Publications by Oscar E Liburd
Journal Applied Entomology, 2020
The spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive pest of many fruit crop... more The spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive pest of many fruit crops throughout North America, South America and Europe. The presence of this destructive pest has led to an increase in the number of insecticide applications. While conventional growers have an arsenal of different insecticides at
Crop protection, 2020
Flower thrips (primarily Frankliniella spp.) can be significant strawberry pests, and recently in... more Flower thrips (primarily Frankliniella spp.) can be significant strawberry pests, and recently in Florida, Scirtothrips dorsalis Hood has become an established, early-season, foliar pest. Insecticides that were used for flower thrips management are now also used for S. dorsalis, resulting in the need to evaluate newer insecticides in order to diversify rotations and mitigate overuse of insecticides with the same mode-of-action. We evaluated 10 and 12 season-long insecticide programs in field plots in central Florida during the 2016-2017 and 2017-2018 winter strawberry seasons, respectively. We found that most programs reduced thrips populations and strawberry injury due to thrips feeding, while having limited effects on Orius spp., a primary thrips predator. An early season application of chlorantraniliprole þ thiamethoxam, commonly used for other strawberry pests, reduced S. dorsalis populations and strawberry injury, although S. dorsalis populations were relatively low in both study years. When repeat applications of the same insecticide were made throughout the growing season, cyantraniliprole was nearly as effective as spinetoram against Frankliniella spp., while tolfenpyrad and sulfoxaflor did not perform as well. Flupyradifurone was as effective as acetamiprid when used as a follow-up application to spinetoram or cyantraniliprole. Programs including or entirely composed of OMRI-listed insecticides for organic production were not as effective as conventional insecticide programs, with only spinosad providing acceptable thrips control. In conclusion, spinetoram, acetamiprid and spinosad were confirmed to be effective against thrips and can be used as the backbone of rotation programs in conventional and organic strawberry production systems. Diamide insecticides were effective when used repeatedly and in rotation, while flupyradifurone and flonicamid may be used when follow-up applications are needed. Continued research is critical for fine-tuning insecticide programs, with a focus on testing against high S. dorsalis populations in early-planted strawberries and on developing effective sampling methods to optimize timing and reduce the number of applications.
Environmental Entomology
Tomato chlorotic spot virus (TCSV) is an orthotospovirus that causes a devastating disease in tom... more Tomato chlorotic spot virus (TCSV) is an orthotospovirus that causes a devastating disease in tomato (Lycopersicon esculentum Miller). TCSV emerged recently in South Florida. Studies were conducted in three commercial tomato fields in Miami-Dade County, Florida during the vegetable-growing seasons from October to April in 2015 through 2017. Each year, data were collected at 3, 6, and 9 wk after transplanting at various distances from the edges of each fields. Based on 3 yr total samples, three species of thrips were commonly observed melon thrips, Thrips palmi Karny (62.16 ± 0.79%), being the most abundant species followed by common blossom thrips, Frankliniella schultzei Trybom (21.55 ± 0.66%), and western flower thrips, Frankliniella occidentalis (Pergande) (16.26 ± 0.61%). Abundance of all thrips and TCSV infected plants was high at the edge of a tomato field 3 wk after transplanting with significantly fewer infected plants toward the center of the field. The distribution patterns of thrips and TCSV in various fields were mostly regular and aggregated across the sampling dates during the study period. Abundance of TCSV symptomatic plants and thrips species was high at the edge of the field and increased over time. The number of samples required to accurately determine population density of thrips was calculated by using three precision levels (0.10, 0.20, 0.30) at three predetermined densities of thrips (0.10, 0.20, and 0.40 per sample). This information will provide guidelines to growers, crop protection personnel, agricultural scouts, and researchers to develop a sustainable thrips and tospovirus management program.
Insects, 2020
Biological control has been the most commonly researched control tactic within fruit fly manageme... more Biological control has been the most commonly researched control tactic within fruit fly management programs, and parasitoids have been the main natural enemies used against pestiferous fruit fly species. In view of this fact, it is important to highlight and compile the data on parasitoids with a certain frequency, aiming to facilitate the knowledge of all the researchers. Information regarding the activities of parasitoids and predators on pestiferous fruit flies in the Americas is limited; therefore, this study aimed to compile the diversity of parasitoids and predators associated with tephritid fruit flies, as well as providing the scientific evidence about the use of parasitoids and predators as biological control agents for fruit flies im the Americas and Hawaii.
