Soils and Fertilizers

Table III-1. Common Incomplete Fertilizers or Farm-Type Fertilizers

Fertilizer	%N	%P2O5	%K2O
Ammonium Nitrate	34	0	0
>Ammonium Sulfate	21	0	0
Monoammonium Phosphate	11	48	0
Muriate of Potash (potassium chloride)	0	0	60
Potassium Sulfate	0	0	52
Super Phosphate	0	20	0
Triple Super Phosphate	0	45	0
Urea	46	0	0
Urea-ammonium nitrate (liquid)	32	0	0

Table III-2. Comparison of Conventional and Slow Release Fertilizers

Type of Fertilizer	Advantages	Disadvantages
Slow Release Fertilizer	Fewer applications Low burn potential Release rates vary depending on fertilizer characteristics Comparatively slow release rate	Unit cost is high Availability limited Release rate governed by factors other than plant needed Regulated by temperature
Conventional Fertilizer	Fast acting Most are acid forming Low cost	Greater burn potential Solidifies in the bag when wet N leaches readily
Manures or Sewage Sludge	Low burn potential Relatively slow release Contains micronutrients Conditions soil	Salt and/or sodium could be a problem Bulky, difficult to handle Odor Expensive per pound of actual nutrient Weed seeds a problem Heavy metals may be present in sewage sludge if not classified as Class A sludge (more frequent in sludge from large cities) Application at the nitrogen rate over several years will lead to a buildup of phosphorous

Table III-3. Approximate Nutrient Content of Manures and Suggested Yearly Rates of Application per 1,000 Square Feet of Area

Manure Type(dry)	% N	% P2O5	% K2O	Suggested amounts of material (lb per 1000 sq. ft)
Chicken Manure	2.0 – 4.5	4.6 – 6.0	1.2 – 2.4	125
Steer Manure	0.6 – 2.5	0.9 – 1.6	2.4 – 3.6	450
Dairy Manure	0.6 – 2.1	0.7 – 1.1	2.4 – 3.6	600

* Cut rates by 50% if soils are saline, or water has a medium to high salinity hazard.

Table III-4. A List of Commonly Used Fertilizers and Salt Index or Burn Potential

Material	Analysis	Burn Potential per Equal Weights of Material
Ammonium Nitrate	33% N	104.7
Ammonium Sulfate	21% N	69.0
Potassium Nitrate	14% N	73.6
Urea	46% N	75.4
URAN	32% N	74.2
Concentrated Super Phosphate	45% P2O5	10.1
Diammonium Phosphate	21% N; 54% P2O5	34.2
Superphosphate	20% P2O5	7.8
Potassium Chloride	60% K2O	116.3
Potassium Sulfate	54% K2O	46.1
Dolomite	30% Calcium Oxide 20% Magnesium Oxide	0.8
Gypsum	33% Calcium Oxide	8.1
Epsom Salt	16% Magnesium Oxide	44.0
Salt Index	Sodium Nitrate	100

Table III-5. Crop Response to Salinity

Salinity (expressed as ECCE, mmho/cm, or dS/m)	Crop Response
0 – 2	Salinity effects mostly negligible
2 – 4	Yields of very sensitive crops may be restricted
4 – 8	Yields of many crops restricted
8 – 16	Only tolerant crops yield satisfactorily
> 16	Only a few very tolerant crops yield satisfactorily

Cultural Practices

Table IV-1. Relative Vegetable Water Needs

Seasonal Water Demand	Crop	Approximate Demand (inch)
High	Broccoli	20 – 25
	Cabbage	20 – 25
	Cauliflower	20 – 25
	Slicer Cucumber	20 – 25
	Eggplant	20 – 35
	Onion	25 – 30
	Pepper	25 – 35
	Potato	20 – 40
	Pumpkin	25 – 30
	Sweet corn	20 – 35
	Tomato	20 – 25
Moderate	Asparagus	10 – 18
	Pinto Bean	15 – 20
	Cantaloupe	15 – 20
	Cowpea	10 – 20
	Pickling cucumber	15 – 20
Low	Lettuce	8 – 12
	Mustard greens	10 – 15
	Radish	5 – 6
	Spinach	10 -15
	Turnip	10 – 15
	Watermelon	10 – 15

