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United States Department of Agriculture

Agricultural Research Service

Research Project: EPIDEMIOLOGY AND MANAGEMENT OF XYLELLA FASTIDIOSA (XF) AND OTHER EXOTIC AND INVASIVE DISEASES AND INSECT PESTS Title: Can insecticides protect citrus from HLB infection?

Authors
item Serikawa, Rosana -
item Rogers, Michael -
item Backus, Elaine
item Stelinski, Lukasz -

Submitted to: Citrus Industry
Publication Type: Trade Journal
Publication Acceptance Date: May 25, 2010
Publication Date: July 1, 2010
Citation: Serikawa, R., Rogers, M., Backus, E.A., Stelinski, L. 2010. Can insecticides protect citrus from HLB infection? Citrus Industry: July: 6-9.

Interpretive Summary: Use of insecticides for control of the Asian citrus psyllid is an important component of HLB management programs used by Florida citrus growers to slow disease spread. The rationale for insecticide use is to keep psyllid (vector) populations as low as possible to minimize the potential for pathogen spread. Previously, no studies have demonstrated that insecticides can prevent, or protect, a citrus tree from HLB. The present studies used electrical penetration graph (EPG) monitors to determine the effect of three insecticides, imidacloprid (Admire Pro), aldicarb (Temik) and fenpropathrin (Danitol), on psyllid feeding behavior. Results from these studies demonstrated that for the two soil-applied insecticides, imidacloprid reduced psyllid phloem feeding activities associated with pathogen transmission (acquisition and inoculation), but aldicarb did not have any effect on psyllid feeding behavior during the 18 hours in which psyllids were confined on treated plants. Rapid mortality of psyllid adults as a result of the application of the foliar insecticide fenpropathrin prevented any phloem feeding behaviors from occurring. The implications of these results for citrus growers are presented in terms of benefits of these insecticides for reducing psyllid populations as well as potential for preventing inoculation of citrus with the HLB pathogen.

Technical Abstract: Hunanglongbing (HLB), or citrus greening, is a lethal bacterial disease of citrus causing devastating yield losses in Florida and many other citrus-growing areas of the world. The presumptive bacterial agent, C. Liberibacter asiaticus, is vectored by an exotic, invasive insect, Asian citrus psyllid. HLB management programs used by Florida citrus growers heavily rely on insecticides to reduce vector feeding and/or kill vectors, thus minimizing the potential for pathogen spread within and between citrus groves. Previously, no studies have directly demonstrated that insecticides can protect a citrus tree from HLB. The present studies tested the effects of three insecticides, imidacloprid (Admire Pro), aldicarb (Temik), and fenpropathrin (Danitol) on psyllid feeding behavior using electrical penetration graph (EPG) monitors. Results showed that for the two soil-applied insecticides, imidacloprid reduced psyllid phloem feeding activities associated with pathogen acquisition and inoculation but aldicarb did not have any effect on psyllid feeding behavior during the 18 hours in which psyllids were confined on treated plants. In contrast, the foliar insecticide fenpropathrin caused such rapid mortality of psyllid adults that no phloem feeding behaviors occurred. Implications of these results for citrus growers are presented in terms of benefits of these insecticides for preventing inoculation of citrus with the HLB pathogen, in addition to reducing psyllid populations.

Last Modified: 10/19/2014
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