Journal of Economic Entomology, 2021
The twospotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae), is a key pest of s... more The twospotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae), is a key pest of strawberries and many other crops worldwide. Cover cropping, selecting tolerant or resistant cultivars, and biological control are important strategies of an organic management plan. In this study, we examined the effect of summer cover crops and strawberry cultivars on populations of T. urticae and a commercially available predatory mite, Neoseiulus californicus McGregor (Acari: Phytoseiidae), commonly used for T. urticae management in Florida. In the 2013-2014 season, four cover crops and eight strawberry cultivars were screened at the research station and on a commercial organic strawberry farm. The following season, the most promising cover crops (sunn hemp and hairy indigo) and cultivars, 'Sensation', 'Strawberry Festival', and 'Winterstar' were tested at the research station and on two small organic farms.
Environmental Entomology, 2021
Plastic mulch of different colors and ultraviolet (UV) reflectivity individually or combined with... more Plastic mulch of different colors and ultraviolet (UV) reflectivity individually or combined with released arthropod predators is an important component of an integrated pest management strategy. In 2015 and 2016, we evaluated the density and within-plant distribution of a released predatory mite, Amblyseius swirskii Athius-Henriot (Acari: Phytoseiidae) in snap bean (Phaseolus vulgaris L.), cucumber (Cucumis sativus L.), yellow squash (Cucurbita pepo L.), eggplant (Solanum melongena L.), Jalapeno pepper (Capsicum annuum L.), and tomato (Solanum lycopersicum L.) grown on different plastic mulches. The mulch treatments evaluated were: metalized top and black bottom, metalized top and white bottom, black-on-black, black-on-white, white-on-black, and bare soil with no mulch. Crop species had a significant effect on the density of A. swirskii. Eggplant and cucumber had higher numbers of A. swirskii than the other crops tested in 2015. In 2016, the density of A. swirskii was higher on eggplant than on cucumber. There was a variation in the distribution of A. swirskii in different strata of the plant canopies with the highest number in the bottom stratum of each crop, which was positively correlated with the population of Thrips palmi Karny (Thysanoptera: Thripidae). Mulch type had no effect on the density or distribution of A. swirskii in any strata of any of the crops tested. The results of this study indicate that releasing A. swirskii is compatible with the use of UV-reflective mulch. This information about host preference and within-plant distribution of A. swirskii should be of value in pest management programs for the crops studied.
Arthropod Management Tests, 2001
Journal of Economic Entomology, 2011
Grape root borer, Vitacea polistiformis (Harris) (Lepidoptera: Sesiidae), is an important pest of... more Grape root borer, Vitacea polistiformis (Harris) (Lepidoptera: Sesiidae), is an important pest of cultivated grapes (Vitis spp.) in the eastern United States from Michigan to Florida. There are few registered insecticides for control of this pest, and their efÞcacy is limited. Pheromone-based mating disruption is a potential alternative to insecticides for management of V. polistiformis. Waxbased Specialized Pheromone & Lure Application Technology (SPLAT) was tested as a mating disruption method. Deployment densities of 150 dispensers per ha dosed with 5 mg of V. polistiformis pheromone were sufÞcient to achieve 95% mating disruption during a 7-wk trapping period. The disruption mechanism was determined to be competitive attraction. The release rate of pheromone from these dispensers was quantiÞed to be approximately linear, 77.4 g/g SPLAT/d. At this release rate, a minimum initial load of 5.4 mg of pheromone per dispenser would be needed to maintain disruption over a 9 Ð10-wk V. polistiformis ßight season, Ϸ19 August to 21 October in central Florida. It should be noted, however, that the main pheromone component alone, (E,Z)-2,13-octadecadienyl acetate (ODDA), was effective (presumably by a noncompetitive mechanism) at higher loads per area of crop. Due to the cost of synthesis of highly pure isomers of the V. polistiformis pheromone components, mating disruption of V. polistiformis may be more practical with higher doses of commercially produced Zeuzera pyrina L.