Table IV-2. Nitrogen Requirements for Fertigation of Vegetable Crops

Crop	Growth Stage	N required (lb/A/week)
Broccoli	Early Growth	5 – 101
	Midseason	10 – 20
	Button Formation	15 – 30
	Head Development	10 – 20
Cucumber	Vegetative Growth	5 – 10
	Early Flowering/Fruit Set	10 – 20
	Fruit Bulking	10 – 15
	First Harvest	5 – 10
Lettuce	Early Growth	5 – 10
	Cupping	10 – 20
	Head Filling	15 – 30
Melon	Vegetative Growth	5 – 10
	Early Flowering/Fruit Set	10 – 20
	Fruit Bulking	10 – 15
	First Harvest	5 – 10
Pepper	Vegetative Growth	5 – 10
	Early Flowering/Fruit Set	15 – 30
	Fruit Bulking	15 – 20
	First Harvest	5 – 10
Squash	Vegetative Growth	5 – 10
	Early flowering	10 – 20
	First Harvest	5 – 10
Tomato	Vegetative Growth	5 – 10
	Early Flowering/Fruit Set	15 – 20
	Fruit Bulking	10 – 15
	First Harvest	5 – 10

¹ Higher values represent fertilization needs in soils with small amounts of residual nitrogen or where higher temperatures causes rapid plant growth
Source: Hartz, T. K. 1993. Drip irrigation and fertigation management of vegetable crops. Department of Vegetable Crops, University of California, Davis

Table IV-3. Degree of Toxicity of Pesticides on Honeybees

Highly Toxic: Severe bee losses can be expected if the following materials are used when honeybees are present at treatment time or within a day thereafter.	Moderately Toxic: These can be used in the vicinity of honeybees if the dosage, timing, and method of application are correct. However, they should not be applied directly on honey bees in the field or at the hives.	Relatively Non-Toxic: This group of materials can be used with a minimum of injury.
chlorpyrifos (Lorsban)	disulfoton (Di-Syston)	Bacillus thuringiensis (Dipel)
carbofuran (Furadan)	endosulfan (Thiodan)	dicofol (Kelthane Miticide)
Parathion	phorate (Thimet)	Pyrethrum
dimethoate (dimethoate)	oxamyl (Vydate)	Rotenone
methidathion (Supracide)		Trichlorfon
methyl parathion (Penncap-M)
diazinon (Diazinon)
azinphosmethyl (Guthion)
naled (Dibrom)
malathion (Cythion, Malathion)
phosmet (Imidan)
acephate (Orthene)
carbaryl (Sevin)
methamidophos (Monitor)

Adapted from the Indiana Vegetable Production Guide for Commercial Growers.

Irrigation

Table V-1. Principal Data Needed for Farm Irrigation System Design

Data	Specific Requirements
Crop	Distribution and area of each crop to be grown; Suitability of each crop to climate, soils, farming practices, markets; Planting dates for each crop to be grown over the expected life of the project
Soil	Area distribution of soils, Water holding and infiltration characteristics, Depth, Drainage requirements, Salinity, Erosion potential of each soil
Water Requirement	Data for estimating daily and seasonal water requirements for each crop
Water Supply	Location of water source, Amount of water or pumping capacity, water surface elevation; Hydrologic and water quality information for assessing the availability, costs, and suitability of the water for irrigation; Water rights information
Energy Source	Location, availability, and type of source(s); Cost information
Capital and Labor	Capital available for system development, Level of technical skill, Cost of labor
Other	Topographic map showing location of roads, buildings, drainways, and other physical features that influence design, financial situation of farmer, or farmer preferences

Table V-2. Typical Overall On-farm Efficiencies for Various Types of Irrigation Systems (adapted from James, 1988)

System	Overall Efficiency (%)
Surface a) Average b) Land leveling and delivery pipeline meeting design standards c) Tail water recovery with (b) d) Combination level and graded flow irrigation (max 0.1% grade and block ends) e) Surge	50 – 80 50 70 80 80 – 95 60 – 90
Sprinkler	55 – 75
Center Pivot	55 – 75
LEPA a) Bubble Mode b) Spray Mode	95 – 98 80 – 85
Drip	80 – 90

* Surge has been found to increase efficiencies 8 to 28% over nonsurge furrow systems.
** Trickle systems are typically designed at 90% efficiency, short laterals (< 100 ft) or systems with pressure compensating emitters may have higher efficiencies

Table V-3. Comparison of Irrigation Systems in Relation to Site and Situation Factors

Site and Situation Factors	Well-Designed Surface Systems	Level Basins	Intermittent* Mechanical Move	Continuous** Mechanical Move	Solid Set and Permanent	Emitters and Drip Tubing
Infiltration Rate	Moderate to low	Moderate	All	Medium to high	All	All
Topography	Moderate slopes	Small slopes	Level to rolling	Level to rolling	Level to rolling	All
Crops	All	All	Generally shorter crops	All but trees and vineyards	All	High value required
Water Supply	Large streams	Very large streams	Small streams nearly continuous	Small streams nearly continuous	Small streams	Small streams continuous and clean
Labor Requirement	High, training required	Low, some training	Moderate, some training	Low, some training	Low to seasonal high, little training	Low to high, some training
Capital Requirement	Low to moderate	Moderate	Moderate	Moderate	High	High
Energy Requirement	Low	Low	Moderate to high	Moderate to high	Moderate	Low to moderate
Management Skill	High	Moderate	Moderate	Moderate	Moderate	High
Windy Conditions	Good	Good	Poor	Poor to excellent***	Fair	Fair to excellent

