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David G Riley

  • Entomology
Mailing Address:
Tifton, CAES Campus

Research and Outreach

The Vegetable Entomology Research Lab at Tifton has responsibilities for solving the most critical vegetable insect pest problems facing Georgia growers. Georgia produces $0.8-$0.9 billion farm gate value in vegetables each year. In 2009-2011, the top $ ranked vegetable commodities were: 1) Onions, 2) Watermelon, 3) Bell Pepper, 4) Sweet Corn, 5) Tomato, 6) Cucumber, 7) Greens, 8) Cabbage, 9) Snap Beans, 10) Cantaloupe, 11) Yellow Squash, 12) Eggplant, 13) Zucchini, 14) Southern Peas, and 15) Hot or Banana Peppers. In recent years, whiteflies, fruit and foliage feeding lepidopteran larvae, stinkbugs and beetles have risen to the top as important vegetable pest groups. Thrips and thrips-vectored viruses have decreased in importance since 2005-2007 since an effective management program has been developed through this laboratory (see and for more information). The specific kinds of investigation conducted in this laboratory over the last 10 years have included plant-insect interaction, sampling, population dynamics, economic thresholds, host plant resistance, cultural controls, insecticide efficacy and resistance monitoring, and epidemiology associated with insect vectors of plant virus. A recent research project has focused on the management of whitefly, Bemisia tabaci B-strain, as a vector of tomato yellow leaf curl virus (TYLCV) in solanaceous and other vegetable crops. Another problem of particular importance being addressed is insecticide resistance in the diamondback moth, Plutella xylostella. This insect has caused severe problems for cabbage and collard greens growers in Georgia when insecticides failed due to resistance. It is one of the first vegetable pests that exhibits selection for resistance against new insecticides. Other vegetable insects that are researched in the Vegetable Entomology Lab include various thrips species, cowpea curculio, pepper weevil, diamondback moth, cabbage looper, imported cabbageworm, squash bug, horned squash bug, melon aphid, corn earworm, fall armyworm, pickleworm, leaffooted bugs, cucumber beetles and others. Some IPM information on vegetable pests and individual pest fact sheets are being posted , but this is an on-going process.

Cowpea curculio adult and larval damage to peas.Cowpea curculio adult and larval damage to peas.
Vegetable Entomology Lab 2013 at the Tifton CampusVegetable Entomology Lab 2013 at the Tifton Campus


Currently (2013), one MS graduate student in the Vegetable Entomology Lab is investigating whitefly management that could lead to a reduction in TYLCV transmission in vegetable crops. A second MPPPM student will be beginning a brand new project investigating the management of cowpea curculio, Chalcodermus aeneus, in southern peas. This lab continues to offer the course, ENTO 4350 Crop-Specific Insect Management. Other courses that have been or will be supported at the Tifton Campus are ENTO 3900 Special Problems in Entomology and ENTO 4000/6000 General Entomology.

Selected Refereed Journal Articles

Riley, D. 2013. Insecticide rotations for the management of lepidopteran pests in cabbage and collards. J. Entomological Science (in press)

Shrestha, A., R. Srinivasan, S. Sundaraj, A. Culbreath, and D. Riley. 2013. Second generation peanut genotypes resistant to thrips-transmitted Tomato spotted wilt virus exhibit tolerance rather than true resistance and differentially affect thrips fitness. J. Econ. Entomol. 106: 587-596.

Srinivasan, R., S. Sundaraj, H. Pappu, S. Diffie, D. Riley, and R. Gitaitis. 2012. Transmission of Iris yellow spot virus by Frankliniella fusca and Thrips tabaci (Thysanoptera: Thripidae).  J. Econ. Entomol. 105: 40-47

Riley, D
., S. Joseph, C. Gunter, and D. Langston.  2012.   Host plant resistance to thrips-transmitted Tomato spotted wilt virus (Bunyaviridae: Tospovirus) in pepper in Georgia and North Carolina, Subtropical Plant Science Journal 64: 1-12.

Srinivasan, R., D. Riley, S. Diffie, A. Sparks, and S. Adkins. 2012. Whitefly population dynamics and evaluation of whitefly-transmitted Tomato yellow leaf curl virus (TYLCV)-resistant tomato genotypes as whitefly and TYLCV reservoirs.  J. Econ. Entomol. 105(4): 1447-1456 DOI:

Shrestha, A., R. Srinivasan, D.G. Riley and A.K. Culbreath. 2012. Direct and indirect effects of a thrips-transmitted Tospovirus on the preference and fitness of its vector, Frankliniella fusca. Entomologia Experimentalis et Applicata 145: 260–271.

