Posts Tagged ‘pepper’

Grafted Vegetables

Thursday, May 12th, 2011

Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

Using grafted vegetables for field production is relatively new practice in the United States. However, it is a common practice in Asian countries as well as other areas of the world.

Grafting involves selecting a rootstock that will confer some desired trait, usually resistance to a soil-borne disease. A scion plant is selected, normally the crop and variety with the horticultural traits desired. The scion is grafted onto the rootstock. For example, with tomatoes, a seedling is severed just above the cotyledon. The above-ground portion (scion) of a desired variety for harvest is secured to the root system (rootstock) of the disease-resistant seedling. Once the grafted transplants heal, they can be planted in the field for normal production.

Vegetables that have been successfully grafted include tomatoes, peppers, and eggplants and watermelons, cantaloupes, cucumbers, and other cucurbits.

Grafting can be effective as a non-chemical control method for many soilborne diseases such as Verticillium wilt and Fusarium wilt in tomatoes, Fusarium wilt in watermelons, and root knot nematodes in tomatoes and cucurbits.

Grafting onto vigorous rootstocks can also allow plants to be more stress tolerant because the rootstock has a greater rooting area. This will allow for better water stress and heat tolerance.

Grafting can also improve overall productivity of crops when no disease or stress is present. Again, the vigorous root systems can improve overall nutrient and water uptake and increase fruit yields. In watermelons, rootstocks have been shown to improve fruit quality and holding ability in the field.

Much research is underway on grafted vegetables throughout the region and several growers have started to use grafted plants for production.

 

Pepper Phytophthora Blight Control Recommendations

Friday, May 6th, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

For control of the crown rot phase of phytophthora blight in pepper:
Apply 1.0 pt Ridomil Gold 4SL/A or 1.0 qt Ultra Flourish 2E/A (mefenoxam, 4), or MetaStar (metalaxyl, 4) at 4.0 to 8.0 pt 2E/A. Apply broadcast prior to planting or in a 12- to 16-inch band over the row before or after transplanting. Make two additional post planting directed applications with 1 pint Ridomil Gold SL or 1 qt Ultra Flourish 2E per acre to 6 to 10 inches of soil on either side of the plants at 30-day intervals. Use formula titled “Calibration for Changing from Broadcast to Band Application” from Calibrating Granular Application Equipment in Section E of the Delaware Commercial Vegetable Production Recommendations to determine the amount of Ridomil Gold needed per acre when band applications are made. When using polyethylene mulch, apply Ridomil Gold 4SL at the above rates and timing by injection through the trickle irrigation system. Dilute Ridomil Gold 4SL prior to injecting to prevent damage to injector pump. Do not use mefenaoxam or metalaxyl if insensitive strains of Phytophthora capsici are present.

 

Early Transplanting of Warm Season Vegetables

Thursday, April 14th, 2011

Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

Earliest plantings of watermelons, cantaloupes, summer squash, and tomatoes will begin in the next 10 days. First transplanting of crops such as peppers and eggplant will begin in early May. One of the characteristics that all of these crops have in common is that they are warm season vegetables that are sensitive to cold temperatures, both in the root zone and above ground. There has been a tendency to risk earlier and earlier plantings as growers try to hit the early market. Over the years, many of our early plantings of summer vegetables have suffered because of early cold damage and inadequate provisions to protect plants.

For early transplanted warm season vegetables choose the lightest ground that warms up quickly. Plant higher sections in the field first. Avoid areas that receive any shade from woods or hedgerows. Early fields should be protected from extreme wind and should not have frost pockets. Rye windbreaks planted between each bed are desirable for early plantings because they limit heat transfer by wind. If no rye windbreaks have been planted, then consideration should be given to using row covers to protect the plants – either clear slitted or perforated low tunnels or floating row covers. Even where windbreaks have been used, row covers may be necessary for extremely early plantings.

