Crop Profile for Blueberries (Highbush) in New England

Prepared: October, 2006

Information in this crop profile was collected by a survey distributed to New England growers in the fall of 2003. A Dillman survey methodology was used to design and conduct the survey. Most percent values in this document have been rounded for ease of reporting.

Survey Timeline

Summary of Survey Returns
(December 2003)

Basic Commodity Information

Production Statistics

New England is considered the northern edge of the climatic zone in which highbush blueberries can be grown. As a result, a number of disease problems associated with cold stress are more common here than in other blueberry growing areas. Average plant density is 863 plants per acre.

The ideal blueberry soil is a well-drained, yet moist sandy loam soil with a pH of 4.5 to 5.2. The blueberry has fine, fibrous roots near the soil surface that lack root hairs, so the root system has a relatively low absorptive capacity. Blueberry roots are unable to penetrate compacted soils and have limited tolerance to excessively wet or dry soils.

The shallow root system is sensitive to both high and low temperature extremes. A permanent organic mulch layer (wood chips, bark, sawdust, pine needles) 3 to 4 inches thick is required to protect roots from high temperature injury in the summer and cold temperature injury in the winter and to reduce moisture stress.

Notes on timing, importance, and worker exposure to pesticide residue.

REI = Reentry interval

Pruning

99% of respondents reported this activity

• Used to maintain a balance between vegetative growth and fruit production that allows for adequate penetration of sunlight, chemical treatments, and air flow.
• Pruning involves extensive contact with foliage. Wearing protective clothing can be problematic in summer heat, and heat stroke risk poses more immediate and severe health concerns than pesticide exposure.
• While there is usually some flexibility for timing pesticide sprays, prolonged REIs create scheduling problems for pruning, which must be completed within a certain time window.

Mowing, Cultivation, and Mulching

• These methods are used to suppress weeds, conserve soil water and nutrients, reduce humidity to discourage fungal diseases, maintain ground conditions for conducting pruning and harvest operations efficiently, and discourage voles and other pests.
• Mulching also is required to protect roots from high temperature injury in summer and cold temperature injury in winter. Mulch is applied or maintained one to two times per year, depending on the need.
• Cultivation and mowing are done four to six times per growing season depending on the need.
• All methods involve very little contact with treated bark and foliage. There is potential for operators to brush against foliage. Pesticide exposure is minimal.

Irrigation

• Irrigation is becoming increasingly important in new plantings for maximizing early growth and returns. The need for irrigation is not always predictable.
• Irrigation may begin early in the growing season and can extend into September.
• While there is usually some flexibility for timing summer pesticide sprays, prolonged REIs create scheduling and maintenance problems, making it more difficult to get this important work done.

Fertilization

• Leaf tissue analysis and soil sampling are used to determine fertilizer needs once per year or every one to three years.

• Fertilizer is generally applied in a split application of nitrogen. The first is applied at bloom and the second is applied one month later.

• Fertilizing involves very little contact with treated bark and foliage. There is potential for operators to brush against foliage. Pesticide exposure is minimal.

Chemical Application and Worker Protection

• Chemical pesticides are applied by means of backpack sprayer and tractor-mounted mist or boom spray equipment. Weed chemicals are applied in bands or as spot treatments. Workers are trained on proper handling and wear personal protective gear when applying pesticides. Chemicals are stored according to federal and state regulations.

Field activities that may occur during

Budbreak through Bloom:

Post-bloom through Harvest:

Post-harvest through Dormancy:

Pest Management Overview

• 84% of respondents reported spraying for diseases and viruses an average of 2 times per year.
• 90% of respondents reported spraying for insects an average of 1.7 times per year.
• 86% of respondents reported spraying for weeds an average of 1.2 times per year.
• 70% of respondents reported spraying for mites an average of 0.2 times per year.

Group A – Insect and mite pests identified by survey as most important

Notes for all following pesticide tables: Some survey respondents reported occurrence of a pest but did not give a rating for frequency. Thus the percentage of respondents reporting occurrence may be greater than the sum of percentages for different frequency ratings. More than one material may be used during a growing season, or not all growers may treat for a pest; thus, the percentage of respondents reporting use of listed materials may not add up to 100%. Only those pesticides listed by growers in the survey are included in these tables.

Blueberry Maggot

Type of Pest: Insect

Frequency of Occurrence: 83% of respondents reported this pest occurring.