* Side roll, big guns, etc.
** Center pivot
*** Depends on type of water applicators
Adapted from: G.O. Schwab, R.K. Frevert, T.W. Edminster, and K.K. Barnes, Soil and Water Conservation Engineering, 1981. John Wiley & Sons, Inc., New York, pp 430-431.

Table V-4. Annual Maintenance, Repairs, and Depreciation for Irrigation System Components

Component	Depreciation (hours)	Period (year)	Annual Maintenance and Repair Percent of Initial Cost
Wells and Casings	–	20 – 30	0.5 – 1.5
Pumping Plant Structure
Pump, Vertical Turbine	–	20 – 40	0.5 – 1.5
Bowls	16,000 – 20,000	8 – 10	5 – 7
Column, etc.	32,000 – 40,000	16 – 20	3 – 5
Pump, Centrifugal	32,000 – 50,000	16 – 25	3 – 5
Power Transmission: Gear Head	30,000 – 36,000		5 – 7
V-belt	6,000	3	5 – 7
Flat Belt, Rubber and Fabric	10,000	5	5 – 7
Flat Belt, Leather	20,000	10	5 – 7
Prime Movers: Electric Motor	50,000 – 70,000	25 – 35	1.5 – 2.5
Diesel Engine	28,000	14	5 – 8
Gasoline Engine: Air Cooled	8,000	4	6 – 9
Water Cooled Engine	18,000	9	5 – 8
Propane Engine	28,000	14	4 – 7
Open Farm Ditches (permanent)		20 – 25	0.5 – 1.0
Concrete Structure		20 – 40	0.5 – 1.0
Pipe: Asbestos, Cement, PVC (buried)		40	0.25 – 0.75
Aluminum (surface)		10 – 12	1.5 – 2.5
Steel, waterworks class, (buried)		40	0.25 – 0.50
Steel, coated and lines, (buried)		40	0.25 – 0.50
Steel, coated (buried)		20 – 25	0.50 – 0.75
Steel, coated, (surface)		10 – 12	1.5 – 2.5
Steel, galvanized (surface)		15	1.0 – 2.0
Steel, coated and line (surface)		20 – 25	1.0 – 2.0
Wood (buried)		20	0.75 – 1.25
Aluminum, sprinkler use (surface)		15	1.5 – 2.5
Reinforced Plastic Mortar (buried)		40	0.25 – 0.50
Plastic (trickle, surface)		10	1.5 – 2.5
Sprinkler Head		8	5 – 8
Drip Emitters		8	5 – 8
Drip Filters		12 – 15	6 – 9
Land Grading		None	1.5 – 2.5
Reservoirs		None	2.0 – 2.0
Mechanical Move Sprinklers		12 – 16	5 – 8

Source: G.T. Thompson, L.B. Spiess, and J.N. Krider, Farm Resources and System Selection, In Design and Operation of Farm Irrigation, Systems, 1980, M.E. Jensen (Ed.) ASAE Monograph 3, St. Joseph, MI, p. 45

Table V-5. Required Flow Rate Capacity of Irrigation Wells
inch/day

gpm/acre	inch/week	Inches in Irrigation Days
		30	45	60	80	100
1.5	0.55	0.08	2.4	3.8	4.8	6.4	8
2	0.75	0.11	3.2	4.8	6.4	8.5	10.6
2.5	0.93	0.13	4	6	8	10.6	13.3
3	1.1	0.16	4.8	7.2	9.5	12.7	15.9
3.5	1.3	0.18	5.6	8.3	11.1	14.8	18.6
4	1.5	0.21	6.4	9.5	12.7	17	21.2
4.5	1.67	0.24	7.2	10.7	14.3	19.1	23.9
5	1.85	0.27	8	11.9	15.9	21.2	26.5
5.5	2	0.29	8.7	13.1	17.5	23.3	29.2
6	2.25	0.32	9.5	14.3	19.1	25.4	31.8
6.5	2.41	0.34	10.3	15.5	20.7	27.5	34.4
7	2.6	0.37	11.1	16.7	22.6	29.7	37.1

Table V-6. Approximate Maximum Flow Rate in Different Pipe Sizes to keep Velocity at 5 ft/sec

