2005 Georgia Plant Disease Loss Estimates (SB 41-08) University of Georgia Extension It is estimated that 2005 plant disease losses, including control costs, amounted to approximately $537.44 million. The value of the crops used in this estimate was approximately $4377.6 million, resulting in a 12.28 percent total disease loss across all crops included in this summary. 2017-03-23 11:55:45.83 2006-09-07 16:04:39.0 2005 Georgia Plant Disease Loss Estimates | Publications | UGA Extension Skip to content

2005 Georgia Plant Disease Loss Estimates (SB 41-08)

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Alfredo Martinez,
Extension Plant Pathologist

It is estimated that 2005 plant disease losses, including control costs, amounted to approximately $537.44 million. The value of the crops used in this estimate was approximately $4377.6 million, resulting in a 12.28 percent total disease loss across all crops included in this summary.

The estimated values for most crops used to compute these disease losses are summarized in Georgia Agricultural Statistics Service, Georgia Farm Report 6, No. 1 and the 2005 Georgia Farm Gate Value Report (AR-06-01). Estimates for tobacco are based on Market News Service figures for growers' net sales and do not include warehouse resales. Some estimates for grapes, ornamentals and turf rely on specialists' knowledge of the industry and industry sources for information.

The Following Members of the University of Georgia Department of Plant Pathology Made Direct Contribution to this Publication:
Paul Bertrand Tifton, Ga. 229-386-7495 bertrand@uga.edu
Phil Brannen Athens, Ga. 706-542-2685 pbrannen@uga.edu
Jason Brock Tifton, Ga. 229-386-7202 jbrock@uga.edu
Robert Kemerait Tifton, Ga. 229-386-7495 kemerait@uga.edu
David Langston Tifton, Ga. 229-386-7495 dlangsto@uga.edu
Alfredo Martinez Griffin, Ga. 770-228-7375 martinez@griffin.uga.edu
Jean Williams-Woodward Athens, Ga. 706-542-9140 jwoodwar@uga.edu
John Youmans Griffin, Ga. 770-412-4011 jyouman@griffin.uga.edu

2005 Plant Disease Clinic Annual Summary

Extension Plant Pathology maintains three clinics as educational resources for county extension agricultural faculty to use to aid their clients in diagnosing and correcting disease-related plant problems. Plant samples are submitted directly to the county extension faculty who, at their discretion, forward samples to the appropriate clinic. Commercial fruits, legume forage crops, forestry, Christmas tree, and commercial ornamental greenhouse, nursery and landscape samples are sent to the Plant Disease Clinic in Athens. Diagnoses of and control recommendations for commercial samples of field crops, grain forages, pecans and vegetables are handled by the Plant Disease Clinic at the Rural Development Center in Tifton, Georgia. Commercial turf and all non-commercial homeowner plant samples are sent to the Plant Disease and Homeowner IPM Clinics in Griffin for disease diagnoses and recommendations. Diagnoses and educational recommendations are returned to the county faculty. The clinics maintain a computerized database of samples and their diagnoses, as well as a reference library for use by extension agents, specialists, researchers and students.

Clinic Summaries: 2005 Plant Specimen Diagnosis
Crop Commercial Samples Homeowner IPM Clinic Total
Field Crops 259 8 267
Vegetables 265 58 323
Fruits & Nuts 93 64 157
Herbaceous Ornamentals 213 111 324
Woody Ornamentals 195 190 385
Trees 148 232 380
Turf 151 282 433
Miscellaneous 15 26 41
TOTAL 1339 971 2310

Apple

Apples had moderate to high disease pressures in 2005. This was due to exceptionally wet conditions from bloom throughout the entire season. Fire blight was prevalent if antibiotic sprays were not applied. As usual, bitter rot was a major issue; fungicides for bitter rot were not effective enough when wet conditions were observed, and rainy weather sometimes made fungicide application difficult. There is still a strong need for more efficacious fungicides for control of bitter rot and other summer rot diseases. In addition, though not yet observed, we are concerned that streptomycin antibiotic resistance may yet become an issue; currently, streptomycin is the only effective antibiotic for fire blight. if we lose this antibiotic due to resistance, apple production will be much more difficult. Cost of control included increased pesticide use for fire blight as well as increased pruning costs as a result of fire blight and summer rot control measures.