Damage Caused: Maggots feeding within developing fruits renders fruit unmarketable. Berries become soft and mushy. Undetected infested berries contaminate pack-out.

% Acres Affected: 5%

Timing of Control: Apply protective insecticide when berries begin to turn blue or when flies begin to lay eggs, usually late June. Maintain protection until harvest.

Yield Losses: 30% without management, 5% with management
Regional Differences: None identified
Cultural Control Practices: In small plantings, it may be possible to trap this insect out with sufficient trap density.

*Written-in information from survey

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Chemical Controls for Blueberry Maggot

48% of crop reported treated for this pest in 2002.

*First cover = about 10 days after petal fall; some berries begin to color

**2^nd+ cover = 10 days from previous cover, repeat as needed

***Written-in information from survey

Cranberry Fruitworm

Type of Pest: Insect

Frequency of Occurrence: 71% of respondents reported this pest occurring.

Damage Caused: Found within developing and ripening berries. Feeding reduces the crop and spoils marketability of the berries.

% Acres Affected:  3%

Timing of Control: When damage is severe, treat in the following year with insecticide.

Yield Losses: 20%
Regional Differences: None identified
Cultural Control Practices: Effectively controlled by picking off infested berries, which are easily detected because of the webbing and their early ripening. This method is still practical in small plantations with light infestations. Elimination of weeds and dead plant material around blueberry plants cuts down on overwintering protection for cocoons.

*Written-in information from survey

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Chemical Controls for Cranberry Fruitworm

35% of crop reported treated for this pest in 2002.

*First cover = 7-12 days after petal fall

**Written-in information from survey

Group B – Insect and mite pests identified by survey as significant problems in some years

Blueberry Tip Borer

Type of Pest: Insect

Frequency of Occurrence: 72% of respondents reported this pest occurring.

Damage Caused: In June, before new growth has begun to harden, infested shoots may begin to wilt, arch over, and become discolored, the leaves turning yellowish with red veins and the stems purplish. This injury results in the destruction of the stem’s fruit-production potential in the following year.

% Acres Affected:  0%

Timing of Control: The standard spray program used for other insect pests normally

keeps this pest under control.

Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Prune out damaged tips as observed and burn infected canes.

*Written-in information from survey

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Chemical Controls for Blueberry Tip Borer

22% of crop reported treated for this pest in 2002.

Scale Insects

Type of Pest: Insect

Frequency of Occurrence: 69% of respondents reported this pest occurring.

Damage Caused: Infestations can result in reduced vigor and yield of bushes by feeding on the plant’s sap.

% Acres Affected:  10%

Timing of Control: During dormancy or delayed dormancy, apply superior-type oil. Treat from March 1 to first bloom.

Yield Losses: 3%
Regional Differences: None identified
Cultural Control Practices: Good pruning is the first step in control of scales on blueberries. Prune out weakened canes.

*Written-in information from survey

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Chemical Controls for Scale Insects

8% of crop reported treated for this pest in 2002.

Plum Curculio

Type of Pest: Insect

Frequency of Occurrence: 67% of respondents reported this pest occurring.

Damage Caused: Found on developing flower buds and later on developing berries. The larva bores into the fruit and eats its contents. As a result, a prematurely ripened fruit drops off the bush. This feeding activity on buds and fruit reduces yield.

% Acres Affected:  10%

Timing of Control: Spray applications made at petal fall to control cranberry or cherry fruitworm are also likely to control Plum Curculio.

Yield Losses: 3%
Regional Differences: None identified
Cultural Control Practices: None identified

*Written-in information from survey

Biological Control Practices: Plum curculio are more abundant where blueberries are located near tree fruit. If possible, plant blueberries away from tree fruit.

Postharvest Control Practices: None identified

Chemical Controls for Plum Curculio

17% of crop reported treated for this pest in 2002.

*Written-in information from survey

Cherry Fruitworm

Type of Pest: Insect

Frequency of Occurrence: 64% of respondents reported this pest occurring.

Damage Caused:

% Acres Affected:  

Timing of Control: When damage is severe, treat in the following year with insecticide. Apply when newly hatched larvae (1st or 2nd instar) begin feeding.

Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Disking between rows and raking and hoeing under plants is helpful for management. In small plantings remove and destroy infested fruit, which turns prematurely blue

*Written-in information from survey

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Chemical Controls for Cherry Fruitworm

27% of crop reported treated for this pest in 2002.