Pipe Diameter (inch)	Flow Rate (gpm)	Pipe Diameter (inch)	Flow Rate (gpm)
½	6	4	200
¾	10	5	310
1	15	6	440
1¼	25	8	780
1½	35	10	1225
2	50	12	1760
3	110	16	3140

Table V-7. Approximate Friction Losses in Feet of Head per 100 Feet of Pipe

Pipe size	4-inch			6-inch			8-inch			10-inch			12-inch
	Steel	Alum.	PVC	Steel	Alum.	PVC	Steel	Alum.	PVC	Steel	Alum.	PVC	Steel	Alum.	PVC
Flow Rate (gpm)
100	1.2	0.9	0.6	–	–	–	–	–	–	–	–	–	–	–	–
150	2.5	1.8	1.2	0.3	0.2	0.2	–	–	–	–	–	–	–	–	–
200	4.3	3.0	2.1	0.6	0.4	0.3	0.1	0.1	0.1	–	–	–	–	–	–
250	6.7	4.8	3.2	0.9	0.6	0.4	0.2	0.1	0.1	0.1	0.1	–	–	–	–
300	9.5	6.2	4.3	1.3	0.8	0.6	0.3	0.2	0.1	0.1	0.1	–	–	–	–
400	16.0	10.6	7.2	2.2	1.5	1.0	0.5	0.3	0.2	0.2	0.1	0.1	0.1	–	–
500	24.1	17.1	11.4	3.4	2.4	1.6	0.8	0.6	0.4	0.3	0.2	0.1	0.1	0.1	0.1
750	51.1	36.3	24.1	7.1	5.0	3.4	1.8	1.3	0.8	0.6	0.4	0.3	0.2	0.1	0.1
1000	87.0	61.8	41.1	12.1	8.6	5.7	3.0	2.1	1.4	1.0	0.7	0.5	0.4	0.3	0.2
1250	131.4	93.3	62.1	18.3	3.0	8.6	4.5	3.2	2.1	1.5	1.1	0.7	0.6	0.4	0.3
1500	184.1	130.7	87.0	25.6	18.2	12.1	6.3	4.5	3.0	2.1	1.5	1.0	0.9	0.6	0.4
1750	244.9	173.9	115	34.1	24.2	16.1	8.4	6.0	4.0	2.8	2.0	1.3	1.2	0.9	0.6
2000	313.4	222.5	148.1	43.6	31.0	20.6	10.8	7.7	5.1	3.6	2.6	1.7	1.5	1.1	0.7

Note: Flow rates below horizontal line for each pipe size exceed the recommended 5 ft per second velocity.

Table V-8. Interpretation of Tensiometer Readings for Vegetables

	Dial Reading in Centibars	Interpretation
Nearly saturated	0	Nearly saturated soil often occurs for a day or two following irrigation. Danger of water-logged soils, a high water table, poor soil aeration, or the tensiometer may have broken tension if readings persist.
Field capacity	10	Field capacity. Irrigations discontinued at field capacity to prevent waste by deep percolation and leaching of nutrients below the root zone.
Irrigation range	20	Usual range for starting irrigations. Most of the available soil moisture is used up in sandy loam soils. For clay loams, only one or two days of soil moisture remain.
Dry	30 80	This is the stress range for most vegetable crops. Top range of accuracy of tensiometer. Readings above this are possible but many tensiometers will break tension between 80 to 85 centibars.

Table V-9. Maximum Water Infiltration Rate in Various Soil Types

Soil Type	Infiltration Rate (inch/hr)*
Sand	2
Loamy sand	1.8
Sandy loam	1.5
Loam	1
Silt and clay loam	0.5
Clay	0.2

* Assumes a full crop cover. Bare soil rate is ½ of full crop cover

Table V-10. Recommended Chemical Treatments for Selected Conditions

Water Quality	Suggested Treatment
Ca > 50 ppm Mg > 50 ppm	Hard water, caused by high ppm concentrations of Ca or Mg, can reduce flow rates by the buildup of scales on pipe walls and emitter orifices. Periodic injection of an HCl solution may be required throughout the season. Lower concentrations of Ca and Mg may require HCl treatment every few years.
Fe > 0.5 ppm S > 0.5 ppm	Iron and sulfur, as well as other metal contaminants, provide an environment in water that is conducive to bacterial activity. The by-products of the bacteria in combination with the fine (less than 100-micron) suspended solids can cause system plugging. Bacterial activity can be controlled by chlorine injection and line flushing on a regular basis throughout the irrigation season. Bacterial activity is prevalent in Fe and S concentrations S over 0.5 ppm, but may also occur at lower concentrations.

Source: British Columbia Ministry of Agriculture, Water Treatment Guidelines for Trickle Irrigation, Engineering Reference Information R512.000, 1982. 2 pp.

Table V-11. Possible Causes of Changes in Irrigation System Flow

Increased Flow	Improperly adjusted gates, valves, checks Pipeline leaks and breaks Pressure downstream of pressure regulators is too high Worn or oversize sprinkler nozzles, emission devices, etc. System on too long (as indicated by higher than expected volumes of flow)
Decreased flow	Improperly adjusted gates, valves, checks Clogged sprinklers, emission devices, screens, filters, etc. Pressure downstream of pressure regulators too low. Existence of entrapped air in the system System not on long enough (as indicated by lower than expected volumes of flow)

Insect Management

Table VI-1. Vegetable Varieties that have shown Some Resistance to Specific Insect Pests

Vegetable	Variety	Insect resistance
Bean (snap)	Wade	Striped Flea Beetle
Broccoli	De Cicco	Striped Flea Beetle
Cabbage	Early Globe Red Acre Round Dutch	Cabbage Looper, Imported Cabbageworm Cabbage Looper, Imported Cabbageworm Cabbage Looper, Imported Cabbageworm
Cabbage (Chinese)	Michihili	Diamondback Moth
Collard	Georgia	Striped Flea Beetle, Harlequin Bug
Corn (sweet)	Golden Security	Corn Earworm
Cucumber	Ashley Piccadilly Poinsett	Pickleworm, Spotted Cucumber Beetle Pickleworm Spotted Cucumber Beetle
Kale	Vates	Diamondback Moth
Mustard	Florida Broadleaf	Diamondback Moth, Striped Flea Beetle
Radish	Cherry Belle White Icicle	Diamondback Moth, Harlequin Bug Harlequin Bug
Squash	Early Prolific Straightneck White Bush Scallop Zucchini	Pickleworm, Striped Cucumber Beetle Pickleworm, Striped Cucumber Beetle Striped Cucumber Beetle
Sweetpotato	Centennial Jewel	Sweetpotato Flea Beetle, Potato Wireworm Sweetpotato Flea Beetle, Potato Wireworm
Turnip	Seven Top	Diamondback Moth, Striped Flea Beetle
Rutabaga	American Purple Top	Diamondback Moth, Striped Flea Beetle

Disease Management

Table VII-1 Characteristics to evaluate when Diagnosing Diseases

General Symptoms	Specific Symptoms	Possible Causes
Distribution in the Field	Symptoms observed over a wide area on several crops	Soil Problem Low Fertility Insect Injury Physiological Problem
	Symptoms observed over a wide area on a single crop	Soil Problem Low Fertility Insect Injury Virus Foliage Pathogen (advanced stage of epidemic)
	Symptoms observed scattered over a field on a single crop	Soilborne Root Rot Fungi Soilborne Wilt Organisms Nematodes Virus Foliar Pathogens Soil Problem Insect Injury
Foliage symptoms	General yellowing	Wet Soil Low Fertility Root Rot Pathogens Nematodes
	Necrotic spots on leaves	Spots Generally Round (Fungal leafspot) Spots Generally Angular (Bacterial leafspot)
	White powdery substance on leaf surface	Powdery Mildew
	Light yellow spot on upper leaf surface downy growth on lower surface	Downy Mildew
	Ruptured areas on lower leaf surface	White in center of ruptured area (White Rust) Reddish brown to orange in center of ruptured area (Rust)
	Light and dark green areas on a leaf	Appears in a random pattern in the field (Virus) Appears in rows (Nutrient Deficiency)
	Leaves distorted	Virus Herbicide
	Leaves with holes or chewed areas	Insect Injury
	Leaves yellow, wilt and die	Root decayed (Root Rot) Brown ring in vascular portion of root (Fusarium Wilt) Roots cut or damaged by feeding (Insects; Gophers or Moles) Damage in low areas of field (Root Rot; Poor Drainage)
Root Symptoms	Roots decayed	Root Rot Poor Drainage
	Roots with discoloration beneath outer layer	Fusarium Wilt
	Swellings on roots and stem	Large swelling (Crown Gall Bacterium) Small swellings which appear in a random patter on roots (Root Knot Nematode) Small swelling at root tips (Dagger Nematode)
	Root tips dead	Isolated areas (Nematodes; Fertilizer Burn) Affected area is in a pattern or over the general field (Fertilizer Burn)
	Roots dead with white fungal strands around the stem at the soil line	Southern Blight
Fruit Symptoms	Fruit decay scattered over fruit surface	Watery soft decay, foul odor (Bacterial Soft Rot) Firm to watery soft rot (Fungal Decay)
	Hard black decay at blossom end	Blossom end rot (Nutrient and Water Problem)
	Fruit distorted	Virus Insects
	Faint rings visible on fruit	Virus
	Light colored blotchy appearance	Insects
	Dark raised areas on fruit	Bacterial Leafspot

