2000 Georgia Plant Disease Loss Estimates (SB 41-03) University of Georgia Extension It is estimated that 2000 plant disease losses, including control costs, amounted to approximately $572.34 million. The value of the crops used in this estimate was more than $4.376 billion, resulting in a 13.07 percent total disease loss across all crops included in this summary. 2017-03-23 11:55:45.83 2006-06-02 14:35:37.0 2000 Georgia Plant Disease Loss Estimates | Publications | UGA Extension Skip to content

2000 Georgia Plant Disease Loss Estimates (SB 41-03)

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Compiled by: Jean L. Williams-Woodward,
Extension Plant Pathologist

It is estimated that 2000 plant disease losses, including control costs, amounted to approximately $572.34 million. The value of the crops used in this estimate was more than $4.376 billion, resulting in a 13.07 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 Vol. 01, No. 4. Estimates for tobacco are based on Market News Service figures for growers' net sales and do not include warehouse resales. Estimates for vegetables, strawberries, 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 912-386-7495
Phil Brannen Athens, GA 706-542-2685
Tim Brenneman Tifton, GA 912-386-3371
Ed Brown Athens, GA 706-542-2685
Albert Culbreath Tifton, GA 912-386-3370
Barry Cunfer Griffin, GA 770-412-4012
Richard Davis Athens, GA 706-542-2685
Taft Eaker Athens, GA 706-542-9146
Robert Kemerait Tifton, GA 912-386-7495
David Langston Tifton, GA 912-386-7495
Dan Phillips Griffin, GA 770-412-4009
Jean Williams-Woodward Athens, GA 706-542-9146

2000 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- and insect-related plant problems. Plant samples are submitted directly to the county Extension faculty who, at their discretion, forward samples to the appropriate clinic. Commercial turf, fruits, forage crops, greenhouse and ornamental nursery samples are sent to the Plant Disease Clinic in Athens. Diagnoses of and control recommendations for commercial samples of field crops, pecans and vegetables are handled by the Plant Disease Clinic at the Rural Development Center in Tifton, Georgia.

All non-commercial plant samples are sent to the Homeowner IPM Clinic in Athens for disease diagnoses and/or insect 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.

As in 1999, ornamentals (trees, herbaceous and woody landscape plants) and turf comprised most of the samples received in 2000. Total physical plant sample volume was 11.9 percent less than diagnosed in 1999 mostly due to a decrease in homeowner samples. The reduction is most likely because of drought conditions throughout the state. The reduction may also be influenced by an increased use of the Distance Diagnostics through Digital Imaging (DDDI) program. Commercial sample numbers are and have been consistent over the years.

Clinic Summaries: 2000 Plant Specimen Diagnosis
Crop Commercial Samples Homeowner IPM Clinic: Disease Total
Field Crops 242   242
Vegetables 399 101 500
Fruits & Nuts 73 61 134
Herbaceous Ornamentals 282 130 412
Woody Ornamentals 246 265 511
Trees 151 96 247
Turf & Forages 455 465 920
Miscellaneous 6 29 35
TOTAL 1856 1147 3003

Apple

Apples generally had low disease pressure in 2000 until late in the season. Fire blight was virtually nonexistent with the exception of apples produced in south Georgia. The continuing drought conditions allowed for bot (white) rot cankers to increase, particularly in susceptible varieties such as Rome. This could continue to be a major problem over the next 2-3 years for non-irrigated production. Summer rots, particularly bitter rot, were of major concern as the season progressed. The appearance of a possible new, more aggressive Glomerella species was also cause for alarm; we will need to monitor for future outbreaks of this disease. Cost of control included increased pesticide usage for summer rots. Often, chemical fungicides did not adequately suppress disease.

Disease % Reduction in Crop Value Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Fire Blight 0.1 2.6 80.0 82.6
Bitter Rot 5.0 130.3 131.0 261.3
Bot Rot 1.0 26.0 52.0 78.0
Black Rot 0.1 2.6 50.0 52.6
Alternaria Leaf Spot 0.1 2.6 1 2.6
Powdery Mildew 0.1 2.6 18.0 20.6
Sooty Blotch 0.1 2.6 1 2.6
Fly Speck 0.1 2.6 1 2.6
Cedar Apple Rust 0.1 1.3 1 1.3
Scab 0.1 1.3 1.7 3.0
Other Diseases 0.1 1.3 1.0 2.3
Total 6.8 176.0 331.0 507.0
1 Controlled with fungicides applied for other diseases.
Estimated by Phil Brannen, Extension Plant Pathologist.

