Progress 04/01/99 to 03/31/04
Outputs
Vegetable production is a growing industry in Georgia. The growth of this industry has been in part because of the utilization of plasticulture and drip irrigation systems. As part of this project we have conducted various studies intended to improve the yield, quality, and production efficiency of Georgia vegetables. Our results have provided information on the effects of plastic film mulches on plant growth, fruit yield, and plant responses to attack of plant viruses (Tomato spotted wilt) in tomato and bell pepper. One result of particular importance for tomato and other vegetable growers in the southeast U.S. is that high-temperature conditions during the summer can be deleterious to plant growth and yield under certain types of plastic film mulches. Thus, proper plastic film mulch selection must consider the soil-warming ability of mulches, in addition to the planting season, geographical location, and crop climatic requirements.
Impacts
The utilization of plastic film mulches has significantly contributed to the increasing vegetable production in Georgia. Our research on crops grown on plastic film mulches has provided information to better understand the plant-root zone temperature interaction and how this interaction may affect plant growth, fruit yield, and the response of the plants to biotic factors such as viral diseases. This information is expected to be useful to growers, allowing them to better select the type of plastic film mulch to use. The information is also expected to be useful to the various industries (pigments, additives, master batch producers, etc.) involved in the manufacturing of plastic film mulch.
Publications
- Gitaitis, R.D., R.R. Walcott, H.F. Sanders, L. Zolobowska, and J.C. Diaz-Perez. 2004. Effects of mulch and irrigation system on sweet onion: II. The epidemiology of center rot. J. Amer. Soc. Hort. Sci. 129:225-230.
- Martini, N.L, H.H. Schomberg, S.C. Phatak, and J.C. Diaz-Perez. 2004. Biomass accumulation of 'GA Bush' velvetbean on the Piedmont and Coastal Plain of Georgia. In: D.L. Jordan and D.F. Caldwell (eds.). Proc. 26th Southern Conservation Tillage Conf. for Sustainable Agriculture pp:67-75. North Carolina Agr. Res. Serv. Tech. Bul. No. TB-321 (http://www.ag.auburn.edu/nsdl/sctcsa).
- Seebold, K.W., F.S. Sanders, J.C. Diaz-Perez, and R.D. Gitaitis. 2004. Effect of solarization on soilborne pathogens and weeds in short-day, sweet onions in Georgia. 2004 Natl. Allium Res. Conf., Grand Junction, Col., 9-10 Dec.
- Diaz Perez, J.C., D. Giddings, and D. Bertrand. 2004. Plant growth and fruit yield of drip-irrigated bell pepper as affected by irrigation levels. Proc. 2004 Ga. Veg. Conf. p.117.
- Diaz-Perez, J.C. 2004. Acolchados plasticos de colores en jitomate y chile dulce: Efecto en el rendimiento y control del virus de la marchitez manchada (Effect of colored plastic film mulches on tomato yield and control of tomato spotted wilt). Tercer Simposium de Tecnologias Agricolas con Plastico (Abstracts of Third Symposium of Agricultural Technologies with Plastic), Amipac, Puebla, Mexico, 24-27 Feb.
- Diaz-Perez, J.C., W.M. Randle, G.B. Ronald, W. Walcott, D. Giddings, D. Bertrand, H.F. Sanders, and R.D. Gitaitis. 2004. Effects of mulch and irrigation system on sweet onion: I. Bolting, plant growth, and bulb yield and quality. J. Amer. Soc. Hort. Sci. 129:218-224.
- Diaz-Perez, J.C., D. Giddings, and D. Bertrand. 2004. Irrigation levels affect plant growth and fruit yield of drip-irrigated bell pepper. HortScience 39:748.
- Diaz-Perez, J.C., D. Granberry, D. Bertrand, and D. Giddings. 2004. Tomato plant growth during establishment as affected by root zone temperature under colored mulches. Acta Hort. 631:119-124.