Table VII-2. Grouping of Vegetables based on Susceptibly to Similar Diseases

Group A	Group B	Group C	Group D	Group E	Group F	Group G
Cucurbitaceous	Cruciferous	Solanaceous	Beets	Leguminous	Onions	Sweet Corn
Watermelon	Cabbage	Pepper	Swiss Chard	Beans	Garlic
Pumpkin	Radish	Tomato	Spinach	Southern Peas	Leek
Cucumber	Cauliflower	Irish Potato		English Peas	Shallot
Squash	Broccoli	Eggplant		Snow Peas
Cantaloupe	Brussels Sprouts
Honeydew Melon	Mustard
Cushaw	Collards
	Chinese Cabbage
	Pak Choi

Table VII-3. Common Diseases of Specific Vegetables and their Control

Crop	Disease	Control
Beans, Snap	Southern Blight	Apply preplant soil fungicide Deep burial of crop residue
	Damping Off	Planting at soil temperature > 60°F Plant on raised beds Plant treated seed Apply preplant soil fungicide
	Bean Mosaic (virus)	Virus-free seed Resistant cultivars
	Bacterial Blight	Pathogen-free seed Apply copper fungicides Two year crop rotation
	Cercospora and other Fungal Leafspots	Apply fungicides as needed Two year crop rotation
	White Mold	Apply fungicides as needed Wide row spacing and orientation to favor drying of the canopy
	Rust	Apply fungicides as needed Crop rotation Resistant cultivars
Cabbage, Cauliflower, Broccoli, Kale	Black Rot	Plant hot water treated seed Plant resistant varieties Plant on raised bed to avoid flooding Two year crop rotation
	Downy Mildew	Plant resistant varieties Apply fungicides as needed
	Alternaria Leafspot	Apply fungicides as needed
Cucurbits: Watermelon, Pumpkin, Cantaloupe, Squash, Cucumber, Cushaw	Fusarium Wilt	Crop rotation (5+ years) Resistant cultivars
	Powdery Mildew	Resistant cultivars Apply fungicides as needed
	Downy Mildew	Resistant cultivars Apply fungicides on a preventative basis
	Anthracnose (watermelon, cucumber, cantaloupe)	Resistant cultivars Crop rotation Apply fungicides on a preventative basis
	Alternaria Leafspot, Cercospora Leafspot	Apply fungicides as needed Two year crop rotation
	Angular Leafspot	Pathogen-free seed Apply copper fungicides Avoid overhead irrigation
	Bacterial Wilt (cucumber)	Control beetle vector Resistant cultivars
	Fruit Blotch (watermelon)	Pathogen-free seed Copper fungicides Two year crop rotation Avoid overhead irrigation
	Gummy Stem Blight	Two year crop rotation Apply fungicides on a preventative basis
	Choanephora Wet Rot	Frequent sprays of blossoms with copper fungicides Keep fruit cool and dry after harvest
	Virus Diseases	Resistant cultivars
Carrot	Bacterial Soft Rot	Minimize injury during harvesting, grading and packing. If carrots are washed after harvesting, they can be dipped in a 1:500 solution of sodium hypochlorite (5.25%) Store at a temperature just above 32°F.
	Crown Rot	Crop rotation (4 to 5 years)
	Cercospora or Alternaria Leaf Blight	Apply fungicides as needed
	Aster Yellows	Control leafhoppers Control weeds in and around fields
Corn, Sweet & Pop	Northern Corn Leaf Blight	Burial of crop residue Apply fungicides as needed
	Rusts (Common, Southern)	Resistant cultivars Crop rotation Burial of crop residue
	Downy Mildew	Metalaxyl/mefenoxam seed treatment Do not plant on land subject to flooding Do not plant sweet corn following sorghum Two year crop rotation
	Common Smut	Resistant cultivars
	Maize Dwarf Mosaic Virus	Resistant or tolerant cultivars Eradication of johnsongrass in and around the field
Eggplant	Southern Blight	Deep burial of crop residue Crop rotation (do not follow beans, tomatoes, southern peas, okra or peanuts)
