2001 Georgia Plant Disease Loss Estimates (SB 41-04) University of Georgia Extension It is estimated that 2001 plant disease losses, including control costs, amounted to approximately $587.107 million. The value of the crops used in this estimate was more than $4.799 billion, resulting in a 12.23 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 2001 Georgia Plant Disease Loss Estimates | Publications | UGA Extension Skip to content

2001 Georgia Plant Disease Loss Estimates (SB 41-04)

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

It is estimated that 2001 plant disease losses, including control costs, amounted to approximately $587.107 million. The value of the crops used in this estimate was more than $4.799 billion, resulting in a 12.23 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. 02, No. 04. 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 bertrand@uga.edu
Phil Brannen Athens, GA 706-542-2685 pbrannen@uga.edu
Barry Cunfer Griffin, GA 770-412-4012 bcunfer@griffin.uga.edu
Jan Fowler Athens, GA 706-542-9146 jfowler@uga.edu
Robert Kemerait Tifton, GA 912-386-7495 kemerait@uga.edu
David Langston Tifton, GA 912-386-7495 dlangsto@uga.edu
Alfredo Martinez Griffin, GA 770-228-7375 martinez@griffin.uga.edu
Dan Phillips Griffin, GA 770-412-4009 dphilli@griffin.uga.edu
Jean Williams-Woodward Athens, GA 706-542-9146 jwoodwar@uga.edu

2001 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 2000, ornamentals (trees, herbaceous and woody landscape plants) and turf comprised most of the samples received in 2001. Total physical plant samples diagnoses increased 16 percent over volume in 2000, mostly in the areas of fruits, trees, woody ornamentals and grasses. The increase is most likely due to increased rainfall over 2000, which contributed to an increase in disease in some crops. Although county agents still use the Distance Diagnosis through Digital Imaging system for a more rapid diagnosis of some plant diseases, many agents are not utilizing the system as much as they did in 2000, or they are submitting samples through the DDDI system and then sending the physical sample to the Plant Disease Clinic for confirmation, particularly for homeowner samples.

Clinic Summaries: 2001 Plant Specimen Diagnosis
Crop Commercial Samples Homeowner IPM Clinic Total
Field Crops 262   262
Vegetables 369 135 504
Fruits & Nuts 135 78 213
Herbaceous Ornamentals 247 161 408
Woody Ornamentals 331 346 677
Trees 121 233 354
Grasses 626 484 1110
Miscellaneous 7 41 48
TOTAL 2098 1478 3576

Apple

Apples generally had high disease pressure in 2001. Fire blight was virtually nonexistent due to weather conditions during bloom. Cold damage during bloom substantially reduced apple production, and many orchards were largely abandoned relative to disease control. On remaining apples, summer rots, particularly bitter rot, were of major concern as the season progressed. For the second year in a row, a more aggressive Glomerella species was observed, and the disease resulted in severe defoliation of apple trees where it occurred. 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 2.3 40.0 42.3
Bitter Rot 10.0 229.3 100.0 329.3
Bot Rot 1.0 22.9 52.0 74.9
Black Rot 0.1 2.3 33.0 35.3
Alternaria Leaf Spot 0.1 2.3 1 2.3
Powdery Mildew 0.1 2.3 11.5 13.8
Sooty Blotch 0.1 2.3 1 2.3
Fly Speck 0.1 2.3 1 2.3
Cedar Apple Rust 0.1 2.3 1 2.3
Scab 0.05 1.1 1 1.1
Other Diseases 0.05 1.1 1.0 1.1
Total 11.8 270.5 237.5 507.0
1Controlled with fungicides applied for other diseases.
Estimated by Phil Brannen, Extension Plant Pathologist.

Blueberry

Blueberry production was down in 2001, with a total production of 17,000,000 lbs. valued at $13.5 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 were 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 1.5 211.6 500.0 711.6
Botrytis Blight 0.1 14.1 200.0 214.1
Foliar Disease 1.0 141.0 20.0 161.1
Dieback 1.0 141.0 10.0 151.1
Phytophthora Root Rot 0.5 70.5 10.0 80.5
Total 4.1 578.2 740.0 1,318.4
Estimate by Phil Brannen, Extension Plant Pathologist

Bunch Grape

Bunch grape production, predominantly wine grapes, continues to increase in the north Georgia area. Disease pressure was very high among bunch grape vineyards in 2001. Wet conditions resulted in very high rot pressure, and mildew pressure was also high. Pierce's disease, caused by a bacterial pathogen, was observed at elevations of 1800-2000 feet, but disease levels did not increase. Crown gall, also caused by a bacterial pathogen, did increase as a result of cold-damaged vines. Pathological issues resulted in a substantial value loss in 2001.