Disease % Reduction in Crop Value Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Fire Blight 5.0 184.9 70.0 254.9
Bitter Rot 5.0 184.9 100.0 284.9
Bot Rot 1.0 37.0 52.0 89.0
Black Rot 0.1 3.7 33.0 36.7
Alternaria Leaf Spot 0.1 3.7 0.0 3.7
Powdery Mildew 0.1 3.7 11.5 15.2
Sooty Blotch 0.1 3.7 0.0* 3.7
Fly Speck 0.1 3.7 0.0* 3.7
Cedar Apple Rust 0.1 3.7 0.0* 3.7
Scab 0.05 1.8 0.0* 1.8
Other Diseases 0.05 1.8 1.0 1.8
Total 11.7 432.6 267.5 699.1
*Controlled with fungicides applied for other diseases.
Estimated by Phil Brannen, Extension Plant Pathologist.

Blueberry

In 2005, disease losses were minimal despite heavy rainfall. Where spray programs were not applied effectively, mummy berry (both primary shoot blight and mummified fruit) was observed at very high levels, but this was rare. Likewise, Botrytis blight was prevalent when fungicides were not used during bloom. In southern highbush cultivars, problems due to foliar diseases and dieback were also observed, but the use of fungicides helped reduce these diseases. Rust was also prevalent on some varieties. Phytophthora root rot and other root rots were more prevalent as a direct result of excessive moisture.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Mummy Berry 0.2 65.2 250.0 315.2
Botrytis Blight 0.2 65.2 50.0 115.2
Foliar Disease 1.0 326.2 20.0 346.2
Dieback 1.0 326.2 10.0 336.2
Phytophthora Root Rot 0.1 32.6 5.0 37.6
Total 2.5 815.4 335.0 1,150.4
Estimate by Phil Brannen, Extension Plant Pathologist

Bunch Grape

Disease pressure was low to moderate among bunch grape vineyards in 2005 despite a very wet year with high disease potential. Disease control methods have obviously improved, largely as a result of educational efforts and grower adoption. Pathological issues, foliage diseases and rots resulted in minor losses in 2005. Where adequate spray programs were maintained, near 0 percent losses were observed in many cases. The degree of loss was directly correlated with the accuracy and intensity of the fungicidal spray program. When used correctly, fungicides and spray programs were very effective in disease control.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Botrytis 1.0 25.5 30.0 55.5
Downy Mildew 1.0 25.5 20.0 45.5
Black Rot 1.0 25.5 20.0 45.5
Powdery Mildew 1.0 25.5 5.0 30.5
Phomopsis Cane Blight 1.0 25.5 5.0 30.5
Crown Gall 0.1 2.6 5.0 7.6
Pierce's Disease 0.1 260 5.0 7.6
Total 5.2 132.7 90.0 222.7
Estimate by Phil Brannen, Extension Plant Pathologist

Corn

In 2005 corn was harvested from 274,284 acres in Georgia. The 2005 crop was valued at $84,483,442. Dry weather beginning in August likely reduced the total yield potential. Southern corn leaf blight was of minor importance in 2005. Southern rust, which was very important in 2003, was inconsequential in 2004 and in 2005. Rainfall was less abundant during the 2005 growing season than in 2003 and 2004. Therefore aflatoxin levels increased slightly for the 2005 crop. The true importance of damage from nematodes, e.g. sting, stubby root and southern root-knot nematodes, is becoming more apparent as growers and county agents become more familiar with the symptoms.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Root & Stalk Rot 0.1 0.08 0.0 0.08
Nematodes 3.0 2.5 0.4 2.9
Mycotoxins 6.0 5.1 0.0 5.1
Leaf Diseases 1.0 0.8 0.1 0.9
Total 10.1 7.76 0.5 8.98
Estimate by Robert Kemerait, Extension Plant Pathologist

Cotton

Many of Georgia's cotton producers celebrated outstanding yields in 2005. Dry weather during the second half of the season led to minimal boll rot and near-perfect conditions at harvest. Cotton was harvested from an estimated 1.22 million acres in 2005. The average lint yield was 762 lb/A. The crop was valued at $723,281,813.

