Antifeedant and sublethal effects of imidacloprid on Asian citrus psyllid, Diaphorina citri.
BACKGROUND
Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, transmits the causal bacteria of the devastating citrus disease huanglongbing (HLB). Because of the variation in spatial and temporal uptake and systemic distribution of imidacloprid applied to citrus trees and its degradation over time in citrus trees, ACP adults and nymphs are exposed to concentrations that may not cause immediate mortality but rather sublethal effects. The objective of this laboratory study was to determine the effects of sublethal concentrations of imidacloprid on ACP life stages.


RESULTS
Feeding by ACP adults and nymphs on plants treated daily with a sublethal concentration (0.1 microg mL(-1)) of imidacloprid significantly decreased adult longevity (8 days), fecundity (33%) and fertility (6%), as well as nymph survival (12%) and developmental rate compared with untreated controls. The magnitude of these negative effects was directly related to exposure duration and concentration. Furthermore, ACP adults that fed on citrus leaves treated systemically with lethal and sublethal concentrations of imidacloprid excreted significantly less honeydew (7-94%) compared with controls in a concentration-dependent manner suggesting antifeedant activity of imidacloprid.


CONCLUSIONS
Sublethal concentrations of imidacloprid negatively affect development, reproduction, survival and longevity of ACP, which likely contributes to population reductions over time. Also, reduced feeding by ACP adults on plants treated with sublethal concentrations of imidacloprid may potentially decrease the capacity of ACP to successfully acquire and transmit the HLB causal pathogen.
Entomology and Nematology Department, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA. drboina@ufl.edu
Dhana Raj
DR
Boina
Ebenezer O
EO
Onagbola
Masoud
M
Salyani
Lukasz L
LL
Stelinski
D000821:Animal Feed; D000818:Animals; D001681:Biological Assay; D002957:Citrus / Q000469:parasitology*; D005260:Female; D005298:Fertility / Q000187:drug effects; D006430:Hemiptera / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D007093:Imidazoles / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D008136:Longevity / Q000187:drug effects; D008297:Male; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000494:pharmacology*; D009758:Nymph / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018515:Plant Leaves; D013217:Starvation; D015996:Survival Rate
D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid