Timothy A Ebert

Timothy A Ebert
University of Florida | UF · Department of Entomology and Nematology

PhD

About

67
Publications
476,614
Reads
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1,032
Citations
Citations since 2016
30 Research Items
642 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Introduction
Currently, I am working on the analysis of data generated through electrical penetration graph techniques. The goal is to understand Hemipteran feeding behavior. The immediate application is assessment of insecticide effects on Asian Citrus Psyllid (Diaphorina citri) feeding to determine if an insecticide will prevent contact with the phloem, and thereby stop disease acquisition and transmission. I also work on a variety of other projects as time permits.
Additional affiliations
March 2018 - present
University of Florida
Position
  • Researcher
November 2007 - present
University of Florida
Position
  • PostDoc Position
January 1997 - June 2004
The Ohio State University
Position
  • Research Associate II
Education
June 1990 - May 1994

Publications

Publications (67)
Conference Paper
Full-text available
Citrus greening disease [huanglongbing (HLB)] is a devastating disease caused by gram negative, phloem-limited, fastidious bacteria Candidatus Liberibacter spp. (Davis et al., 2008). HLB infects almost all the commercial cultivated citrus, causing a major loss of tree vigor, production, fruit development, and quality (Trivedi et al., 2010). An inte...
Article
Full-text available
The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae: Cicadellinae), is an introduced vector of the xylem-dwelling bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadaceae) in California. Once acquired, X. fastidiosa colonizes the functional foregut of the vector. Bacteria can be inoculated d...
Technical Report
Full-text available
Building a physical barrier around citrus trees or groves can prevent contact between trees and Asian citrus psyllids, the carrier of the pathogen that causes huanglongbing. This new 4-page article is for growers, scientists, and industries that are interested in this approach to protect citrus from huanglongbing. Written by Timothy A. Ebert, Arnol...
Article
Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), populations exhibit varying levels of resistance to several insecticide classes, including pyrethroids. Artificial laboratory selection was conducted to investigate mechanisms underlying fenpropathrin resistance. After ten generations of selection, the LC50 for fenpropathrin inc...
Article
Full-text available
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest that transmits phloem-limited, gram negative bacteria including Candidatus liberibacter asiaticus (Clas), causing huanglongbing. Management of this pest relies primarily on insecticides, such as the neonicotinoid imidacloprid, that may affect secondary pests...
Article
Full-text available
Huanglongbing is a citrus disease that reduces yield, crop quality, and eventually causes tree mortality. The putative causal agent, Candidatus Liberibacter asiaticus (Rhizobiales: Rhizobiaceae), is vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama. Disease management is largely through vector control, but the insect is developing pes...
Article
Full-text available
Candidatus Liberibacter asiaticus Jagoueix, Bové, and Garnier (Rhizobiales: Rhizobiaceae) is transmitted by the psyllid Diaphorina citri Kuwayama and putatively causes Huanglongbing disease in citrus. Huanglongbing has reduced yields by 68% relative to pre-disease yields in Florida. Disease management is partly through vector control. Understanding...
Article
Electropenetrography (EPG) has been used for many years to visualize unseen stylet probing behaviors of plant-feeding piercing-sucking insects, primarily hemipterans. Yet, EPG has not been extensively used with blood-feeding insects. In this study, an AC-DC electropenetrograph with variable input resistors (Ri), i.e., amplifier sensitivities, was u...
Article
Insecticide resistance is an increasing problem in citrus production. The Asian citrus psyllid, Diaphornia citri Kuwayama, is recognized as one of the most important citrus pests worldwide and it has developed resistance in areas where insecticides have been overused. The development of insecticide resistance is often associated with fitness costs...
Preprint
Full-text available
Candidatus Liberibacter asiaticus is vectored by the psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) and putatively causes Huanglongbing disease in citrus. Huanglongbing has reduced yields by 68% relative to pre-disease yields in Florida. Disease management is partly through vector control. Understanding vector biology is essential in this...
Poster
Full-text available
Huanglongbing is a disease of citrus that reduces yield, reduces yield quality, and eventually kills the citrus tree. The putative causal agent, Candidatus Liberibacter asiaticus, is vectored by the Asian citrus psyllid, Diaphorina citri. Disease management is through vector control. However, the insect is developing pesticide resistance, and insec...
Article
Full-text available
The invasive Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), is the primary vector of the phloem-infecting bacterium, Candidatus Liberibacter asiaticus. Candidatus L. asiaticus is the putative causal agent of Huanglongbing (HLB) disease, a destructive disease of Citrus. While many Citrus species are susceptible to D. citri probing and...
Article
Full-text available
Monitoring the health of Huanglongbing-affected citrus trees by following changes in leaf Candidatus Liberibacter asiaticus ( C Las) titer has an inherent element of imprecision because C Las titer varies considerably within the tree canopy and with calendar seasons. In addition, the destructive sampling method used to determine C Las titer entails...
Article
Full-text available
Insects can be effective vectors of plant diseases and this may result in billions of dollars in lost agricultural productivity. New, emerging or introduced diseases will continue to cause extensive damage in afflicted areas. Understanding how the vector acquires the pathogen and inoculates new hosts is critical in developing effective management s...
Article
Full-text available
Insect vector behavior and biology can be affected by pathogen-induced changes in the physiology and morphology of the host plant. Herein, we examined the temporal effects of Squash vein yellowing virus (family Potyviridae, genus Ipomovirus) infection on the settling, oviposition preference, and feeding behavior of its whitefly vector, Bemisia taba...
Article
Full-text available
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the vector of Candidatus Liberibacter asiaticus (CLas), the presumed cause of Huanglongbing (HLB) in citrus. Management strategies were developed in Florida that used soil-applied neonicotinoids to protect young trees. Despite the implementation of intense management progr...
Article
https://citrusindustry.net/2018/11/26/research-update-citrus-under-protective-screen/
Article
https://citrusindustry.net/2018/07/02/artificial-intelligence-detecting-citrus-pests-diseases-disorders/
Article
Electropenetrography a.k.a. electrical penetration graph or EPG is a rigorous technique for studying arthropod behavior. Essentially, the arthropod and host are part of an electrical circuit that generates patterns of voltage (waveforms), whose biological meanings are defined by correlation with histology and behavior. EPG is used for studying styl...
Article
Full-text available
Diaphorina citri is a major pest of citrus because it transmits Candidatus Liberibacter asiaticus, a phloem-limited bacterium that putatively causes Huanglongbing (HLB). The disease moves slowly through a tree, and the vector facilitates further within-tree movement via transmission of the pathogen. However, this only happens when D. citri stylets...
Article
Full-text available
In the Asian citrus psyllid (Diaphorina citri Kuwayama), learning facilitates host recognition and mate preference; however, it is unclear whether induced female oviposition preference occurs in this species. We investigated the influence of natal host experience on adult oviposition preference when reared on either 'Valencia' orange (Citrus x sine...
Article
Volume 83, no. 5, e03005-16, 2017, https://doi.org/10.1128/AEM.03005-16. Page 14: Reference 39 should read as follows. 39. Ghanim M, Fattah-Hosseini S, Levy A, Cilia M. 2016. Morphological abnormalities and cell death in the Asian citrus psyllid (Diaphorina citri) midgut associated with Candidatus Liberibacter asiaticus. Sci Rep 6:33418. https://...
Article
Full-text available
We sampled 526 dooryard, 18 varietal block, and 784 commercial citrus trees in Florida between May 2009 and Apr 2014 for eriophyoid mites including Diptilomiopus floridanus Craemer & Amrine, Aceria sheldoni (Ewing), Aculops pelekassi (Keifer), and Phyllocoptruta oleivora (Ashmead). In total, 1,423 D. floridanus individuals were collected from doory...
Article
Full-text available
For users running ODA software using Windows 7-10 operating systems we describe how to assign missing values via Excel, and we note that file names may consist of more than eight characters.
Article
Importance: Insect transmission of plant pathogenic bacteria involves a propagation and circulation of the bacteria within their vectors. The transmission process is complex and requires specific interactions at the molecular and biochemical levels. The growth of the plant pathogenic bacteria in the haemolymph of their vectors indicated that the h...
Article
Full-text available
The purpose of this article is to help new users to begin the process of using optimal data analysis 9ODA) software.
Article
Full-text available
Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a major pest of citrus production because it is the vector of Candidatus Liberibacter asiaticus (Rhizobiales: Rhizobiaceae), which causes Asiatic huanglongbing, a devastating disease of citrus. Understanding the probing and ingestion behavior of the vector is important in understanding pathogen tra...
Article
Full-text available
Adults, immatures and eggs of Tuckerella japonica (Ehara) were collected from unknown clones or varieties of Camellia sinensis (L.) O. Kuntze tea bushes in the Clemson University Farm, Coastal Research and Education Center, Charleston, South Carolina; from Assam hybrids in The Caw Caw Nature Preserve in Ravenel, SC; from C. sinensis and C. assamica...
Article
Full-text available