- Diaz-Perez, J.C., D. Giddings, D. Bertrand, and R. Gitaitis. 2004. Growth analysis of sweet onion plants grown on organic and inorganic mulches. HortScience 39:658.
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Progress 01/01/03 to 12/31/03
Outputs
Tomato spotted wilt (TSW) is a viral disease that causes serious yield losses in tomato, bell pepper, peanut, tobacco, among other crops. This disease is transmitted by thrips and is difficult to control. Our results show that the incidence of the disease can be reduced by the use of resistant cultivars and the utilization of plastic film mulches. Results also show that tomato plant growth and yield are less affected by TSW the longer the plants remain free from symptoms of the disease. The use of TSW-resistant cultivars ('BHN-444') and utilization of silver mulches may be helpful in the management of TSW.
Impacts
Cultural management strategies such as the use of resistant cultivars and the utilization of silver mulches are important to delay the appearance of symptoms of TSW. Fruit yield and quality are less affected by TSW in those plants showing delayed TSW symptoms.
Publications
- Boyhan, G., Diaz-Perez, J.C., Culpepper, S., Torrance, R., Hardison, G. and Hill, R. 2003. Evaluation of various parameters for direct seeding of Vidalia onions. Georgia Onion 2003 Research-Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:19-23.
- Diaz Perez, J.C. 2003. Plastic film mulches as a means to modify root zone temperature and delay the appearance of Tomato spotted wilt virus in tomato. Proc. Natl. Agr. Plastics Cong. 31:119 123.
- Diaz-Perez, J.C. and Gitaitis, R.D. 2003. Yield of sweet onion as affected by irrigation system and mulch. Georgia Onion 2003 Research-Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:24-27.
- Diaz-Perez, J.C., Batal, K.D., Granberry, D., Bertrand, D., Giddings, D. and Pappu, H. 2003. Vegetative top growth and yield of tomato grown on plastic film mulches as affected by the appearance of symptoms of Tomato spotted wilt virus. HortScience 38:395-399.
- Diaz-Perez, J.C., Bertrand, D. and Giddings, D. 2003. Yield responses of tomatillo (Physallis ixocarpa Brot.) grown on colored plastic film mulches in Georgia. Georgia Onion 2003 Research-Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:18-19.
- Diaz Perez, J.C., Granberry, D., Giddings, D. and Bertrand, D. 2003. Do we understand how plastic mulches work? Effect of soil-warming ability of plastic mulches on tomato plant growth and fruit yield. Proc. 2003 Ga. Veg. Conf. pp. 97-100.
- Diaz-Perez, J.C., Purvis, A. and Paulk, J. T. 2003. Bolting, yield and bulb decay of sweet onion as affected by nitrogen fertilization. J. Amer. Soc. Hort. Sci. 128: 144-149.
- Diaz-Perez, J.C., Purvis, A.C. and Paulk, J.T. 2003. Nitrogen fertilization affects bolting and yield of sweet onion. HortScience 38:1287.
- Gitaitis, R.D., Walcott, R.R., Diaz-Perez, J.C., Wells, M.L. and Sanders, F.H.. 2003. Transmission of Pantoea ananatis, causal agent of center rot of onion, by tobacco thrips, Frankliniella fusca. Plant Dis. 87:675-678.