Lay plastic mulch well ahead of time to warm soil. Black plastic mulch should have excellent soil contact. Firm beds and tight mulch are much more effective in warming soils. Make sure that there is good soil moisture when forming beds and laying plastic because soil water will serve as the heat reservoir during cold nights.

When producing transplants, use larger cell sizes and grow plants so that they have well developed roots in those cells for the first plantings. Large cell sizes will perform better than small cells in early plantings. Careful attention needs to be paid to hardening off warm season vegetable transplants that will be planted early. Gradual acclimation to colder temperatures will reduce transplant shock. Do not transplant tender, leggy plants or plants coming directly out of warm greenhouse conditions for these early plantings.

Watch extended weather forecasts and plant at the beginning of a predicted warming trend. Monitor soil temperatures in plastic beds and do not plant if they are below 60°F. Soil temperature in beds should be measured at the beginning of the day when at the coolest. When soil temperature conditions are not favorable, wait to plant. Avoid planting in extended cloudy periods, especially if plants have come out of the greenhouse after an overcast period. These plants will not perform well. Extra caution should be taken to minimize root injury during transplanting. When transplanting, make sure that there is good root to soil contact and there are few air pockets around roots.

In years with cold, cloudy, windy weather after transplanting, we have had large losses of transplants in the field. It is critical to have warm soil conditions after transplanting to allow roots to grow out into the bed quickly. In cold, cloudy conditions, plants shut down physiologically, little root growth occurs, and the existing roots on the transplant do not function well. If there is any wind, plants lose more water than they can take up and they die due to desiccation. This is accelerated when the sun does come out – the first sunny day after an extended cold, cloudy period is when you will see the most wilting of weakened transplants.

If cold weather occurs after transplanting, warm season vegetables vary in their ability to tolerate adverse weather after being set out. Tomatoes will stop growth but will grow out without much damage once warm weather returns. Summer squash and cucumber transplants may be temporarily stunted but generally grow out of the condition. Watermelons will hold if they have been hardened off properly. Cantaloupes can be stunted if exposed to excessively harsh early conditions. Peppers and eggplants will not put on any root growth until temperatures are warm enough. If stunting occurs on any of these warm season vegetables, you may lose the early advantage you were seeking. In addition, remember that all of these vegetables are susceptible to frost damage and will be killed by a late freeze.

 

Pepper Anthracnose

Thursday, June 17th, 2010

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Symptoms of pepper anthracnose on fruit include sunken, circular spots which develop blackish-tan to orange concentric rings as lesions develop. Lesions on stems and leaves appear as grayish-brown spots with dark margins and can easily be overlooked. Control of anthracnose begins scouting on a regular basis and applying preventative fungicides before symptoms appear, especially in fields or areas of the farm where you have had anthracnose problems in the past. Beginning at flowering and as small fruit begin to set, alternate chlorothalonil (M5) at 1.5 pt 6F/A with one of the following FRAC code 11 fungicides: azoxystrobin (Quadris at 6.0 to 15.5 fl oz 2.08F/A) or Cabrio (pyraclostrobin) 20EG. After harvesting, pepper fields should be disced and plowed under thoroughly to bury crop debris.

 

Anthracnose on bell pepper fruit

Stem Girdling in Peppers

Friday, June 11th, 2010

It’s the time of year when we sometimes see pepper transplants with the symptoms pictured below.

 

This is sunscald injury on the stems of newly transplanted pepper seedlings, which is caused by stems laying against edges of black plastic mulch on hot, sunny days. Note that secondary pathogens such as Alternaria can infest bleached out areas of stems over time.

Transplant Shock

Thursday, May 13th, 2010

Gordon Johnson, Extension Fruit & Vegetable Specialist; gcjohn@udel.edu

The first seven days in May in 2010 saw temperatures in the high 80s and even some night temperatures in the low 70s in Delaware, and while windy, it was not excessively so. Then came the weekend of the 8th and 9th where average wind speeds doubled or tripled followed by low temperatures the middle of this week with scattered frost at night. These weather conditions illustrate the perils of setting out warm-season transplants in the beginning of May and to the need to take actions to avoid transplant shock.