Environmental entomology, 2005
Field trapping studies were conducted to determine whether feral blueberry maggot flies, Rhagolet... more Field trapping studies were conducted to determine whether feral blueberry maggot flies, Rhagoletis mendax Curran, and Eastern cherry fruit flies, R. cingulata (Loew), respond to natal host-fruit volatiles. Subsequent ...
EDIS
ENY-847, a 3-page illustrated factsheet by O. E. Liburd and T. W. Nyoike, provides information ab... more ENY-847, a 3-page illustrated factsheet by O. E. Liburd and T. W. Nyoike, provides information about aphids, their biology and lifecycle, damage, monitoring and management strategies for sustainable agriculture. Includes references. Published by UF Department of Entomology and Nematology, January 2008.
Crop Protection
The grape root borer (GRB), Vitacea polistiformis (Harris), is a significant pest of grapes (Viti... more The grape root borer (GRB), Vitacea polistiformis (Harris), is a significant pest of grapes (Vitis spp.) throughout parts of the eastern United States. Early detection and implementation of management tactics can prevent economic losses and vine death. The establishment of an effective monitoring program requires the deployment of pheromone baited traps in vineyards and native wild grapes. An understanding of the spatial distribution of GRB infestations is critical for the development of sampling plans and for implementing management decisions. Wing traps baited with synthetic GRB sex pheromones (99:1 blend of (E,Z)-2,13-ODDA and Z,Z-3,13-ODDA) were deployed in commercial vineyards and surrounding woodlands in wild grapes to monitor GRB abundance and distribution. In addition, pheromone-baited wing traps were placed at low, medium, and high positions (0.5 m–2 m above the ground) on the grapevine trellis in commercial vineyards to evaluate the effect of trap height on the number of GRB captured. Traps placed in the cultivated vineyard had consistently higher counts of GRB compared with traps along the vineyard edge and in the wild grapes in the woodland. The pheromone-baited traps placed on the highest trellis wire caught more GRB adults than traps placed at the lowest position on the bottom trellis wire. Therefore, we recommend to place traps at approximately 2 m in the upper grapevine canopy early in the season before flight of GRB moth begins in order to aid in the timing and implementation of management tactics.
The grape root borer (GRB), Vitacea polistiformis (Harris), is a significant pest of grapes (Viti... more The grape root borer (GRB), Vitacea polistiformis (Harris), is a significant pest of grapes (Vitis spp.) throughout parts of the eastern United States. Early detection and implementation of management tactics can prevent economic losses and vine death. The establishment of an effective monitoring program requires the deployment of pheromone baited traps in vineyards and native wild grapes. An understanding of the spatial distribution of GRB infestations is critical for the development of sampling plans and for implementing management decisions. Wing traps baited with synthetic GRB sex pheromones (99:1 blend of (E,Z)-2,13-ODDA and Z,Z-3,13-ODDA) were deployed in commercial vineyards and surrounding woodlands in wild grapes to monitor GRB abundance and distribution. In addition, pheromone-baited wing traps were placed at low, medium, and high positions (0.5 m–2 m above the ground) on the grapevine trellis in commercial vineyards to evaluate the effect of trap height on the number of G...
Journal of Economic Entomology, 2016
Organic zucchini squash is a high-value vegetable crop in Florida and potential exists to expand ... more Organic zucchini squash is a high-value vegetable crop in Florida and potential exists to expand its production throughout the state. A lack of knowledge on the effectiveness of organic products and their integration with natural enemies is an important constraint to the regulation of pest populations in organic squash production in Florida. The objectives of this study were to evaluate the effect of insecticides labeled for organic production that can be used for management of Bemisia tabaci (Gennadius) biotype B, on organically grown squash; and to determine the effects of the most efficient insecticides on a key natural enemy, Delphastus catalinae (Horn). Experiments were conducted in the greenhouse in exclusion cages. The first experiment compared the effects of four bioinsecticides on whitefly densities. Insecticides include 1) AzaSol (azadirachtin), 2) PyGanic EC 1.4 (pyrethrin), 3) M-Pede (insecticidal soap), and 4) Entrust (spinosad). The second experiment investigated the effects of bioinsecticides on D. catalinae Treatment effectiveness was evaluated 1, 3, and 5 d posttreatment. PyGanic and M-Pede were highly effective in controlling whitefly populations on organic squash, while moderate control was provided by AzaSol and there was no control provided by Entrust. PyGanic and M-Pede treatments reduced D. catalinae populations when adults were released 1 d post pesticide application. However, when adults were released 5 d post application, there was no reduction. The importance of using bioinsecticides in combination with natural enemies to regulate pest populations in organic cropping systems is discussed.