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Progress 01/01/02 to 12/31/02
Outputs
Sweet (Vidalia-type) onions are typically grown on bare soil and are irrigated with high-pressure systems such as sprinklers or center-pivots. These irrigation methods are often inefficient as to water use. Preliminary data show that onions require about 325,000 gal of irrigation water per acre during the growing season. There is presently no information on the utilization of drip irrigation and plastic mulch for onion production in Georgia. The results of a three-year study showed that bulb yields and quality under drip irrigation were at least similar to those under sprinkler irrigation. Plants grown on bare soil had the highest total yield during the three seasons and among the highest marketable yield. There were no consistent differences in the bulb number or yield of plants on plastic film mulch compared to those of plants under wheat straw mulch. Plants on wheat straw mulch had reduced foliage nitrogen content. Variability in yields among mulches and seasons
was partly explained by changes in seasonal root zone temperature and soil moisture (soil water potential). Total and marketable yields and weight of individual bulbs increased with increasing root zone temperatures up to an optimum at 15.8 C, followed by reductions in yields and individual bulb weight at root zone temperature higher than 15.8 C. Onion bolting increased with decreasing foliage nitrogen content, with plants on wheat straw having the highest bolting incidence. Bolting also increased with decreasing root zone temperatures for the season. Total and marketable yields increased with decreasing mean seasonal soil water potential down to -30 kPa. Irrigation system and mulches had no consistent effect on the soluble solids content or pungency of onion bulbs.
Impacts
`Vidalia' onions are produced on about 14,000 acres in Georgia, with a value in excess of $75 million. Our results show that plants under drip irrigation can be grown with 20% less irrigation water compared to plants grown under overhead sprinklers. Thus, onion production under drip irrigation may result in water savings of about 608 cubic meter per ha (65,000 gal per acre) compared to onion plants grown under sprinkler irrigation. These water savings represent about 3.4 million cubic meters (0.9 billion gallons) for the total onion acreage in Georgia.
Publications
- Gitaitis, R.D., F. Sanders, R. Torrance, D. Langston, J.C. Diaz-Perez, R.R. Walcott. 2002. Review of management of the diseases bacterial streak and center rot of onion. 2000 Georgia Onion Research and Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:39-45.
- Walcott, R.R., R. D. Gitaitis, A. C. Castro, F. H. Sanders Jr., and J.C. Diaz-Perez. 2002. Natural infestation of onion seed by Pantoea ananatis, causal agent of center rot. Plant Disease 86 (2): 106-111.
- Boyhan, G., J.C. Diaz-Perez, R. Torrance, D. Curry, G. Hardsion, J. Cook, R. Hill. 2002. Direct seeding Vidalia onions. 2002 Georgia Onion Research and Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:11-14.
- Diaz-Perez, J.C. 2002. Appearance of symptoms of Tomato Spotted Wilt Virus in tomato as affected by colored plastic film mulches. Proc. 2002 Ga. Veg. Conf. pp. 39-40.
- Diaz-Perez, J.C. and K. M. Batal. 2002. Colored mulches affect tomato growth and yield via changes in root zone temperature. J. Amer. Sci. Hort. Sci. 127:127-136.
- Diaz-Perez, J.C., A. Purvis, T Paulk. 2002. Nitrogen fertilization affects bolting and decay of sweet onions. 2002 Georgia Onion Research and Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:30-32.
- Diaz-Perez, J.C., D. Bertrand, D. Giddings, H. Sanders, R. Walcott, R. Gitaitis. 2002. Mulches affect bolting and yield in sweet onions. 2002 Georgia Onion Research and Extension Report, The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus, pp:33-38.
- Diaz-Perez, J.C., D. Granberry, B. Mandal, D. Bertrand, and D. Giddings. 2002. Plant growth and yield of tomato grown on colored mulches as affected by the time of appearance of symptoms of Tomato Spotted Wilt Virus. Proc. Intl. Cong. Plast. Agric. 16:149-154.
- Diaz-Perez, J.C., D. Granberry, B. Mandal, D. Bertrand, and D. Giddings. 2002. Effects of Tomato spotted wilt virus on plant growth, yield and fruit quality of drip-irrigated tomato plants. Georgia Vegetable Extension-Research Report, Univ. of Ga., College Agric. Env. Sci. UGA/CPES Research-Extension Pub. No. 5-2001, pp:125-128.
- Diaz-Perez, J.C., D. Granberry, D. Bertrand, and D. Giddings. 2002. Tomato transplant growth as affected by root-zone temperature under colored plastic mulches. XXVIth International Hort. Cong. of the Int. Soc. Hort. Sci. pp. 554.
