Entomology: Personnel
Entomology Faculty
John R. RubersonProfessor of Entomology Contact InformationAddress: Department of Entomology Phone: 229-386-3374 |
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Research Overview
Our lab’s broad research emphasis is on the biological control of insect pests in cropping systems using predators and parasitoids. In particular, the primary objective of our research is to develop biological control information and practices that can be used in row crop and vegetable systems to manage pests in a more sustainable manner than unilateral reliance on pesticides. We concentrate on several key areas of research:
Ecology and Life Histories of Predators and Parasitoids.
Our life-history studies emphasize significant life-history elements that are important for the function and persistence of natural enemies. The ability to integrate natural enemies effectively into pest management programs relies heavily on an understanding of the ecology and behavior of relevant natural enemies. We have focused in two areas: diapause and feeding ecology. Our diapause work emphasizes ecological elements of diapause in an effort to better anticipate the timing of overwintering events (such as initiation of overwintering in the autumn and resumption of activity in the spring) in important predators. These data give us critical insights into timing of predator activity, overwintering resource needs, and seasonal constraints on survival. Our studies of feeding ecology have focused on the location of hosts/prey and the role of food decisions (food quality, plant versus animal) in the life histories of important omnivorous predators, such as predatory bugs, and parasitoids.
Examples of Recent Publications:
Ruberson, JR, YJ Shen & TJ Kring. 2000. Photoperiodic sensitivity and diapause in the predator Orius insidiosus (Heteroptera: Anthocoridae). Ann. Entomol. Soc. Am. 93: 1123-1130. PDF file
Ruberson, JR, KV Yeargan & BL Newton. 2001. Variation in diapause responses between geographic populations of the predator Geocoris punctipes (Heteroptera: Geocoridae). Ann. Entomol. Soc. Am. 94: 116-122. PDF file
Torres, JB, CSA Silva-Torres & JR Ruberson. 2004. Effect of two prey types on life history characteristics and predation rate of Geocoris floridanus (Heteroptera: Geocoridae). Environ. Entomol. 33: 964-974. PDF file
Silva-Torres, CSA, RJ Matthews & JR Ruberson. 2005. Role of olfactory cues in host finding by Melittobia digitata Dahms (Hymenoptera: Eulophidae), a parasitoid of solitary wasps and bees. Ann. Entomol. Soc. Am. 98(4): 595-600.
Silva-Torres, CSA, RJ Matthews & JR Ruberson. 2005. Role of chemical cues and natal rearing effect in host recognition by the parasitic wasp Melittobia digitata. Entomological Science 8: 355-362. PDF file
Integration of Biological Control with Pest Management Practices.
The efficacy of natural enemies in cropping systems is heavily influenced by other management practices applied to the system. Effectively incorporating biological control into integrated pest management strategies requires that we understand how management practices will influence the performance of the natural enemies. This is particularly true for conservation biological control, which relies chiefly on naturally-occurring natural enemies. In this context, our lab has concentrated on the interactions of biological control with (1) insecticides, (2) Bt-transgenic cotton, and (3) tillage.
Insecticides. Our work with insecticides concentrates on determining lethal and sublethal effects of novel insecticides on selected predators and parasitoids. These studies provide growers, consultants, and extension professionals with information regarding nontarget effects of new insecticides which can improve insecticide use while reducing risks of secondary pest outbreaks because of elimination of natural enemies. These results also assist regulators in assigning risk to an experimental insecticide during the assessment process.
Bt-transgenic cotton. Genetically-modified crops have raised a number of concerns, one of which is their impact on natural enemies in those crops, and the ability of enemies in those crops to function. Our studies address this concern in cotton, concentrating on predators. We have documented the lack of impact of Bt-transgenic cotton on insect predator populations and individuals living in the plant canopy and to some extent on the soil surface, although there is some movement of the Bt toxin from the plants through herbivores into a few predator species.
Tillage. Tillage practices are being modified as there is an increasing emphasis on the maintenance of soil quality and health. As a result, conservation tillage in various forms is being increasingly practiced in crop systems. Conservation tillage leaves residue on the soil surface, and also modifies the soil structure in ways that can affect organisms living in and on the soil. Our studies seek to characterize the pest and natural enemy populations and activity in cotton and vegetables when conservation tillage is practiced so that growers will know what types of insects and problems or solutions to expect if they adopt conservation tillage.