Monitoring feeding behaviors of insects whose piercing–sucking mouthparts are inserted into plant tissue is often done by making the insect part of an electronic circuit, using a technique called Electrical Penetration Graph, or electropenetrography (both abbreviated EPG). Fluctuating voltage signals in the circuit are graphed, and resulting wavefo...
Article
Full-text available
Host plant resistance is a practical and cost effective approach for growers to manage insect pests. Recently, three new sources of resistance in black raspberry (Rubus occidentalis; selections ORUS 3778-1, ORUS 3817-1, and ORUS 4109-1) against the large raspberry aphid, Amphorophora agathonica, were identified. We studied stages of host plant acce...
Article
Full-text available
A Skinner mercury vapor light trap was operated from 2001 through 2009 in a residential backyard to document biodiversity within the moth families Thyatiridae, Drepanidae, Geometridae, Mimallonidae, Apatelodidae, Lasiocampidae, Saturniidae, Sphingidae, Erebidae (including Lymantriinae and Arctiinae), Euteliidae, Nolidae, and Noctuidae. When making...
Data
Nightly moth captures in Wooster, Ohio and summaries of these data
Article
Full-text available
Huanglongbing (HLB) or citrus greening is a devastating disease of citrus. The gram-negative bacterium Candidatus Liberibacter asiaticus (Las) belonging to the alpha-proteobacteria is responsible for HLB in North America as well as in Asia. Currently, there is no cure for this disease. Early detection and quarantine of Las-infected trees are import...
Article
Full-text available
THIS IS THE ENTIRE ARTICLE Candidatus Liberibacter asiaticus (Las) causes the insect vectored disease Huanglongbing (HLB) in Citrus spp. In Florida, the disease rate has increased two-fold every year since 2005. Significant knowledge gaps exist in Las transmission and epidemiology. Sweet orange groves in central Florida were selected to study seaso...
Article
Full-text available
Our goal was to estimate seasonal changes in the proportion of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), carrying Candidatus Liberibacter asiaticus. Our approach was to test Asian citrus psyllid by using pooled samples. The initial question was about pool size and the consequences of choosing poorly. Assuming no loss i...
Article
Full-text available
The purpose of this investigation was to evaluate acquisition and inoculation (together, transmission) efficiency of Candidatus Liberibacter asiaticus (Las), the pathogen associated with citrus huanglongbing (HLB) by the Asian citrus psyllid, Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae). In laboratory studies, nymphs reared on Las infected pl...
Article
Full-text available
Abstract: This article summarizes findings of a survey of agricultural producers concerning their practices and attitudes regarding pesticide spray drift. The results reveal that just as the agricultural enterprises involved in the sample are diverse and complex, so too are the approaches that growers take to managing drift. Growers tend to use mul...
Article
Full-text available
This paper presents the results of two related studies concerning the aerial application of dispersants. The first study characterized the interactions of various sized Corexit 9500 and 9527 dispersant droplets with oil films of from 0.1 mm to 3.0 mm thickness. A film thickness of 0.1 mm was selected as the end point since this is the thinnest oil...
Article
Full-text available
Good pesticide stewardship requires understanding how pesticide applications work because how we apply pesticides influences their efficacy and their impact on the environment. This article describes how pesticides are applied to a field at the most basic level – that of individual droplets from a spray cloud. By using a worked example, this articl...
Article
Full-text available
Aquatic beetles in the families Dryopidae, Dytiscidae, Elmidae, Gyrinidae, Haliplidae, Hydrophilidae, Noteridae, Psephenidae, and Scirtidae were sampled at the Ravenna Training and Logistics (RTLS) site in northeast Ohio from 1999 through 2001. The site is a military base with restricted access, but military activities can cause considerable enviro...
Article
Full-text available
Natural plant products have been studied for potential use as in-hive fumigants for suppression of parasitic mites and other pests. A more direct application through direct feeding of bees would avoid problems with fumigant volatility in cold climates and provide a more systemic route of exposure for the target pest. However, there must be a balanc...
Article
Full-text available
Dead and downed ocotillos (Fouquieria splendens) are common in the Colorado Desert of southern California and pose a question concerning the life-span of adult plants that have been reported to be long-lived: if ocotillo is long-lived, decay rates must be very slow. Our study focused on decomposition and disintegration of above-ground ocotillo wood...
Article
Full-text available
Experiments on the biological consequences of differences in pesticide distribution include testing differences in application equipment, differences in formulation, and more direct tests of the influence of droplet size, droplet number, or application volume on efficacy for insecticides, herbicides, or fungicides applied as atomized sprays. While...