- Diaz-Perez, J.C., D. Granberry, D. Giddings, and D. Bertrand. 2002. Bell pepper yield and blossom-end rot as affected by calcium application and irrigation rates. Proc. 2002 Ga. Veg. Conf. pp. 64-65.
- Diaz-Perez, J.C., R. Gitaitis, D. Bertrand, D. Giddings, W. Randle. 2002. Influence of mulches and drip irrigation on the growth, yield and quality of Vidalia onion. HortScience 37(5):748.
- Diaz-Perez, J.C., R. Gitaitis, W. Randle, K. Harrison, and R. Torrence. Influence of mulches and drip irrigation on the growth and yield of Vidalia onion. Proc. 2002 Ga. Veg. Conf. pp. 8-9.
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Progress 01/01/01 to 12/31/01
Outputs
Tomato is an important vegetable in Georgia, with a farm gate value of over $33 million. The majority of tomato is grown on plastic film mulches. The use of plastic film mulches is based primarily on subjective descriptions of the mulch, such as a visual evaluation of mulch color. However, there is a great variability on how plants respond to plastic mulches. Soil warming is one of the benefits associated with use of plastic film mulches. However, under high temperature conditions as during the summer in Georgia, mulches warm the soil to temperatures that might be deleterious to plant growth. Our results showed that the effects of colored mulches on tomato growth and yield depended on the impact of the mulch on soil temperature. Yields of tomato plants grown on plastic mulches of apparently the same color differed as much as 50%. Tomato plant growth and yield were highest as soil temperature (mean for the season) approached the optimal for tomato plants (26 C). The
variability in yields among mulches was due, at least partially, to the differences in soil-warming ability of the mulches. The results from our studies will help growers to choose the most appropriate mulch. The results suggest that mulch manufacturers should control and specify the optical and thermal properties of the mulches they produce. Tomato spotted wilt disease (TSWV) causes serious damage to tomato in Georgia. Annual losses due to TSWV in tomato, pepper, peanut and tobacco exceed $100 million in Georgia alone. Insecticides are often ineffective to control the vector (thrips) of this disease. We determined that the weight of plant's top and fruit yields were reduced about 2%, for each day prior to harvesting the plant showed TSWV symptoms. Our results also indicated that silver mulches were effective in delaying the appearance of TSWV symptoms. Thus, colored plastic mulches may be useful in the management of TSWV.
Impacts
The results from this project have increased our understanding of the effect of colored mulches on plant growth, yield and response to tomato spotted wilt disease. This information is expected to result in a more effective use of colored mulches that would translate into higher yields. We found that tomato yields are related with the time (days before harvest) when first symptoms of tomato spotted wilt (TSWV) appear and that colored mulches may delay the appearance of TSWV symptoms. These findings will be useful in the management of TSWV.
Publications
- Gitaitis, R.D., J.C. Diaz-Perez, F.H. Sanders, R.R. Walcott. 2001. Center rot of onion, caused by the bacterium Pantoea ananatis: Effects of mulch and irrigation. 2000 Georgia Onion Research and Extension Report, The University of Georgia, CAES, pp:28-31.
- Granberry, D.M., W. T. Kelley, D.B. Langston, J.C. Diaz-Perez, and K.S. Rucker. 2001. The effects of on-farm-produced compost on transplant and field production of bell pepper. HortScience 36:844.
- Granberry, D.M., W. T. Kelley, D.B. Langston, K.S. Rucker, and J.C. Diaz-Perez. 2001. Testing compost value on pepper plants. BioCycle 42(10):60-62.
- Diaz-Perez, D. Batal, D. Bertrand, and D. Giddings. 2001. Tomato plant growth and yield as affected by root-zone temperature under colored mulches. HortScience 36:578.