Blueberry

Blueberry production was up substantially in 2000, with a total production of 19,000,000 lbs. valued at $18.45 million. Mummy berry and rot diseases were observed at very low levels, largely due to dry conditions and good fungicide programs. Botrytis blight was essentially absent as no predisposing freezes occurred during bloom. In southern highbush cultivars, problems due to foliar diseases and dieback continued to be observed. The southern highbush cultivars have incredible market potential, but the leaf spot disease and dieback will have to be addressed.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Mummy Berry 1.5 283.9 500.0 783.9
Botrytis Blight 0.1 18.9 200.0 218.9
Foliar Disease 1.0 189.3 20.0 209.3
Dieback 1.0 189.3 10.0 199.3
Phytophthora Root Rot 0.5 94.6 10.0 104.6
Total 2.6 776.1 740.0 1,516.1
Estimate by Phil Brannen, Extension Plant Pathologist

Bunch Grape

Bunch grape production, predominately wine grapes, has increased dramatically in the north Georgia area within the past two to three years. Disease pressure was low among bunch grape vineyards in 2000, with the exception of Pierce's disease. Dry conditions resulted in very low rot pressure, and mildew pressure was also minimal. Pierce's disease, caused by a bacterial pathogen, was observed at elevations of 1800-2000 feet. This disease is the single most limiting factor associated with production of wine grapes in the southeast. While its appearance at higher elevations is cause for concern, the disease pressure was very low. However, vineyards located at roughly 750 feet were virtually destroyed by this disease (disease incidence of 25-50 percent). The increase in disease may be associated with higher average temperatures, which may have influenced movement and dissemination of the disease by the glassy-winged sharpshooter, a primary vector.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Botrytis 1.0 21.5 20.0 41.5
Downy Mildew 1.0 21.5 15.0 36.5
Black Rot 1.0 21.5 15.0 36.5
Powdery Mildew 1.0 21.5 5.0 26.5
Phomopsis Cane Blight 0.1 2.2 1 2.1
Pierce's Disease 5.0 107.5 5.0 112.5
Total 9.1 195.6 60.0 255.6
1 Controlled with fungicides applied for other diseases.
Estimate by Phil Brannen, Extension Plant Pathologist

Canola

2000 Disease Loss Estimates for Canola Are Not Available. No Canola Was Planted in Georgia in 2000.

Corn

As in 1999, drought continued to cause significant damage to the 2000 corn crop in Georgia. Corn was planted on approximately 400,000 acres in 2000, but harvested from only approximately 300,000 acres. Statewide yields averaged 107 bu/A, and the total crop was valued at $64,200,000. Damage from nematodes in 2000 continued to decline slightly from levels in 1998 and 1999; losses associated with foliar diseases also declined from 1999 due to hot, dry weather. Mycotoxins, especially aflatoxin produced by Aspergillus flavus and closely related fungi, tend to be one of the most serious problems that face corn growers in the state. Contamination by aflatoxin tends to be more severe when the growing season has been hot and dry, when control of insects is insufficient, and when the corn is not properly stored.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Root & Stalk Rot 0.1 0.06 0.0 0.06
Nematodes 2.0 1.3 1.0 2.3
Mycotoxins 10.0 6.4 0.0 6.4
Leaf Diseases 3.5 2.2 0.0 2.2
Total 15.6 9.96 1.0 10.96
Estimate by Robert Kemerait, Extension Plant Pathologist; Richard Davis, Extension Nematologist