Transplant shock will be evident by severe wilting, drying of leaves and stems, and, in severe cases, full plant collapse and death. This should not be confused with diseases such as Pythium damping off or damage from seed corn maggot or other soil insects.

Many of our transplants come from southern producers this time of year and there is always the potential for transplant shock when they are removed from southern greenhouses with little or no hardening and then are shipped up to Delaware in unheated trucks, especially when temperatures drop in the 40s or below during transport. Locally grown transplants are also susceptible to transplant shock if taken directly from greenhouses to the field without a hardening off process. Even with good hardening off, 40 mph winds can quickly desiccate plants if set in the field, especially without adequate windbreaks.

As a reminder, warm season vegetable transplants vary in their ability to withstand sub-optimal conditions depending on how well they have been hardened off and their inherent ability to withstand stress. Tomatoes, cucumbers, and squash are better able to handle early season stresses than cantaloupes, watermelons, or peppers.

Soil temperatures are a key factor in the establishment of warm season crops. It is important to lay plastic well ahead of planting and to have adequate soil moisture to absorb and then retain heat. When soil temperatures are too cold, root growth is minimal in these crops and root function is impaired. Water uptake is limited by low root activity and new growth and rooting-in is slowed. Root zone insects and diseases can further stress transplants and reduce stands in cold conditions.

To avoid transplant shock, make sure transplants have well developed root systems. Transplants should easily pull from trays and have full root balls. This is critical to avoid transplant shock. Do not rush transplants with poorly developed roots into the field. Make sure transplants have been hardened off well by exposing them to outside conditions, eliminating fertilizer, and controlling watering well ahead of planting. Leggy plants will be a problem in stressful conditions and should not be used if at all possible. Leggy plants are more susceptible to damage in transplanting and wind damage after planting thus subjecting them to additional stress.

It is important to plant so that soil covers the root ball and that the root ball is not exposed to drying. However, for crops such as watermelons and cantaloupes, make sure that soil does not surround the stem. Deep planting in cold wet soils will result in additional stress on melons. Extra care should be taken during transplanting during stressful periods to reduce injury to plants, particularly to root balls. Damage to roots will reduce establishment success especially in melons, cucumbers, and squash. Train planting crews so that they do minimal damage to transplants. If plants are not pulling well from trays and do not have intact root balls, plants will not survive adverse weather.

Avoid planting if weather conditions are unfavorable. Look at extended forecasts and plant on a warming trend where winds are not excessive. If heavy winds or very cold nights are expected, it is best to wait until more favorable weather returns. Often there is no earliness gained by planting in the stressful period; or gains are negated by stand losses and the need to replant areas. If weather conditions are unfavorable, you may also consider using row covers to protect plants.

Windbreaks are critical for early plantings. Use windbreaks between every bed for the early plantings and have windbreaks between multiple beds for later plantings. This year, many of our windbreaks offer minimal protection due to poor fall and winter growing conditions. Where windbreaks are not adequate, delay planting until favorable weather is in the forecast.

Update on Alternatives if Fall Windbreaks Were Not Established for Spring-Planted Vegetables

Thursday, March 4th, 2010

Gordon Johnson Extension Fruit & Vegetable Specialist; gcjohn@udel.edu

Due to the wet fall in 2009, many vegetable growers on Delmarva were not able to plant small grain windbreaks such as winter rye in fields slated for watermelons, cantaloupes, and other vegetable crops in spring of 2010. A special edition of the Weekly Crop Update was issued on January 25, 2010 (http://agdev.anr.udel.edu/weeklycropupdate/?p=1649) with some options for spring planted windbreaks.