*First cover = 7-12 days after petal fall

**Written-in information from survey

White Grubs

Type of Pest: Insect

Frequency of Occurrence: 67% of respondents reported this pest occurring.

Damage Caused: The grubs consume feeder roots and may also girdle or clip off larger roots. The reduced root system cannot provide enough water to the plant. Damaged bushes show low vigor and reduced production. Adults, especially the Japanese beetle and rose chafer, sometimes become serious pests by consuming leaves, scarring the berries, and contaminating the harvest.

% Acres Affected:  5%

Timing of Control:

Yield Losses: 5%
Regional Differences: None identified
Cultural Control Practices: Growers should check new sites for white grubs before establishing a field, and take actions against grubs before planting. Remove webbed twigs and webworm caterpillars. Remove beetles.

*Written-in information from survey

Biological Control Practices: There is great interest in the use of pathogenic nematodes as biological control agents for the grubs.

Postharvest Control Practices: None identified

Chemical Controls for White Grubs

26% of crop reported treated for this pest in 2002.

*2^nd+ cover = 10 days from previous cover, repeat as needed

**Written-in information from survey

Group C – Insect and mite pests identified by survey as infrequent problems

Aphids

Type of Pest: Insect

Frequency of Occurrence: 68% of respondents reported this pest occurring.

Damage Caused: Virus vectors

% Acres Affected:  5%

Timing of Control:  NA

Yield Losses: 3%
Regional Differences: None identified
Cultural Control Practices: None identified

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Blueberry Bud Mite

Type of Pest: Mite

Frequency of Occurrence: 64% of respondents reported this pest occurring.

Damage Caused: Bud mites feed on the surface of the bud tissues and bud scales. Injured buds desiccate and usually produce distorted flowers. These flowers may fail to set fruit, or develop into fruit with rough skins.

% Acres Affected:  

Timing of Control: Plants should be inspected for bud mites in September, before the new buds are well formed. Apply immediately after harvest is complete and repeat according to label instructions.

Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Pruning of infested canes provides good control of bud mites.

Biological Control Practices: None identified

Postharvest Control Practices: None identified

Chemical Controls for Blueberry Bud Mite

1% of crop reported treated for this pest in 2002

*Written-in information from survey

Other

Mites: 4% of respondents reported this pest occurring.

Japanese Beetles: 15% of respondents reported this pest occurring.

Wasps: 2% of respondents reported this pest occurring.

Gypsy Moths: 2% of respondents reported this pest occurring.

Canker Worms: <1% of respondents reported this pest occurring.

White Moths: <1% of respondents reported this pest occurring.

Group A – Diseases identified by survey as most important

Mummy Berry

Type of Pest: Fungus
Frequency of Occurrence: 80% of respondents reported this pest occurring.

Damage Caused: Attacks new growth, foliage and fruit. Spores infect young tissue and cause rapid wilting. Developing fruit becomes malformed and turns salmon or grey by midsummer. By fall, these fruit have dropped to the ground where they turn to mummies.

% Acres Affected: 20%
Timing of Control:
Yield Losses: 30% without management, 5% with management
Regional Differences: None identified
Cultural Control Practices: Mummies can be raked up and burned or buried by cultivating between rows or by covering with a new layer of mulch at least 2" in thickness. The cultivation should be done just as apothecia start to emerge in the spring, which usually coincides with bud-break in the blueberry bushes. Cultivars exhibiting resistance to the shoot blighting phase of the disease include Jersey, Elliott, Bluejay, Duke, Stanley and Darrow.

*Written-in information from survey

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Mummy Berry

56% of crop reported treated for this pest in 2002.

ns=not specified

*Written-in information from survey

Phomopsis Twig Blight

Type of Pest: Fungus
Frequency of Occurrence: 68% of respondents reported this pest occurring.

Damage Caused: Infects blueberry stems causing dieback and plant decline. Younger tissue may show no symptoms at first, then exhibit rapid wilting and dieback. Lesions may appear on the stems. Leaf spots have also been observed where disease is particularly severe. The disease will cause premature ripening of the berries.

% Acres Affected: 20%
Timing of Control:
Yield Losses: 5%
Regional Differences: None identified
Cultural Control Practices: Since mechanical damage and cold stress seem to be necessary for infection, avoid careless pruning and cultivating, and do not fertilize late in the summer. Keep the plants well-watered through prolonged periods of dry weather. Avoiding any stresses will help prevent this disease. Cultivars which appear to be more resistant include Bluejay, Jersey, Duke, Pioneer, Darrow, Elliott, Stanley, Bluetta, Wareham, Rubel, Cabot, Rancocas and Pemberton. Prune out affected canes.