Examples of Recent Publications:
Ruberson, JR, H Nemoto & Y Hirose. 1998. Pesticides and conservation of natural enemies in pest management. In: P. Barbosa (ed.), Conservation Biological Control, pp. 207-220. Academic Press, New York.
Obrycki, JJ, JR Ruberson & JE Losey. 2004. Interactions between natural enemies and transgenic insecticidal crops. In: LE Ehler, R Sforza and T Mateille (eds.), Genetics, Evolution and Biological Control, pp. 183-206. CABI Publishing, Wallingford, Oxon, UK.
Torres, JB & JR Ruberson. 2004. Toxicity of thiamethoxam and imidacloprid to Podisus nigrispinus (Dallas)(Heteroptera: Pentatomidae) nymphs associated with aphid and whitefly control in cotton. Neotropical Entomology 33: 99-106. PDF file
Torres, JB & JR Ruberson. 2005. Canopy- and ground-dwelling predatory arthropods in Bt and non-Bt cotton fields: patterns and mechanisms. Environ. Entomol. 34: 1242-1256.
Nusawardani, T, JR Ruberson, JJ Obrycki & BC Bonning. 2005. Effects of a protease-expressing recombinant baculovirus insecticide on the parasitoid Cotesia marginiventris (Cresson). Biological Control 35: 46-54. PDF file
Torres, JB, JR Ruberson & MJ Adang. 2006. Expression of Bacillus thuringiensis Cry1Ac protein in cotton plants, acquisition by pests and predators: a tritrophic analysis. Agricultural and Forest Entomology 8: 191-202. PDF file
Torres, JB & JR Ruberson. 2006. Spatial and temporal dynamics of oviposition behavior of bollworm and three of its predators in Bt and non-Bt cotton fields. Entomologia Experimentalis et Applicata 120: 11-22. PDF file
Torres, JB & JR Ruberson. 2006. Interactions of Bt-cotton and the omnivorous big-eyed bug Geocoris punctipes (Say), a key predator in cotton fields. Biological Control 39: 47-57. PDF file
Ruberson, JR & AE Knutson. 2006. Assessment of the impact of insecticides on arthropod natural enemies, pp. 100-103. In: JN All and MF Treacy (eds.), Utilization and Management of Insecticides, Acaricides, and Transgenic Crops. Entomological Society of America. Lanham, MD.
Developing methods for encouraging and conserving natural enemy populations.
This area is a practical integration of the others. Our lab seeks to develop methods for encouraging survival and activity of natural enemies in cropping systems. These studies incorporate our understanding of food and overwintering requirements of key natural enemies, and also underscore areas where additional data are needed. We are currently working with organic vegetable producers to develop border and floral plantings to enhance natural enemy food resources and overwintering habitat. Organic producers have limited pest management options, and their systems are more favorable for integration of biological control, making it a preferred tactic for insect pest management.
Selected Other Publications
Knutson, A & JR Ruberson. 1997. Field Guide to Predators, Parasites and Pathogens Attacking Insect and Mite Pests of Cotton. Texas Agric. Ext. Serv., College Station TX. 122 pp.
Ruberson, JR, JR Nechols & MJ Tauber. 1999. Biological control of arthropod pests, pp. 417-448. In: JR Ruberson (ed.), Handbook of Pest Management. Marcel Dekker, Inc., New York.
Ruberson, JR & L. Williams. 2000. Biological control of Lygus spp.: A component of areawide management. Southwest. Entomol., Suppl. 23: 96-110.
Seagraves, MP, RM McPherson & JR Ruberson. 2004. Impact of Solenopsis invicta Buren suppression on arthropod ground predators and pest species in soybean. J. Entomol. Sci. 39: 433-443.
Head, G, W Moar, M Eubanks, B Freeman, J Ruberson, A Hagerty & S Turnipseed. 2005. A multiyear, large-scale comparison of arthropod populations on commercially managed Bt cotton and non-Bt cotton fields. Environ. Entomol. 34: 1257-1266. PDF file