- Diaz-Perez, J.C., R. Gitaitis, D. Batal, W. Randle, K Harrison, and R. Torrence. 2001. Response of sweet onion to the use of plastic mulch and drip irrigation. HortScience 36:845.
- Diaz-Perez, J.C., R.D. Gitaitis, W. M. Randle, K A. Harrison, and R.L. Torrence. 2001. Mulches and drip irrigation in onions: Effect on yield and bulb quality. 2000 Georgia Onion Research and Extension Report, The University of Georgia, CAES, pp:22-26.
- Muy Rangel, M..D. and J.C. Diaz-Perez. 2001. Efecto del tiempo de cosecha sobre algunas caracteristicas fisicas y fisiologicas del fruto de chile bell (Physical and chemical characteristics of bell pepper fruit as affected by harvest time). Proc. 47th Meeting Interamer. Soc. Trop. Hort. pp: 312.
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Progress 01/01/00 to 12/31/00
Outputs
Colored Mulches: Soil warming is one of the benefits associated with the use of plastic mulches in vegetable crop production. However, this increased soil temperature may be deleterious to plant growth under high temperature conditions in the field, which occurs during the summer in south Georgia. Our results indicate that soil temperature, as affected by colored plastic mulches, was related to tomato plant growth and yield of three tomato cultivars. Plant growth and yield were highest as soil temperature under the mulch (root zone temperature) approached the optimum temperature for tomato roots. Our results suggest that the responses of tomato plants under colored mulches are highly dependent on the root thermal environment. These results are expected to contribute to our understanding of plant responses under plastic mulches. Onion Drip Irrigation: In Georgia, Vidalia onions are produced on over 15,000 acres with a value in excess of $75 million. Onions are
typically irrigated with high-pressure systems, such as, sprinklers or center-pivots. These irrigation methods often yield inefficient water usage. Preliminary data estimates that onions require about 325,000 gal. of water per acre during the growing season. Drip irrigation is usually more efficient in water use compared to high-pressure irrigation systems, particularly during early plant growth. Drip irrigation allows for the delivery of fertilizers and pesticides in the irrigation water, resulting in the placement of these chemicals close to the root zone, thus increasing the efficiency in the use of nutrients. Also, drip irrigation does not moisten the foliage of the crop, thus it may reduce the incidence and spread of foliar diseases. Georgia has been experiencing drought conditions in the last few years. This water deficiency has resulted in the need to find ways to conserve and optimize water resources. Drip irrigation is expected to increase the efficiency in the use of
irrigation water for onion production. A research project was started in the 1999-2000 season with the objective of increasing the efficiency of water use in sweet onion through the utilization of drip irrigation. However, any change in irrigation systens must guarantee that the quality of the Vidalia onion is maintained. Thus, the project also focuses on determining the influence of drip irrigation on onion bulb quality and incidence of onion diseases.
Impacts
Colored mulches affected tomato plant growth and subsequent yield through their effect on soil temperature. The results from this project will help us better understand how tomatoes and peppers respond to specific plastic mulches. As an additional component of the project, we evaluated Vidalia onion production under drip irrigation and plastic mulch. The results from the first year of the project indicates that total yields of plants under drip irrigation were at least similar to those of plants irrigated with sprinklers. Plants under drip irrigation received 20% less irrigation water (i.e., 65,000 gal of water per acre) compared to plants irrigated with sprinklers.
Publications
- Diaz-Perez, J.C., Batal, D., Bertrand, D. and Giddings, D. 2000. Excessive soil warming affects tomato plants grown over colored mulches. Vegetable Research and Extension - Annual Report, CAES, University of Georgia (In press).
- Diaz-Perez, J.C., Batal, D., Bertrand, D. and Giddings, D. 2000. Effects of tomato spotted leaf virus on plant growth, yield and fruit quality of drip-irrigated tomato plants. Vegetable Research and Extension - Annual Report, CAES, University of Georgia (In press).