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Botrytis 5.0 98.3 30.0 128.3
Downy Mildew 2.0 39.3 20.0 59.3
Black Rot 1.0 19.7 20.0 39.7
Powdery Mildew 5.0 98.3 5.0 103.3
Phomopsis Cane Blight 2.0 39.3 1 39.3
Crown Gall 1.0 19.7 5.0 24.7
Pierce's Disease 1.0 19.7 5.0 24.7
Total 17.0 334.3 85.0 419.3
1 Controlled with fungicides applied for other diseases.
Estimate by Phil Brannen, Extension Plant Pathologist

Canola

2001 Disease Loss Estimates for Canola Are Not Available. No Canola Was Planted in Georgia in 2001.

Corn

Conditions were better for corn production in Georgia in 2001 than they had been for several years. Rainfall was generally favorable for crop production across many areas of the state and led to increased yields from 2000. In 2001, corn was planted on 265,000 acres and harvested from 220,000 acres. The yield was 134 bu/A, up from 107 bu/A in 2000. The 2001 crop was valued at $63,382,000. In 2001, foliar diseases, especially southern corn leaf blight, caused by Bipolaris maydis, were common. This increase was closely linked to locally abundant rainfall that created conditions favorable for disease development. Wetter conditions during the season should have helped to reduce the level of aflatoxin, caused by Aspergillus flavus, as production of this mycotoxin is favored by hot, dry weather.

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 1.26 1.0 2.26
Mycotoxins 7.5 4.75 0.0 4.75
Leaf Diseases 5.0 3.17 0.0 3.17
Total 14.6 9.24 1.0 10.24
Estimate by Robert Kemerait, Extension Plant Pathologist

Cotton

Increased rainfall during the 2001 season helped boost yields in last season's crop. Cotton was planted on 1.5 million acres in 2001 and harvested from an estimated 1.49 million acres. The average lint yield was 709 lb/A for a total production of 2.2 million bales. the crop was valued at $370,656,000. Losses to boll rot increased in 2001 from 2000 because of the locally abundant rainfall in some areas of the state. Seedling disease was also more common for the same reason. Seedling disease in Georgia is largely Rhizoctonia solani (soreshin); however, there is evidence that Pythium spp. may play a greater role in this disease complex than previously thought. Losses to nematodes, primarily southern root-knot and reniform, increased slightly in 2001, partly as a result of inadequate crop rotation in some areas.

Disease % Reduction in
Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Boll Rot (lint) 5.0 18.5 0.0 18.5
Nematodes 5.0 18.5 12.0 30.5
Seedling Disease 3.0 11.1 2.211 13.3
Fusarium Wilt 0.1 0.4 0.0 0.4
Total 13.1 48.5 14.2 62.7
1 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

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 increased to epidemic levels in several vineyards, resulting in 50-75 percent losses in some varieties. 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 years of drought stress 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 18.2 40.2 58.4
Macrophoma Rot 1.0

18.2

35.0 53.2
Ripe Rot 1.0 18.2 15.0 33.2
Angular Leaf Spot 0.1 1.8 5.0 6.8
Black Rot 0.1 1.8 1 1.8
Phomopsis Dead Arm 5.0 90.0 5.0 95.9
Total 8.2 149.1 100.2 249.3
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 $1.473.2 million in 2001. Gross field and container nursery/greenhouse sales were estimated at $410.5 million with landscape industries (including re-wholesalers) making up the bulk of the total ornamental crop value. Root rot diseases account for the largest percentage of disease loss to ornamentals. Daylily rust, which was first seen in Georgia in fall 2000, became more widespread in 2001, which increased cost of control for nurseries, re-wholesalers and landscapers.

Disease % Reduction in Crop Value Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Bacterial diseases
(fire blight, leaf spots)
0.2 2.95 0.8 3.75
Fungal leaf spots, branch and stem cankers 0.5 7.37 6.3 13.67
Root and crown rots 2.3 33.88 8.1 41.98
Powdery mildew 0.2 2.95 1.8 4.75
Botrytis blight 0.1 1.47 1.0 2.47
Virus (TSWV, INSV, CMV) 0.05 0.73 0.0 0.73
Minor diseases (rust, downy mildew, nematode) 1.3 19.15 2.1 21.25
Total 4.65 68.5 20.1 88.63

Production Category % Reduction1
in Crop Value
Damage
($ Millions)
Cost of Control
($ Millions)
Total
($ Millions)
Field Grown Stock 2.8 1.90 2.0 3.90
Containerized Nursery
(including Liners)
7.1 11.21 5.4 16.61
Floriculture 6.1 11.28 4.3 15.58
Landscape 2.8 25.71 5.6 52.87
Re-wholesale 12.8 18.43 2.8 21.23
Total 4.65 68.5 20.1 88.63
1 Values in this column are not additive and are calculated as the % reduction in crop value per grower category.
Estimate by Jean Williams-Woodward, Extension Plant Pathologist

Peach

Peach production in 2001 was greatly reduced over its potential due to disease issues. The wet conditions observed in 2001 often resulted in increased disease and poor fungicide programs. Brown rot incidence was extremely high as was bacterial spot and scab. 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.

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

Disease % Reduction in
Crop Value
Damage
($ Thousands)
Cost of Control
($ Thousands)
Total
($ Thousands)
Brown Rot 10.0 4,279.0 1,500.0 5,779.3