*Written-in information from survey

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Phomopsis Twig Blight

26% of crop reported treated for this pest in 2002.

ns=not specified

*Written-in information from survey

Anthracnose

Type of Pest: Fungus
Frequency of Occurrence: The disease is especially prevalent during hot muggy weather and frequently occurs post-harvest. Occurs only sporadically and especially during seasons with frequent rain and warm temperatures.

70% of respondents reported this pest occurring.

Damage Caused: Primarily damages fruit but may also infect twigs and spurs. Blossoms, mature fruit and succulent tissue are infected. Blossom clusters will turn brown or black. Stem cankers are rare. Young girdled stems die back, resulting in a brown withering of the leaves. Salmon or rust colored berry rot can ruin fruit quality. Infested fruit often exhibit a soft, sunken area. Spores spread to “good” fruit during and after harvest, causing significant post-harvest losses.

% Acres Affected: 5%
Timing of Control:
Yield Losses: 3%
Regional Differences: None identified
Cultural Control Practices: Pruning old canes and small twiggy wood for optimal air circulation and harvesting frequently are beneficial. Varieties in which the fruit hangs ripe for a long time on the bush prior to picking are especially susceptible. No varieties may be resistant when the weather conditions are favorable for the disease.

*Written-in information from survey

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Anthracnose

41% of crop reported treated for this pest in 2002.

ns=not specified

*First cover = about 10 days after petal fall; some berries begin to color

**2^nd+ cover = 10 days from previous cover, repeat as needed

*Written-in information from survey

Botrytis Blight

Type of Pest: Fungus
Frequency of Occurrence: It is present every year, but only causes severe damage during cool, wet periods several days in duration.

68% of respondents reported this pest occurring.

Damage Caused: Primarily affects blossoms and ripening fruit, although under certain circumstances the fungus can cause stem blight as well. Rotted berries typically have a gray cast of the mycelium and spore-bearing structures present.

% Acres Affected: 30%
Timing of Control: Infection occurs largely during bloom on flowers. The most critical period for infection is during bloom.
Yield Losses: 3%
Regional Differences: None identified
Cultural Control Practices: Disease is most severe where excessive nitrogen has been used, where air circulation is poor, or where frost has injured blossoms. Varieties possessing tight fruit clusters are particularly susceptible to the disease.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Botrytis Blight

35% of crop reported treated for this pest in 2002.

ns=not specified

*Written-in information from survey

Fusicoccum Canker

Type of Pest: Fungus
Frequency of Occurrence: 65% of respondents reported this pest occurring.

Damage Caused: Infects blueberry stems causing dieback and plant decline. On young (1-2 year old) stems, extensive stem infections quickly lead to flagging and dieback of the entire stem. On warm, dry days shoots will suddenly wilt and die due to the stem girdling.

% Acres Affected: 20%
Timing of Control: Spores are released from March to mid-July, and infection probably occurs during this period. New infections occur following rains during the time tender new tissue is present and temperatures are at 50-72½ F. New infections can occur throughout the growing season.
Yield Losses: 5%
Regional Differences: None identified
Cultural Control Practices: Sanitation is essential. Prune out affected canes. Varieties differ in their resistance to this disease. Avoid practices such as late season fertilization that make bushes more vulnerable to winter injury. Winter-injured bushes are more susceptible. Cold stress may play a part in increasing disease damage.

*Written-in information from survey

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Fusicoccum Canker

25% of crop reported treated for this pest in 2002.

ns=not specified

*Written-in information from survey

Group B – Diseases identified by survey as significant problems in some years

Witches’ Broom

Type of Pest: Fungus
Frequency of Occurrence: 68% of respondents reported this pest occurring.

Damage Caused: Diseased blueberry plants have broom-like masses of swollen, spongy shoots with shortened internodes and leaves reduced in size. Heavily infected plants produce no fruit.

% Acres Affected: 3%
Timing of Control:  Plant removal after harvest.
Yield Losses: 10%
Regional Differences: None identified
Cultural Control Practices: The best control strategy is to eradicate the alternate host (fir trees) within 1200 feet of the blueberry plants. Eradication of diseased blueberry plants effectively eliminates the disease from an affected field.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Witches’ Broom

Chemical controls do not exist.

