Maternal Contribution of Candidatus Liberibacter asiaticus to Asian Citrus Psyllid (Hemiptera: Liviidae) Nymphs Through Oviposition Site Inoculation and Transovarial Transmission

Infected Adult ◽

Candidatus Liberibacter ◽

Abstract Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), transmits Candidatus Liberibacter asiaticus (Las), the bacterial pathogen putatively responsible for citrus huanglongbing. Multiple studies have shown psyllids acquire Las more frequently, and are more likely to inoculate susceptible plants, when they acquire Las as nymphs. Understanding the transmission of Las to nymphs is critical to the Las lifecycle. The objective of this study was to determine the transmission Las by female D. citri to their offspring. Two transmission pathways were quantified: horizontal transmission (acquisition of Las via feeding at the oviposition site) and vertical transmission (transovarial). Eggs of individual, infected females were transferred to an uninfected seedling to assess vertical transmission. In a second experiment, horizontal transmission was evaluated by replacing eggs laid by infected females with uninfected nymphs. Nymphs exposed to Las via horizontal transmission of the oviposition site were more likely to acquire Las than from vertical transmission. Las deposited in flush by an infected adult female feeding during oviposition was sufficient for infecting nymphs. Combined results of both experiments suggest that vertical transmission allows Las to spread in low amounts even when infected plant hosts are not available and that inoculation of the oviposition site provides a source of Las to developing nymphs via the plant phloem. These data support the hypothesis that transmission through infected plant material via maternal inoculation is a primary pathway of Las transmission between vector and host.

The Asian Citrus Psyllid Host Murraya koenigii Is Immune to Citrus Huanglongbing Pathogen ‘Candidatus Liberibacter asiaticus’

Phytopathology ◽

10.1094/phyto-01-18-0012-r ◽

2018 ◽

Vol 108 (9) ◽

pp. 1089-1094 ◽

Cited By ~ 6

Author(s):

Vitor H. Beloti ◽

Gustavo R. Alves ◽

Helvécio D. Coletta-Filho ◽

Pedro T. Yamamoto

Keyword(s):

Infected Plant ◽

Asian Citrus Psyllid ◽

Test Plant ◽

Insect Vector ◽

Murraya Koenigii ◽

Trap Crop ◽

Candidatus Liberibacter ◽

Citrus Huanglongbing ◽

The Asian citrus psyllid (ACP) Diaphorina citri, vector of ‘Candidatus Liberibacter asiaticus’ (CLas), the putative causal agent of citrus Huanglongbing (HLB), is controlled by application of insecticides, which, although effective, has resulted in serious biological imbalances. New management tools are needed, and the technique known as “trap crop” has been attracting attention. A potential plant for use as a trap crop in the management of the ACP is Murraya koenigii (curry leaf). However, for this plant to be used in the field, it needs to be attractive for the vector and must not harbor CLas. To verify the potential of curry leaf as trap crop for the management of HLB, we investigated the ability of D. citri to transmit CLas to M. koenigii, and to other test plants, including M. paniculata (orange jasmine) and cultivar Valencia sweet-orange seedlings. For the tests, the insects were reared on a symptomatic CLas-infected plant and allowed to feed on the three test plant species. The overall maximum transmission rate for the citrus seedlings was 83.3%, and for orange jasmine was 33.3%. Successful transmission of CLas by ACP to the curry-leaf seedlings was not observed, and it was treated as immune to CLas. Supported by the previous results that M. koenigii is attractive for ACP, these results indicate that curry leaf is an excellent candidate for use as a trap crop, to improve the management of the insect vector and consequently of HLB.

A Review of Huanglongbing (Citrus Greening) Management in Citrus Using Nutritional Approaches in China

Plant Health Progress ◽

10.1094/php-2010-1003-01-rv ◽

2011 ◽

Vol 12 (1) ◽

pp. 24 ◽

Cited By ~ 7

Author(s):

Yulu Xia ◽

Gecheng Ouyang ◽

Ronald A. Sequeira ◽

Yu Takeuchi ◽

Ignacio Baez ◽

...

Keyword(s):

Nutrient Management ◽

Field Survey ◽

Cultural Practices ◽

Sweet Orange ◽

Asian Citrus Psyllid ◽

Diaphorina Citri ◽

Candidatus Liberibacter ◽

Citrus Maxima ◽

The Asian form of huanglongbing (HLB) is caused by ‘Candidatus Liberibacter asiaticus (Las),’ a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama. Nutrient management, together with other cultural practices such as pruning and irrigation, for mitigation of the disease has been practiced in China for many years. Our literature review, field survey, and interviews with Chinese scientists and growers indicate that these cultural practices were generally ineffective for the disease management. However, a nutritional approach in conjunction with other cultural practices such as irrigation can maintain grove productivity for a certain time depending on the type of citrus species/cultivars, the age of the trees, the propagation method of the plants, the Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) population, and other factors. Symptomatic mature pommelo (Citrus maxima Merr) and sweet orange (C. sinensis L. Osbeck) plants can commonly survive and maintain a certain level of productivity for an additional 4 to 5 years, even longer assuming vigorous ACP control. Accepted for publication 27 June 2011. Published 3 October 2011.

Tracing Penicillin Movement in Citrus Plants Using Fluorescence-Labeled Penicillin

Antibiotics ◽

10.3390/antibiotics8040262 ◽

2019 ◽

Vol 8 (4) ◽

pp. 262

Author(s):

Nabil Killiny ◽

Pedro Gonzalez-Blanco ◽

Yulica Santos-Ortega ◽

Fuad Al-Rimawi ◽

Amit Levy ◽

...

Keyword(s):

Vascular Tissue ◽

Vascular System ◽

Citrus Greening ◽

Application Site ◽

Asian Citrus Psyllid ◽

Diaphorina Citri ◽

Citrus Industry ◽

Candidatus Liberibacter ◽

Huánglóngbìng (HLB), citrus greening, is one of the most destructive diseases of citrus plants worldwide. In North America, HLB is caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus and is transmitted by the Asian citrus psyllid, Diaphorina citri. No cure exists at present, and the use of antibiotics for the control of HLB has gained interest due to the significant losses to the citrus industry. Because of unsatisfactory results when using foliar applications of antibiotics, concerns were raised regarding the uptake and translocation of these materials within trees. We, therefore, investigated a method that allows us to study the movement of antibiotic materials in citrus plants. Herein, we utilized a fluorescence-labeled penicillin, BOCILLIN™ FL-Penicillin (FL-penicillin), to study the uptake and translocation of penicillin in citrus plants. FL-penicillin was applied by puncture to the stem of young citrus seedlings and was traced by using fluorescence microscopy. After application, we detected FL-penicillin in the leaves and in the stem xylem and phloem tissues above and below the application site in both intact and partially bark-girdled citrus seedlings, indicating that it is easily taken up and transported through the plant vascular system. In addition, we detected FL-penicillin in the gut of D. citri, which were allowed to feed on the treated plants, suggesting translocation of this molecule into the vascular tissue. We propose that the use of fluorescent-labeled molecules could be an effective tool for understanding the uptake and translocation of antibiotics and other macromolecules in plants and insects.