Snow melt and continued wet weather has caused further delays for potential spring plantings. The following are some updated recommendations for spring windbreaks when the weather breaks (hopefully in the next 2 weeks).

Windbreaks most commonly are planted between groups of 3 or more beds to reduce wind damage and sandblasting on young crops. Some growers have windbreaks between every bed to help trap heat and provide additional protection on early transplanted crops.

By mid-March, winter rye, wheat, or barley are not good windbreak options because they will probably not vernalize and produce stems. They will remain vegetative or short.

March-planted alternatives for windbreaks are spring oats, annual ryegrass, and tall mustards.

Spring oats, planted as early as possible, is probably the best option for March plantings. Use a high seeding rate (120 pounds per acre or more). Oats will provide good ground cover and will head in late spring. It will start to elongate in mid-May. While still not an answer as a full windbreak for early plantings it will reduce sandblasting and provide protection for later plantings. Height will be over 3’ at heading

Annual ryegrass will also produce significant growth from a March planting and provide soil cover. Plant seeds at a rate of 30 pounds per acre. Annual ryegrass can get as high as 3’ when producing seed heads but provides less of a windbreak. One concern is with annual ryegrass is that if it goes to seed it has the potential to become a weed problem in the future.

There are several tall mustard varieties that merit considerations as windbreaks from March plantings. As these mustards produce a flower stalk, they can reach a height of over 4’. They are often used as biofumigant cover crops. Varieties of these tall mustards include ‘Idagold’, ‘Pacific Gold’,’ Caliente 119’, and ‘Caliente 99’. These mustards flower 50-60 days after planting and can be over 4’ in height. Plant at 10-15 pounds per acre.

Mixtures containing 2 or more of the crops mentioned above (spring oats, annual ryegrass, tall mustards) may be more desirable as a late winter or early spring planted windbreak. Reduce seeding rates of each component by 1/3 in mixtures.

The University of Delaware Vegetable Extension Program will be doing research on windbreak alternatives for late-winter or early-spring planting in 2010. We are seeking on-farm cooperators. If you are interested, contact information is given below:

Gordon C. Johnson
Extension Vegetable and Fruit Specialist
University of Delaware, Carvel Research and Education Center
16483 County Seat Highway
Georgetown, DE 19947
General Phone: (302) 856-7303
Direct Phone: (302) 856-2585 x 590
Cell Phone: (302) 545-2397, Fax: (302) 856-1845
Email: gcjohn@udel.edu

Wind Break Alternatives Planted in Late-Winter or Early-Spring for Spring Planted Vegetables

Wednesday, January 27th, 2010

January 25, 2010

Situation

Due to the wet fall in 2009, many vegetable growers on Delmarva were not able to plant small grain windbreaks such as winter rye in fields slated for watermelons, cantaloupes, and other vegetable crops in spring of 2010. 

Windbreaks most commonly are planted between groups of 3 or more beds to reduce wind damage and sandblasting on young crops.  Some growers have windbreaks between every bed to help trap heat and provide additional protection on early transplanted crops. Winter rye is the most common crop that is planted for windbreaks.  It is cold hardy, greens up early, and can reach a height of over 4 feet by late-April making it a good windbreak.   Winter wheat and barley have also been used but are later heading or are shorter.  Small grains are planted from late-September through early-November.  October plantings provide the best combination of tillering and winter cover without excessive fall growth.

In 2009, we had one of the wettest fall periods on record and many windbreaks were not planted.  Therefore, information on late winter or early spring planted alternatives is needed.  The following are questions and answers regarding late-winter or early-spring planted windbreaks (February-March) to help protect spring planted vegetable crops.

1)    Can winter rye, wheat, or barley still be planted in late-winter or early-spring as a windbreak? 

Yes, but there is a risk that it will not vernalize and produce stems and heads (may remain vegetative or short).