	Verticillium Wilt	Soak seed for 20 minutes in 120°F water
	Phomopsis Blight	Resistant cultivars Pathogen-free seed Three year crop rotation Apply fungicides as needed
Lettuce	Bacterial Soft Rots	Plant in well-drained soil Use furrow or drip irrigation
	Downy Mildew	Resistant cultivars Three year crop rotation Apply fungicides as needed
	Bottom Rot	Do not plant lettuce following tomatoes, Irish potatoes, or beans Plant on wide, raised beds Deep burial of crop residue Apply fungicides as needed
	Sclerotinia Drop	Follow long rotations Plant on well-drained soil Use furrow or drip irrigation; Resistant cultivars Apply fungicides as needed
	Lettuce Mosaic	Control weeds in and around the field Plant only Mosaic Indexed seed (MTO) Resistant cultivars
Mustard, Turnip, Radish	White Rust & Downy Mildew	Apply fungicides as needed Crop rotation Burial of crop residue
	Anthracnose & Cercospora Leafspot	Two year crop rotation Apply fungicides as needed
Onion, Garlic, Shallot	Pink Root	Resistant cultivars
	Purple Blotch	Crop rotation Apply fungicides as needed
	Botrytis Leaf Blight	Apply fungicides as needed
Pea (English, Sugar Snap, Edible Pod)	Fusarium and Pythium Root Rot	Crop rotation
	Powdery Mildew	Apply fungicides as needed Resistant cultivars
Pepper (Bell and Hot)	Phytophthora Blight	Plant on well-drained soil Plant on raised beds Apply fungicides as needed
	Cercospora Leafspot	One year crop rotation Apply fungicides as needed
	Powdery Mildew	Apply fungicides as needed
	Viruses (several)	Control weeds in and around field Resistant cultivars
	Bacterial Spot	Resistant cultivars Apply copper bactericides
Potato	Black Leg	Avoid excessive irrigation Avoid washing seed potatoes
	Common Scab	Maintain high soil moisture before and after tuber set
	Early Blight	Apply fungicides as needed
	Late Blight	Preventative applications of fungicides
	Viruses	Plant virus-free seed
Spinach, Swiss Chard	Fusarium Wilt	Long crop rotation
	White Rust	Three year crop rotation Apply fungicides as needed Burial of crop residue Resistant cultivars
	Downy Mildew	Crop rotation Soil treatment with metalaxyl or mefenoxam Resistant cultivars Burial of crop residue
	Fungal Leafspots	Apply fungicides as needed Crop rotation Burial of crop residue
	Viruses (several)	Resistant cultivars Control weeds in and around the field
Sweetpotato	Scurf	Do not use manure where sweet potatoes are to be planted Plant slips from disease free roots Crop rotation
	Southern Blight	Deep burial of crop residue Crop rotation
	Black Rot	Plant clean slips clipped 1 inch above the soil line Crop rotation
Tomato	Fusarium Wilt	Resistant cultivars
	Southern Blight	Crop rotation Deep burial of crop residue Apply soil fungicide as preplant treatment
	Early Blight	Apply fungicides as needed
	Septoria Leaf Spot	Crop rotation
	Anthracnose	Resistant cultivars Do not plant tomatoes following cabbage, lettuce, mustard and solanaceous weeds Apply fungicides as needed
	Stemphylium Leaf Spot	Apply fungicides as needed
	Late Blight	Apply fungicides as needed Use plastic mulch to prevent fruit from coming in contact with the soil Avoid heavy irrigations just prior to and during harvest
	Buckeye Rot	Three year crop rotation Plant on raised beds Avoid heavy applications of water just prior to and during harvest
	Tomato Spotted Wilt	Control thrips Rogue diseased plants Do not plant tomatoes near Irish potatoes
	Other Viruses	Resistant cultivars Control weeds in and around field