Awondo, S.N., E. G. Fonsah, D. Riley and M Abney. 2012. Stated effectiveness of Tomato-spotted wilt virus management tactics, Journal of Economic Entomology, June issue, 105(3): 943–948.

Riley, D.G.
, S. V. Joseph, R. Srinivasan. 2011. Temporal relationship of thrips populations to Tomato spotted wilt incidence in tomato in the field. J. Entomological Science 47: 65-75.

Riley, D.G.
, S. V. Joseph, R. Srinivasan. 2011. Reflective Mulch and Acibenzolar-S-methyl treatments relative to thrips (Thysanoptera: Thripidae) and Tomato spotted wilt virus incidence in tomato.  J. Econ. Entomol. 105: 1302-1310.

Riley, D. G.
, S. V. Joseph, R. Srinivasan, and S. Diffie. 2011. Thrips vectors of tospoviruses. J. Integ. Pest Mngmt. 1(2): 2011, DOI: 10.1603/IPM10020.

Ni, X., A. N. Sparks, Jr., D. G. Riley, and X. Li. 2011. Impact of edible oils on ear pests of sweet corn. J. Econ. Entomol. 104: 956-964 (doi: 10.1603/EC10356).

Srinivasan, R., and F. Guo, D. Riley, S. Diffie, R. Gitaitis, A. Sparks, and A. Jeyaprakash. 2011. Assessment of variation among Thrips tabaci populations from Georgia and Peru based on polymorphism in mitochondrial cytochrome oxidase I and ribosomal ITS2 sequences. J. Entomol. Sci. 46(3): 191-203.

Sundaraj, S., R. Srinivasan, C. Webster, S. Adkins, K. Perry, and D. Riley. 2011. First report of Tomato chlorosis virus in Georgia. Plant Dis. 95:881.

Srinivasan, R., S. Diffie, S. Sundaraj, S. Mullis, D. Riley, R. Gitaitis, and H. Pappu. 2011. Evaluation of lisianthus (Eustoma grandiflorum) as an Indicator host for Iris yellow spot virus. Plant Dis. 95(12): 1520-1527. 

Riley, D. G.
, S. V. Joseph, W. T. Kelley, S. Olson, and J. Scott. 2011. Host plant resistance to Tomato spotted wilt virus (Bunyaviridae: Tospovirus) in tomato. HortScience. 46(12):1626–1633.

Sparks, A.N., S. Diffie, D.G. Riley. 2010. Thrips species composition on onions in the Vidalia production region of Georgia. J. Entomol. Sci. 46:1-6.

Riley, D. G.
, G. M. Angelella, and R. M. McPherson. 2010. Pine pollen dehiscence relative to thrips (Thysanoptera: Thripidae) population dynamics. Entomologia Experimentalis et Applicata DOI:10.111/j1570-7458.2011.010995.

Erickson, M.C., J. Liao, A. Payton, D. Riley, C. Webb, L. Davey, S. Kimbrel, L. Ma, G. Zhang, M.P. Doyle, and L.R. Beuchat. 2010. Pre-harvest Internalization of E. coli O157:H7 into lettuce leaves as impacted by the presence of insects. J. Food Protection 73(10):1809–1816.

Angelella, G. and D. G. Riley. 2010. Life table bioassay for pine pollen effects on Frankliniella fusca reproduction on onion. Environ. Entomol. 39(2): 505-512.

Joost, H. and D. G. Riley. 2008. Tomato plant and leaf age effects on the probing and settling behavior of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera:Thripidae). Environ. Entomol. 37:213-223.

Taylor, J. E. and D. G. Riley. 2007. Artificial infestations of beet armyworm, Spodoptera exigua, in tomato to estimate an economic injury level. Crop Protection Crop Protection, 27 (2), p.268-274.

Joost, H. and D. G. Riley. 2007. Tomato plant and leaf age effects on the probing and settling behavior of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera:Thripidae). Environ. Entomol. 37:213-223.

Riley, D. G.
, A. Chitturi, and A. N. Sparks, Jr. 2007. Does natural deposition of pine pollen affect the ovipositional behavior of Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae)? Entomol. Exp. et Appl. 124: 133–141.

Taylor, J. E. and D. G. Riley. 2007. The use of metaflumizone against beet armyworm, Spodoptera exigua, to estimate an action threshold in tomato. J. Entomol. Sci. 42: 430-434.

Riley, D. G.
2007. Distribution of grasshoppers and katydids (Orthoptera: Acrididae and Tettigoniidae in leafy greens prior to mechanical harvest. J. Entomol. Sci. 42(2): 261-271.

