants treated with crude extracts or synthetic ergot alkaloids than on water controls at 48 h after release. D. citri that fed on citrus leaves treated with 10 ng/μL solution of crude extract from the Periglandula-positive species Ipomoea (I. imperati, I. leptophylla, I. pandurata, I. tricolor), and Turbina corymbosa excreted significantly less honeydew compared with a negative water control and extract from Periglandula-negative species (I. alba). Our results indicate that crude extracts and ergot alkaloids exhibit toxic and sub-lethal effects on D. citri that could be useful for management of this pest.

Phytochemical Profiling and Isolation of Bioactive Polyphenols From Ipomoea carnea

“…The analysis of the most effective AK-sF by UPLC/MS/MS indicated the presence of ergot alkaloid compounds (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54). Previous findings regarding AK-sF largely agreed with those recently stated [56]. They found that crude extracts derived from different morning glories (Ipomoea sp) related to the Convolvulaceae family as well as some pure ergot alkaloids related to these plants showed strong insecticidal activity against Diaphorina citri adults.…”

Evaluation of Artemisia absinthium L. Essential Oil as a Potential Novel Prophylactic against the Asian Citrus Psyllid Diaphorina citri Kuwayama

“…The management of D. citri has played a significant role in HLB dispersal in citrus groves. Eight to twelve insecticide applications are commonly practiced in one cropping season in major citrus-growing countries worldwide [9]. However, the massive and repetitive use of these synthetic insecticides results in environmental pollution and the development of resistance [9,10].…”

“…Eight to twelve insecticide applications are commonly practiced in one cropping season in major citrus-growing countries worldwide [9]. However, the massive and repetitive use of these synthetic insecticides results in environmental pollution and the development of resistance [9,10]. Therefore, there is a need to develop novel eco-friendly alternatives for managing D. citri.…”