Chemical Application and Safety

Table IX-1. Summary of Sprayer Types

Type	Size	Tank Pressure	Speed	Cost	Use
Small Sprayers
Handheld	1 – 3 gal	variable1	variable2	$15 – $100	Spot, small acreage
Backpack	3 – 5 gal	variable	variable	$90 – $150	Spot, small acreage
Backpack	5 gal	constant3	variable	$400	Spot, small acreage
Backpack (mist blower)	2 – 3 gal	NA4	variable	$400 – $600	Spot, small-medium size acreage
Handheld controlled
Droplet sprayer	2 – 5 pt	NA	variable	$200 – $300	Spot, small acreage
Large Sprayer
Boom sprayer (tractor mounted)	25 – 300 gal	constant	constant	$200 – $2,000	Small-large acreage

Table IX-2. Nozzle height for flat fan nozzles

	Nozzle Height (inches)
Spray Angle	20″ Spacing	30″ Spacing
65	21 – 23	32 – 34
80	17 – 19	24 – 26
110	10 – 12	13 – 15

Table IX-3. Normal Hose Flow Rates

Hose Size in inches	3/8″	1/2″	5/8″	3/4″	1″	1 1/4″
Max. Flow (gpm)	2	4	8	12	20	40

Table IX-4. Materials Used in the Manufacture of Nozzles

Material	Corrosive	Abrasive	Cost
Brass	Mod. Resistant	Susceptible	Inexpensive
Nylon	Resistant	Susceptible	Inexpensive
Stainless Steel	Resistant	Resistant	Expensive
Hardened Tungsten	Resistant	Resistant	Very Expensive
Ceramic	Resistant	Resistant	Very Expensive

Table IX-5. Spray calibration distances for different tip spacing (a boom with 2 or more tips) or spray pattern widths (a single tip)

Nozzle Spacing (inches)	Calibration Distance (feet)
28	146
24	170
20	204
18	227
16	255
14	292
12	340
10	408

Table IX-6. Required Distance to Travel at Different Nozzle Spacing

Spacing (in)	Row Width or Nozzle Distance (ft)	Spacing (in)	Row Width or Nozzle Distance (ft)
40	102	26	157
38	107	24	170
36	113	22	185
34	120	20	204
32	127	18	227
30	136	16	255
28	146	14	291

Table IX-7. Conversion Table

1 tablespoon = 3 teaspoons = 0.5 ounces

1 oz. = 2 tablespoons

1 cup = 1/2 pint = 16 tablespoons = 8 ounces

1 pint = 2 cups = 32 tablespoons = 16 ounces = 1 lb.

1 gallon = 16 cups = 8 pints = 4 quarts = 8.4 pound of water

1 cu. feet = 7.48 gallons o= 62.4 pounds

1 acre = 43,560 sq. feet

1 mph = 88 feet/minute

Harvest and Handling

Table X-l. Cooling Methods for Vegetables

Method1	Vegetable	Comments
Room Cooling	All vegetables	Too slow for many perishable commodities. Cooling rates vary extensively within loads, pallets, and containers
Forced Air Cooling (Pressure Cooling)	Strawberry, Fruit-type Vegetables, Tubers, Cauliflower	Much faster than room cooling:, cooling rates very uniform. Container venting and stacking requirements are critical to effective cooling
Hydrocooling	Stems, Leafy Vegetables, Some Fruit-type Vegetables	Very fast cooling; uniform cooling in bulk if properly used, but may vary extensively in packed shipping containers; daily cleaning and sanitation measure essential; product must tolerate wetting; water tolerant shipping containers may be needed
Package Icing	Roots, Stems, Some Flower-type Vegetables, Green Onion, Brussels Sprouts	Fast cooling; limited to commodities that can tolerate water-ice contact; water tolerant shipping containers are essential
Transit Cooling Mechanical Refrigeration	All Vegetables
Top-Icing and Channel-Icing	Some Roots, Stems, Leafy Vegetables, Muskmelon	Cooling in most available equipment is too slow and variable; generally not effective. Slow and irregular, top-ice weight reduces net pay load; water-tolerant shipping containers needed

Table X-2. Effect of pH on Amount of Active Chlorine in Solution

pH	% Active Chlorine
6.5	90
7.0	73
7.2	66
7.6	45
8.0	21
8.5	10

Table X-3. Chilling Injury Symptoms¹

Product	Lowest Safe Temperature (°F)	Symptoms
Asparagus	32/36	Dull, gray green, limp tips
Bean, lima	34/40	Rusty brown specks, spots
Bean, snap	45	Pitting and russeting
Cucumber	45	Pitting, water soaked spots
Eggplant	45	Surface scald, Alternaria rot, blackening of seeds
Muskmelon	36/41	Pitting, surface decay
Honeydew	45/50	Reddish tan discoloration, pitting, surface decay, failure to ripen
Watermelon	40	Pitting, objectionable flavor
Pepper, Sweet	45	Sheet pitting, Alternaria rot on pods and calyxes darkening of seed
Potato	38	Browning, sweetening
Pumpkin and Winter Squash	50	Decay, especially Alternaria rot
Sweetpotato	55	Decay, pitting, internal discoloration, hard core when cooked
Tomato, mature green	55	Poor color when ripe, Alternaria rot
Tomato, ripe	45/50	Water soaking and softening, decay

¹ Stored at low but nonfreezing temperatures

Table X-4. Susceptibility of Fruits and Vegetables to Freezing Injury¹

Most Susceptible	Least Susceptible
Asparagus	Beet
Beans, snap	Brussels Sprouts
Cabbage	Turnip
Cucumber	Kale
Eggplant	Kohlrabi
Lettuce	Parsnips
Okra	Salsify
Peach
Pepper, sweet
Plum
Potato
Squash, Summer
Sweetpotato
Tomato

¹Most = injured by one light freezing
Least = lightly frozen several times without serious damage, but shelf life likely reduced