Riley, D. G.
2007. Effect of imidacloprid on the settling behavior of Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae) on tomato and peanut. J. Entomol. Sci. 42:74-83.

Chitturi, A., D. G. Riley, and P. H. Joost. 2006. Effect of pine pollen on settling behavior of Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae) in tomato in peanut. Environ. Entomol. 35:1396-1403.

Kuhar, T. P., W. D. Hutchinson, J. Whalen, D. G. Riley, J. C. Meneley, H. B. Doughty, E. C. Burkness, and S. J. Wold-Burkness. 2006. Field evaluation of a novel lure for trapping seedcorn maggot adults. Plant Health Progress doi:10.1094/PHP-2006-0606-01-BR.

McPherson, R. M. and D. G. Riley. 2006. Monitoring thrips (Thysanoptera: Thripidae) presence in flue-curred tobacco using yellow sticky traps. J. Entomol. Sci. 41:170-178.

Chaisuekul, C. and D. G. Riley. 2005. Host Plant, Temperature, and Photoperiod Effects on Ovipositional Preference of Frankliniella occidentalis and F. fusca (Thysanoptera: Thripidae). J. Econ. Entomol. 98: 2107-2113.

Joost, H. and D. G. Riley. 2005. Imidacloprid differentially effects probing and settling behavior of Frankliniella fusca (Hinds) and Frankliniella occidentalis (Pergrande) (Thysanoptera: Thripidae). J. Econ. Entomol. 98: 1622-1629.

Mullis, S. W., D. B. Langston Jr., R. D. Gitaitis, J. L. Sherwood, and A. C. Csinos, D. G. Riley,
A. N. Sparks, R. L. Torrance, and M. J. Cook IV. 2004. First Report of Vidalia onion (Allium cepa L.) in Georgia Naturally Infected with Tomato spotted wilt virus and Iris yellow spot virus (family Bunyaviridae, genus Tospovirus). Plant Dis. 88:1285.

Riley, D.
and Weijia Tan. 2004. Reproductive vigor in Bemisia agentifolii (Homoptera: Aleyrodidae) associated with bifenthrin resistance. J. Entomol. Sci. 39:567-578.

Riley, D.
and H. Pappu. 2004. Tactics for Management of Thrips (Thysanoptera: Thripidae) and Tomato Spotted Wilt Tospovirus in Tomato. J. Econ. Entomol 97:1648-1658.

Joost, P.H. and D. G. Riley. 2004. Sampling techniques for thrips (Thysanoptera: Thripidae) in pre-flowering tomato. J. Econ. Entomol. 97: 1450-1454.

Riley, D. G.
, and W. Tan. 2003. Host plant effects on resistance to bifenthrin in silverleaf whitefly (Homoptera: Aleyrodidae). J. Econ. Entomol. 96: 1315-1321.

Riley, D. G.
, and W. Tan. 2002. Increased vigor in whitefly (Homoptera: Aleyrodidae) associated with bifenthrin-resistant males. J. Entomol. Sci. 37: 77-82.

Chaisuekul, C. and D. G. Riley. 2001. Thrips (Thysanoptera: Thripidae) feeding response to concentrations of imidacloprid in tomato leaf tissue. J. Entomol. Sci. 36: 315-317.

Nava-Camberos, U., D. G. Riley, and M. K. Harris. 2001. Temperature and host plant effects on development, survival, and fecundity of Bemisia argentifolii (Homoptera: Aleyrodidae). Environ. Entomol. 30: 55-63.

Nava-Camberos, U., D. G. Riley, and M. K. Harris. 2001. Density-yield relationships and economic injury levels of Bemisia argentifolii (Homoptera: Aleyrodidae) in Cantaloupe. J. Econ. Entomol. 94: 180-189.

Riley, D.
, D. Batal, and D. Wolff. 2001. Resistance in Glabrous-type Cucumis melo L. to Whiteflies (Homoptera: Aleyrodidae). J. Entomol. Sci. 36:46-56.

Riley, D. G.
, W. Tan, and D. A. Wolfenbarger. 2000. Activity of enzymes associated with inheritance of bifenthrin resistance in the silverleaf whitefly, Bemisia argentifolii. Southwestern Entomol. 25: 201-211.

Riley, D. G.
and H Pappu. 2000. Evaluation of tactics for management of thrips - vectored tomato spotted wilt Tospovirus in tomato. Plant Dis. 84:847-852.