Cotton

Cotton was planted on 1.5 million acres in Georgia in 2000 but, due to drought, was only harvested from 1.35 million acres. The average yield was 583 lbs/A with a total production of 1,640,000 bales. The crop was valued at $452,640,000. Boll rot was of less importance in 2000 than it had been in 1999 as a result of hot, dry weather. Damage associated with nematodes was also lower; however, seedling disease increased slightly. Despite the dry weather, seedling disease was common in 2000 and Rhizoctonia solani (soreshin) was nearly always isolated from young, diseased plants. Future increases in soilborne diseases such as Fusarium wilt may result from short crop rotations used by many growers.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Boll Rot (lint) 2.5 11.3 0.0 11.3
Nematodes 4.0 18.1 11.1 29.2
Seedling Disease 1.5 6.8 2.2 9.0
Fusarium Wilt 0.5 2.3 0.0 2.3
Total 8.5 38.5 13.3 51.8
Estimate by Robert Kemerait, Extension Plant Pathologist; Richard Davis, Extension Nematologist

Muscadine Grape

Dry conditions resulted in virtually no disease pressure in most muscadine vineyards. When rots were observed, Macrophoma rot was the predominant "standard" disease observed. Black rot was observed on leaves, but this did not translate to fruit rots. Of interest, Phomopsis dead arm disease was observed in several vineyards. The Granny Val variety has been particularly susceptible to this disease, and some producers are removing this variety completely from their vineyards. The combination of warmer than average winter temperatures and cold damage could help explain the increase in this disease among certain varieties.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Bitter Rot 1.0 20.3 40.2 60.5
Macrophoma Rot 1.0 20.3 35.0 55.3
Ripe Rot 1.0 20.3 15.0 35.3
Angular Leaf Spot 0.1 2.0 5.0 7.0
Black Rot 0.1 2.0 1 2.0
Phomopsis Dead Arm 1.0 20.3 5.0 25.3
Total 4.2 85.3 100.2 185.5
1 Controlled with fungicides applied for other diseases.
Estimate by Phil Brannen, Extension Plant Pathologist

Ornamentals

The estimated value of the ornamental industry (excluding sod) was $1,102,500,000 in 2000. Gross nursery/greenhouse sales were estimated at $291,800,000 with landscape industries making up the bulk of the total ornamental crop value. Root rot diseases account for the largest percentage of disease loss to ornamentals. Foliage disease losses were reduced from 1999 partly due to drought conditions in 2000.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Bacterial diseases
(fire blight, leaf spots)
0.3 3.31 0.9 4.21
Fungal leaf spots, branch and stem cankers 0.4 4.41 5.2 9.61
Root and crown rots 2.0 22.60 7.9 30.50
Powdery mildew 0.2 2.21 1.8 4.01
Botrytis blight 0.1 1.10 1.0 2.10
Virus (TSWV, INSV, CMV) 0.05 0.55 0.0 0.55
Minor diseases (rust, downy mildew, nematode) 0.2 2.21 1.3 3.51
Total 3.3 36.39 18.1 54.49

Production Category % Reduction¹
in Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Field Grown Stock 2.1 1.13 2.0 3.05
Containerized Nursery
(including Liners)
4.8 4.68 4.5 9.18
Floriculture 4.5 6.61 4.2 10.81
Landscape 1.9 13.68 5.3 18.98
Re-wholesale 9.8 10.29 2.1 12.39
Total 3.3 36.39 18.1 54.49
1 This column not additive due to way losses are tabulated.
Estimate by Jean Williams-Woodward, Extension Plant Pathologist

Peach

Peach production in 2000 was excellent (110,000,000 lbs valued at $41.7 million). The dry conditions observed in 2000, when combined with good fungicide programs, resulted in generally low disease pressure. Brown rot incidence was very low. Bacterial spot was not observed, due again to dry conditions. Problems with Armillaria root rot and phony peach were observed. Cost of control included cost of pesticides, equipment and labor. Costs associated with certain cultural practices (flail mowing to reduce gummosis; detailed pruning for control of Phomopsis shoot blight) are directly related to disease control and were therefore considered in the assessment.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Brown Rot 1.5 0.649 1.17 1.82
Scab 0.1 0.043 1.11 1.15
Bacterial Spot 0.01 0.004 0.02 0.02
Phony Peach 1.0 0.433 0.23 0.

Status and Revision History
Published on Nov 17, 2004
Re-published on Feb 10, 2009
Re-published on May 1, 2009
Reviewed on Sep 1, 2012