Winter-planted small grains such as winter rye and wheat will not produce stems and seed heads until after they have been exposed to cold temperatures. This exposure to cold temperatures, resulting in physiological changes in the plant, is called vernalization. The degree of vernalization required can vary by variety. Contrary to popular belief, the best vernalization temperatures are in the 40-50° F range, not at colder temperatures. For vernalization to occur, plants have to be biologically active (cool but above freezing).  Those plants that need vernalization require an additional environmental cue, change in day length, to ensure that flowering (heading) occurs in spring. The environmental cues of vernalization and day length change act together to promote spring flowering. Four to six weeks of 40-50°F temperatures are required for vernalization.

Past experience in Delaware has shown that winter wheat planted in late February or very early March will vernalize and be able to produce stems and heads.  Winter rye should also follow that pattern. It is critical to plant by March 1 to have the best chance of producing stems and not remain vegetative.  For these winter plantings, up your seeding rate to 150 pounds per acre.  Rye planted in February will be several weeks later to head and still may not provide full windbreak protection to April plantings.  Winter wheat, particularly southern bred varieties, may be more successful, especially moving into early March. 

2)    Are there other alternatives for March planted windbreaks?

Yes, spring oats, annual ryegrass and tall mustards are alternatives. 

As you go further into March, the chance of success with winter rye or wheat is reduced (it may remain vegetative with limited height).  The following is more information on alternatives to consider:

Spring Oats

Spring oats, planted as early as possible, is probably the best option for March plantings.  Use a high seeding rate (120 pounds per acre or more).  Oats will provide good ground cover and will head in late spring.  It will start to elongate in mid-May.  While still not an answer as a full windbreak for early plantings it will reduce sandblasting and provide protection for later plantings.  Height will be over 3’ at heading

Annual Ryegrass

Annual ryegrass will also produce significant growth from a March planting and provide soil cover.  Plant seeds at a rate of 30 pounds per acre.  Annual ryegrass can get as high as 3’ when producing seed heads but provides less of a windbreak.  One concern is with annual ryegrass is that if it goes to seed it has the potential to become a weed problem in the future.

Tall Mustards

There are several tall mustard varieties that merit considerations as windbreaks from March plantings.  These are “Idagold” mustard and “Pacific Gold” mustard.  As these mustards produce a flower stalk, they can reach a height of over 4’.  They are often used as biofumigant cover crops.  “Idagold” will reach full height and flower 55 days after planting and could possibly provide an April windbreak.  “Pacific Gold” also flowers at 55 days after planting and can also be over 4’ in height.  Plant at 10 pounds per acre.

Mixtures

Mixtures containing 2 or more of the crops mentioned above (spring oats, annual ryegrass, tall mustards) may be more desirable as a late winter or early spring planted windbreak.  Reduce seeding rates of each component by 1/3 in mixtures.

The University of Delaware Vegetable Extension Program will be doing research on windbreak alternatives for late-winter or early-spring planting in 2010.  We are seeking on-farm cooperators.  If you are interested, contact information is given below.

Gordon C. Johnson
Extension Vegetable and Fruit Specialist,

University of Delaware, Carvel Research and Education Center
16483 County Seat Highway, Georgetown, DE 19947
General Phone: (302) 856-7303, Direct Phone: (302) 856-2585 x 590, Cell Phone: (302) 545-2397, Fax: (302) 856-1845
Email: gcjohn@udel.edu

Pepper Disease Control

Friday, June 26th, 2009

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Delaware does not have the acres of peppers we once had but it is still an important crop. The following are several disease control suggestions from Andy Wyenandt from Rutgers University that are timely.