Pest Management Science, 2015
Zucchini squash, Cucurbita pepo L., is an important vegetable crop in Florida. Physiological diso... more Zucchini squash, Cucurbita pepo L., is an important vegetable crop in Florida. Physiological disorders and insect-transmitted diseases are major problems for squash growers in semi-tropical regions around the world. Bemisia tabaci (Gennadius) biotype B is a significant whitefly pest and is largely responsible for transmitting viruses and causing physiological disorders in squash. Several studies have shown that whitefly populations are reduced when crops are interplanted with non-host cover crops or mulches. The aim of the present study was to determine how the presence of buckwheat, Fagopyrum esculentum Moench, and a key predator, Delphastus catalinae (Horn), affect whitefly colonization on squash. Whitefly densities were higher on squash than on buckwheat. The introduction of D. catalinae on squash significantly reduced whitefly populations. Overall, there were higher densities of D. catalinae on squash where the whitefly pest was more concentrated compared with buckwheat. The study provided preliminary evidence that D. catalinae, when used in conjunction with buckwheat as a living mulch, may aid in reducing whiteflies in squash. This greenhouse experiment highlights the need to investigate a multitactic approach of intercropping buckwheat with squash and the incorporation of D. catalinae in the field to manage populations of whiteflies and whitefly-transmitted diseases. © 2015 Society of Chemical Industry.
Agroecology and Sustainable Food Systems, 2016
Aphids and whiteflies are significant direct pests of squash and transmit plant viruses. The use ... more Aphids and whiteflies are significant direct pests of squash and transmit plant viruses. The use of buckwheat, Fagopyrum esculentum Moench, as a living mulch intercropped with squash has been shown to reduce insect pests and diseases while increasing the abundance of beneficial insects; however, how to best implement buckwheat in squash fields has not been determined. Several arrangements of intercropping buckwheat and squash were evaluated, with and without the introduction of a natural enemy, Delphastus catalinae (Horn), to find a tactic that reduces insect pests and disease incidence while increasing marketable yield. Intercropping treatments included planting strips of buckwheat alternating on either side of the squash with and without D. catalinae (arrangement A), planting buckwheat in the middle of squash planted on both sides of the bed with and without D. catalinae (arrangement B), buckwheat planted on both sides of squash (arrangement C), and a bare ground treatment. Aphid densities and insect-transmitted viruses were reduced, while natural enemies were more abundant, in buckwheat treatments compared with bare ground treatments. Plant size was reduced in intercropping arrangements B and C compared with arrangement A. Marketable yields were not different between the bare ground treatment and buckwheat arrangements A and B.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution author... more The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations.
Aphids (Hemiptera: Aphididae) are minute pear-shaped, soft-bodied insects. Their reproductive pot... more Aphids (Hemiptera: Aphididae) are minute pear-shaped, soft-bodied insects. Their reproductive potential, salivary secretions, and ability to transmit viral diseases make them the most potent and worldwide enemies of many crops. There are approximately 4,400 aphid species in the world (Blackman and Eastop 1994). Several species can be found on cucurbits. Three species that can colonize members of the Cucurbitaceae family
The mission of the Center for Sustainable and Organic Food Systems at the University of Florida i... more The mission of the Center for Sustainable and Organic Food Systems at the University of Florida is to assist in the development of sustainable and organic food systems, with an emphasis on local and regional systems. One of the ways of so doing has been to facilitate collaboration among researchers in complementary fields to form interdisciplinary teams that address problems facing our stakeholders. In 2012, a team with expertise ranging from the biological sciences of entomology, horticulture and weed science to social sciences related to rural community development and food and resource economics coalesced to prepare a research proposal. Addressed at developing organic strawberry cropping systems that are more environmentally and economically sustainable and are resilient to weeds, pests, and diseases, the proposal targeted the USDA NIFA Organic Research and Extension Initiative (OREI) program and was highly regarded but not funded. In an effort to increase the likelihood of obtai...
Encyclopedia of Entomology, 2008
Encyclopedia of Entomology, 2008
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Publications by Oscar E Liburd