- Diaz-Perez, J.C., Batal, D., Bertrand, D. and Giddings, D. 2000. Colored plastic mulches affect tomato plant growth and yield via changes in soil temperature. Proc. Intl. Cong. Plast. Agric. 15:544-552.
- Gitaitis, R.D., Diaz-Perez, J.C., Culpepper, S., Purvis, A.C., Walcott, R.R., Langston, D.B. and Riley, D.G. 2000. Bacteriology Report. 1999 Georgia Onion Research-Extension Report. The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus. pp. 9-17.
- Pappu, S.S., Pappu, H.R. Langston, D.B. Jr., Flanders, J.T., Riley, D.G. and Diaz-Perez, J.C. 2000. Outbreak of tomato yellow leaf curl virus (Family Geminiviridae) in Georgia. Plant Disease 84:370.
- Diaz-Perez, J.C. and Pappu, H.R. 2000. First report of tomato spotted wilt virus infection of tomatillo in Georgia. Plant Disease 84(10):1155.
- Diaz-Perez, J.C., Batal, D., Bertrand, D., and Giddings, D. 2000. Tomato plant size and fruit yield as affected by symptom appearance of tomato spotted leaf virus. HortScience 35:392.
- Diaz-Perez, J.C. and Gitaitis, R.D. 2000. Sweet onion production with drip irrigation and soil mulches: Effects on incidence of bacterial diseases, yield and bulb quality. 1999 Georgia Onion Research-Extension Report. The University of Georgia, College of Agricultural and Environmental Sciences, Tifton Campus. pp. 8.
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Progress 01/01/99 to 12/31/99
Outputs
Soil warming is one of the benefits associated with the use of plastic mulches in vegetable crop production. However, this increased soil temperature may be deleterious to plant growth under high temperature conditions in the field, which occurs during the summer in Southern Georgia. In 1999 experiments, plant growth and yield differed among various colored mulches (white, gray, silver reflective, and black). During the first 30 days after transplanting, stem diameter and plant leaf area decreased linearly with increases in soil temperature. During the same period, relative growth rate (RGR) was also a function of soil temperature. The maximum RGR occurred when the mean soil temperature (10-cm depth) was about 30 C. Values of RGR decreased as mean soil temperature increased above 30 C, approaching zero when mean soil temperature was higher than 32 C. In mature plants, as soil temperature increased there was also a linear reduction in the final plant weight, number of
fruit per plant and total fruit weight per plant. Plants grown on silver mulch and bare soil were the heaviest, followed by plants on white mulch, black mulch painted white, and gray mulch. The number of fruits per plant was highest on plants grown on silver mulch and lowest on gray mulch. Thus, plant growth and fruit yield were directly correlated with soil temperature. The results of this research project are expected to contribute to our understanding of plant responses to plastic mulches under different environmental conditions. Compost applications (0 and 22 t/ha) in tomato resulted in increased plant size, number of fruit per plant and total fruit weight per plant, although there was no significant increase in marketable yield. The marketable yield was very low in both compost treatments because of a high incidence of white flies and tomato yellow leaf curl virus (TYLCV). Our findings represent one of the first reports of TYLCV in Georgia. The increased plant size and number of
fruit as a result of compost application suggests that compost was beneficial to tomato plants. Compost application may represent an option for vegetable crops grown under plasticulture conditions. We expect compost applications to result in improved physical and chemical characteristics of the soil, resulting in a more efficient utilization of nutrients and water by the plant. Compost may also contribute to the control of soil borne pathogens through its disease suppression properties.
Impacts
Colored mulches affected tomato plant growth and subsequent yield through their effect on soil temperature. The results from this project will help us better understand how tomatoes and peppers respond to specific plastic mulches. Compost applications may result in increased efficiency of water and nutrient uptake, and improved soil characteristics. Compost may also contribute to the management of soil borne diseases, through its disease suppression properties.
Publications
- No publications reported this period
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