Article
Full-text available
A number of plants produce nectar or pollen that contains toxins which can adversely affect honey bees. Almond (Amygdalus communis L. (Rosaceae)) produces amygdalin, a toxic cyanoglycoside, in its nectar and pollen. Although beekeepers regard almond as a valuable nectar and pollen plant, and honey bees are deployed extensively for almond pollinatio...
Article
Three sprayers were evaluated for their affect on retention and efficacy: a carbon dioxide powered high-volume sprayer, a DRAMM coldfogger, and an Electrostatic Spraying Systems (ESS) sprayer with air-assistance. The active ingredients used were spinosad and azadirachtin. The plant canopy was constructed in the greenhouse using potted soybeans (Gly...
Article
Full-text available
Current theory governing the biological effectiveness of toxicants stresses the dose-response relationship and focuses on uniform toxicant distributions in the insect's environment. However, toxicants are seldom uniformly dispersed under field conditions. Toxicant distribution affects bioavailability, but the mechanics of such interactions is not w...
Conference Paper
Full-text available
The influence of calcium, iron, magnesium, other cations, and mixtures of cations on the activity of glyphosate and the interaction with pH is reviewed, discussed, and demonstrated with laboratory data. The strategy to overcome antagonistic effects of the cations via use of adjuvants is discussed and illustrated with data. The influence of calcium...
Article
Full-text available
Agricultural application of pesticides is often done by atomization of the active ingredient and a carrier fluid. This atomized fluid lands on a plant surface and creates a mosaic of treated and untreated patches that we define as deposit structure. This structure influences the biological effect of the pesticide if dose per unit time is a factor i...
Article
Full-text available
Application of pesticides through a hydraulic nozzle produces deposits on a plant surface which have a spatial structure with elements of deposit size, number per area, and toxin per deposit. To investigate the relative contributions of these elements to the interaction of deposit structure and toxicant efficacy, we used a stochastic cellular autom...
Article
Pesticide deposits have a spatial structure having elements of size, number per area and toxicant per deposit. To investigate the relative contributions of these elements to the efficacy of the deposit structure, we developed a bioassay using the cabbage looper (Trichoplusia ni), cabbage, and a soluble concentrate formulation of fipronil [(±)-5-ami...
Article
Full-text available
Morphometric data of Aphis gossypii Glover are used as a case study to illustrate the use of randomization tests. The application of randomization tests in morphological evaluation and identification of species is a powerful tool for characterizing populations and species. It offers the advantage of reducing our reliance on the robustness of more c...
Article
Full-text available
Pesticides must be applied to the target area uniformly. Uniformity of sprayer output is typically described by the coefficient of variation (CV) of the spray emitted. However, deposit size, number, and concentration interactions are overlooked when using this static. A measurement technique and alternative statistics, capable of documenting and se...
Article
Full-text available
Apple (Malus domestica Borkh.) leaves were sprayed to runoff using a selection of pesticides, and subsequent spray retention was evaluated by weight. Timing, cultivar, leaf surface, and leaf type significantly influenced spray retention. Spray retention correlated significantly and positively with leaf hair density. The importance of these differen...
Article
Full-text available
Aphis gossypii Glover is a destructive pest of over two dozen crops world wide. Damage to a few of these crops is due to direct feeding, but for most of these crops its impact is through its role as a virus vector.As expected, this has resulted in many articles dealing with methods of controlling this insect. The aphid has the ability to become res...
Article
Full-text available
Typescript (photocopy). Thesis (M.S.)--Colorado State University, 1990. Includes bibliographical references (leaves [36]-40).

Questions

Questions (13)
Question
I have the capacity to take samples on "n" days per year. I could take all the samples in the first "n" days, or I could spread them out in different ways over the interval. I am trying to think about how to describe that distribution so that I can focus on the best choices and describe that to others. I suspect that this is a common problem somewhere but I do not know the key words that might unlock the literature.

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Projects

Projects (8)
Project
I am trying to learn R. I hope to post code that others might find useful. The initial goal is to develop the tools needed to generate hacker data (fake data). This is not a search for websites or books on learning R. If there are other or better ways of getting the end result then I am happy to see that.
Archived project
These are the two papers that I worked on relating to this topic. My focus was on the analysis of the data.