Blueberry Stunt

Type of Pest: Mycoplasma-like organism
Frequency of Occurrence: 65% of respondents reported this pest occurring.

Damage Caused: Affected plants are dwarfed with shortened internodes, excessively branched, low in vigor with small downward cupped leaves which turn red prematurely. Fruits on infected bushes are small, hard, lack flavor, ripen late if at all, and remain attached to the plant much longer than they would on healthy plants.

% Acres Affected: Unknown
Timing of Control:  NA
Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Diseased bushes cannot be cured and must be removed from the field. Using virus indexed plants is also helpful.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Blueberry Stunt

Chemical controls do not exist.

Group C – Diseases identified by survey as infrequent problems

Phytophthora Root Rot

Type of Pest: Fungus
Frequency of Occurrence: 64% of respondents reported this pest occurring.

Damage Caused: In severely infected bushes, the entire root system is reduced in stature and is totally black. Above-ground symptoms include chlorosis and reddening of the leaves, smaller leaves, defoliation, branch dieback, death of entire canes, stunting, and death of the entire bush.

% Acres Affected: 5%
Timing of Control: Apply in spring before growth begins in established plantings. In new plantings, apply at or just after planting.
Yield Losses: 20%
Regional Differences: None identified
Cultural Control Practices: The disease is avoided through careful site selection before planting. Heavy soil which becomes waterlogged or suffers from a high water table should be avoided when selecting a site. Internal and surface water drainage should be improved. Most varieties are susceptible to the disease, although some varieties may better tolerate heavy infections.

*Written-in information from survey

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Phytophthora Root Rot

3% of crop reported treated for this pest in 2002.

Powdery Mildew

Type of Pest: Fungus
Frequency of Occurrence: 64% of respondents reported this pest occurring.

Damage Caused: When severe infection occurs, defoliation may occur.

% Acres Affected: 1%
Timing of Control: 
Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Some cultivars are more resistant than other cultivars.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Powdery Mildew

1% of crop reported treated for this pest in 2002.

*Written-in information from survey

Mosaic

Type of Pest: Virus
Frequency of Occurrence: 61% of respondents reported this pest occurring.

Damage Caused: Infected plants become unproductive. It may take several years for a bush to show symptoms.

% Acres Affected: Unknown
Timing of Control: NA

Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Most varieties appear to have field resistance to the virus. Infected bushes cannot be cured and must be removed promptly.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Mosaic

Chemical controls do not exist.

Red Ringspot

Type of Pest: Virus
Frequency of Occurrence: 60% of respondents reported this pest occurring.

Damage Caused: Production of the bush is seriously reduced and the berries become pockmarked and unattractive.

% Acres Affected: Unknown
Timing of Control: NA
Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Bluecrop, Collins, Jersey, Rancocas and Weymouth are resistant or tolerant to the disease. Infected bushes must be rogued out.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Red Ringspot

Chemical controls do not exist.

Blueberry Scorch

Type of Pest: Virus
Frequency of Occurrence: 61% of respondents reported this pest occurring.

Damage Caused: The disease is characterized by dieback of blossoms and young vegetative shoots in the spring, followed by a flush of growth in the summer. The roots suffer injury and production of the bushes can be greatly impacted.

% Acres Affected: 1%
Timing of Control: NA
Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: The sole control strategy is to remove affected bushes.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Blueberry Scorch

Chemical controls do not exist.

Blueberry Shoestring Disease

Type of Pest: Virus
Frequency of Occurrence: 61% of respondents reported this pest occurring.

Damage Caused: Diseased leaves are narrow, wavy, and somewhat sickle-shaped. Flowers may be red-streaked, and berries turn purple prematurely. Within a few years, berry production drops dramatically.

% Acres Affected: 1%
Timing of Control: NA

Yield Losses: Unknown
Regional Differences: None identified
Cultural Control Practices: Prevent disease introduction by buying disease-free plants, destroying wild plants near the planting, and removing diseased plants.

Biological Control Practices: None identified
Postharvest Control Practices: None identified

Chemical Controls for Blueberry Shoestring Disease

Chemical controls do not exist.

Crown Gall

Type of Pest: Bacteria
Frequency of Occurrence: Since blueberries are grown on acid soils, and the crown gall bacterium does not grow well in an acid situation, the disease occurs infrequently.

62%