Riley, D. G.
, W. Tan, and D. A. Wolfenbarger. 1999. Characterization of esterase isozymes from bifenthrin susceptible, resistant and crossed strains of the silverleaf whitefly (Homoptera: Aleyrodidae). J. Entomol. Science. 34: 295-304.

Naranjo, S. E., C. C. Chu, P. C. Ellsworth, T. J. Henneberry, R. L. Nichols, D. G. Riley, and T. F. Watson. 1998. Action thresholds for the management of Bemisia tabaci (Homoptera: Aleyrodidae) in cotton. J. Econ. Entomol. 91:1415-1426.

Loera-Gallardo, J., D. A. Wolfenbarger, and D. G. Riley. 1998. Insecticidal mixture interactions against B-strain sweetpotato whitefly (Homoptera: Aleyrodidae). J. Entomol. Science 33(4): 407-411.

Wolfenbarger, D. A., D. G. Riley, G.L. Leibee, E.V. Gage, C.A. Staetz, G.A. Herzog. 1998. Response of b-strain sweetpotato whitefly to bifenthrin and endosulfan by vial bioassay in the southern United States. J. Entomol. Science 33(4):412-420.

Riley, D. G.
, and M. A. Ciomperlik. 1997. Whitefly (Homoptera: Aleyrodidae) and associated arasitoid (Hymenoptera: Aphelinidae) population dynamics in the lower Rio Grande Valley of Texas. Environ. Entomol. 26: 1049-1055.

Tan, W., D. G. Riley, and D. A. Wolfenbarger. 1996. Quantification and genetic analysis of bifenthrin resistance in silverleaf whitefly Bemisia argentifolii. Southwest. Entomologist 21:265-27.

Riley, D. G.
1995. Melon cultivar response to Bemisia. Subtropical Plant Science. 47:39-45.

Riley, D. G.
and J. C. Palumbo. 1995. Action thresholds for Bemisia argentifolii (Homoptera: Alerodidae) in cantaloupe. J. Econ. Entomol. 88:1733-1738.

Riley, D. G.
and J. C. Palumbo. 1995. Interaction of silverleaf whitefly (Homoptera: Alerodidae) with cantaloupe yield. J. Econ. Entomol. 88:1726-1732.

Ahmed, K., F. Khalique, B. A. Malik and D. Riley. 1994. Use of microbial insecticides in Pakistan: special reference to control of chickpea pod borer, Helicoverpa armigera (Hubner). Subtropical Plant Science 46:38-44.

Riley, D. G.
1994. Insecticide control of sweetpotato whitefly in south Texas. Subtropical Plant Science. 46: 45-49.

Riley, D. G.
and E. King. 1994. Biology and management of the pepper weevil: a review. Trends in Agricultural Science. 1994(2): 109-121.

Riley, D. G.
1993. A new occurrence of broad mites in peppers in the Lower Rio Grande Valley of Texas. Subtropical Plant Science 45: 46-48.

Eller, F. J., R. J. Bartelt, B. S. Shasha, D. J. Schuster D. G. Riley, P. A. Stansly, T. F. Mueller, K. Schuler, B. Johnson, J. H. Davis and C. A. Sutherland. 1993. Aggregation pheromone for the pepper weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae): identification and field activity. J. Chem. Ecol. 20(7): 1537-1555.

Riley, D. G.
and D. J. Schuster. 1993. Pepper weevil (Coleoptera: Curculionidae) adult response to colored sticky traps in pepper fields. Southwestern Entomologist. 19(2): 93-107.

Berdegue, M., M. Harris, D. Riley, B. Villalon. 1993. Host plant resistance on pepper to pepper weevil (Anthonomus eugenii Cano). Southwestern Entomologist. 19 (3): 265-271.

Riley, D. G.
and D. J. Schuster. 1992. The occurrence of Catolaccus hunteri, a parasitoid of Anthonomus eugenii, in insecticide treated pepper. Southwestern Entomologist 17(1): 71-72.

Riley, D. G.
, D. J. Schuster, and C. S. Barfield. 1992. A refined action threshold for pepper weevil adults, Anthonomus eugenii Cano (Coleoptera: Curculionidae), in bell peppers. J. Econ. Entomol. 85: 1919-1925.

Riley, D. G.
, D. J. Schuster and C. S. Barfield. 1992. Sampling and dispersion of pepper weevil adults, Anthonomus eugenii Cano (Coleoptera: Curculionidae). Environ. Entomol. 21: 1013-1021.

Riley, D. G.
, G. J. House and J. Van Duyn. 1987. Effect of phorate on soil arthropods and soybean productivity in a North Carolina coastal plain cropping system. J. Entomol. Sci. 22(4): 317-323.