Losses to nematodes, primarily southern root-knot nematodes, continue to be one of the most important problems for cotton growers in Georgia. Until growers are able to practice effective crop rotation and increase the number of years between cotton crops in a field, the losses and damage from parasitic nematodes will continue to increase unless growers use nematicides effectively.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Boll Rot (lint) 1.0 0.7 0.0 0.7
Nematodes 10.0 7.3 9.3a 16.6
Southern root-knot 8.0 5.8
Reniform 1.5 1.1
Columbia lance 0.5 0.4
Seedling Disease 1.0 0.7 2.2b 2.9
Fusarium Wilt Trace
Total 21.0 8.7 11.5 20.2
a This figure is based upon an estimation that approximately 45% of the cotton acreage in the state is treated with a nematicide rate of Temik (5 lb/A or greater) and approximately 2.0% of the acreage was treated with Telone II.
b This figure is an estimate of the cost of fungicides, both in the seed treatments and additional hopper box and in-furrow applications, that are used to manage seedling diseases. For this figure, it is estimated that approximately 15% of the cotton acreage in Georgia is treated with a fungicide in addition to the seed treatment to manage seedling disease.
Estimate by Robert Kemerait, Extension Plant Pathologist

Muscadine Grape

Minimal disease pressure was observed in most muscadine vineyards. When rots were observed, Macrophoma rot was the predominant disease observed. Black rot was observed on leaves, but this did not translate to fruit rots. Moisture levels were extremely high, but disease losses were minimal. Conditions may have helped reduce vine stress, which had been causing vine losses due to secondary dieback diseases.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Bitter Rot 0.1 2.5 40.2 42.7
Macrophoma Rot 1.0 24.6 35.0 59.6
Ripe Rot 0.1 2.5 15.0 17.5
Angular Leaf Spot 0.1 2.5 5.0 7.5
Black Rot 0.1 2.5 0.01 2.5
Phomopsis Dead Arm 0.1 2.5 1.0 3.5
Total 1.5 37.1 96.2 133.3
1 Controlled with fungicides applied for other diseases.
Estimate by Phil Brannen, Extension Plant Pathologist

Ornamentals

The 2005 farm gate value for ornamental horticulture (excluding turfgrass) was estimated at $548.47 million. Landscape, re-wholesale and retail (i.e., service) industries are estimated to account for an additional $800 million, for a total ornamental industry value-added estimated of $1.348 billion. Disease loss estimates were generated for only ornamental production and excludes the value-added service industries as true value, disease loss and cost of control is not documented and varies greatly within the industry. This is a major change from disease loss estimates in previous years as only farm-gate value is reported and figured into the loss estimate.

Root rot diseases still account for the largest percentage of disease loss in commercial ornamental production. Increased detection of Hosta Virus X and Canna yellow mottle virus resulted in higher disease loss due to viruses than in past years. Downy mildews and needle blight on Leyland cypress continue to increase in occurrance and cost of control due to additional fungicide inputs and labor costs.

Disease (ornamental production) % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Bacterial diseases
(fire blight, leaf spots)
0.6 3.29 0.9 4.19
Fungal leaf spots, stem cankers, needle blights 2.8 15.36 6.5 21.86
Root and crown rots 3.0 16.45 8.2 24.65
Powdery mildew 0.6 3.29 1.8 5.09
Botrytis blight 0.3 1.65 1.2 2.85
Virus (TSWV, INSV, CMV) 0.6 3.29 0.1 3.39
Minor diseases (rust, downy mildew, nematode) 1.3 7.13 2.4 9.53
Total (ornamental production) 9.2 50.46 21.1 71.56*

Production Category % Reduction¹
in Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Field Nursery 3.1 3.1 2.1 5.2
Container Nursery 12.7 25.72 10.2 35.92
Floriculture (Greenhouse) 8.8 21.64 8.8 Status and Revision History
Published on Sep 7, 2006
Re-published on Sep 14, 2009
Reviewed on Sep 1, 2012