Bacterial leaf spot
Bacterial leaf spot has been found. Symptoms of bacterial spot on pepper leaves include small, brown water-soaked lesions that turn brown and necrotic in the centers. Spots may coalesce and form large blighted areas on leaves and premature defoliation can occur. On fruit, brown lesions can form which have a roughened, cracked, wart-like appearance. High temperatures, high relative humidity and rainfall favor bacterial spot development. Losses from bacterial spot can be reduced somewhat by maintaining high levels of fertility, which will stimulate new growth. Applying a fixed copper (M1) at labeled rates plus maneb (M3) at 1.5 lbs 75DF/A or 8.0 to 10.0 oz Tanos (famaxodone + cymoxanil, 11 + 27) may help suppress spread. For more information on control of bacterial leaf spot of pepper please see the Delaware Commercial Vegetable Production Recommendations.

Phytophthora Blight on Pepper
For control of the crown rot phase of blight, broadcast prior to planting or in a 12 to 16-inch band over the row before or after transplanting:
1.0 pt Ridomil Gold 4E/A,
or
1.0 qt Ultra Flourish 2E/A (mefenoxam, 4),
or
MetaStar (metalaxyl, 4) at 4.0 to 8.0 pt 2E/A.

Make two additional post planting directed applications with 1 pint Ridomil Gold 4E or 1 qt Ultra Flourish 2E per acre to 6 to 10 inches of soil on either side of the plants at 30-day intervals. Use the formula “Calibration for Changing from Broadcast to Band Application” on page E6 in the Pest Management Section of the Delaware Commercial Vegetable Production Recommendations to determine amount of Ridomil Gold needed per acre when band applications are made.  When using polyethylene mulch, apply Ridomil Gold 4E at the above rates and timing by injection through the trickle irrigation system. Dilute Ridomil Gold 4E prior to injecting to prevent damage to injector pump.

Anthracnose on Pepper
Symptoms of fruit infection include sunken, circular spots which develop blackish-tan to orange concentric rings as lesions develop. Lesions on stems and leaves appear as grayish brown spots with dark margins and can easily be overlooked. Control of anthracnose begins with scouting on a regular basis and applying preventative fungicide applications before symptoms appear, especially in fields or areas of your farm where you have had anthracnose problems in the past. Beginning at flowering and as small fruit begin to set, alternate maneb (M3) at 1.5 to 3 lb/A 75DF with one of the following FRAC code 11 fungicides:
azoxystrobin (Quadris at 6.0 to 15.5 fl oz 2.08F/A),
or
Flint (trifloxystrobin) 50WDG at 3.0 to 4.0 oz/A,
or
Cabrio (pyraclostrobin) 20EG at 8.0 to 12.0 oz/A,
or
Tanos (famaxodone + cymoxanil, 11 + 27) at 8 to 10 50WDG/A.

After harvesting, pepper fields should be disked and plowed under thoroughly to bury crop debris.

pepperanthracnoseAnthracnose on pepper fruit

Controlling the Crown Rot Phase of Pepper Phytophthora Blight

Friday, May 22nd, 2009

Andy Wyenandt, Assistant Extension Specialist in Vegetable Pathology, Rutgers University; wyenandt@aesop.rutgers.edu

To control the crown rot phase of Phytophthora blight in pepper apply 1.0 pt Ridomil Gold 4E/A or 1.0 qt Ultra Flourish 2E/A (mefenoxam, 4), or MetaStar metalaxyl, (4) at 4.0 to 8.0 pt 2E/A. Apply broadcast prior to planting or in a 12-16 inch band over the row before or after transplanting. Make two additional post planting directed applications with 1 pint/A Ridomil Gold 4E or 1 qt/A Ultra Flourish 2E to 6 to 10 inches of soil on either side of the plants at 30-day intervals. Use the formula “Calibration for Changing from Broadcast to Band Application” on page E6 in the Pest Management Section of the Delaware Commercial Vegetable Production Recommendations to determine amount of Ridomil Gold needed per acre when band applications are made. When using polyethylene mulch, apply Ridomil Gold 4E at the above rates and timing by injection through the trickle irrigation system. Dilute Ridomil Gold 4E prior to injecting to prevent damage to the injector pump.