Posts Tagged ‘pepper anthracnose’

Vegetable Disease Updates – July 8, 2011

Friday, July 8th, 2011

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

Late Blight
There have been no new late blight detections in DE or VA on potatoes. The disease apparently is under control and the weather has not been very favorable, especially where the temperatures have been over 90°F. Besides the two finds in DE and VA the only active late blight at present appears to be on Long Island, NY on both potato and tomato.

Downy Mildew on Cucurbits
As most of you know by now downy mildew was found in Sussex County on Tuesday and Dorchester County, MD. Both finds were on pickling cucumber. Since then downy mildew was found in an additional field near Bridgeton, NJ, Talbot County, MD, Wyoming County, PA, and several more cucumber fields in NC. Now is the time to be spraying specific fungicides for downy mildew on cucumbers. Continue to check the IPM pipe website for more information on the spread of downy mildew: http://cdm.ipmpipe.org.

Root Knot Nematode
Root knot nematode can be a very yield limiting pathogen on very susceptible crops like cucumbers and other vine crops, lima beans, snap beans and tomatoes to name a few. They are often worse in very sandy soils or sandy knolls in fields. With the temperatures that we have seen here in DE you can begin to see the swellings or galls on the roots in about 21 days from seeding or transplanting. Plants in infested areas of the field will be stunted and if the plants are dug carefully, if root knot is present, you will see galls of varying sizes on the roots. We have no chemical controls except for vine crops once the nematodes are seen. Vydate should be applied preventatively in fields with known root knot infestations at seeding and/or later when plants are still small. See label for details. Treating early is always better than waiting until galls can be seen.

Root knot galls on baby lima bean roots, 23 days from planting

Pepper Anthracnose
Be on the lookout for anthracnose on peppers. It has been reported in southern NJ. Anthracnose fruit rot can be a very difficult disease to control if it gets established in a field. Fields should be scouted frequently especially if peppers or tomatoes have been planted in the past. It is best controlled by preventative fungicide sprays beginning at flowering. Apply Bravo or another chlorothalonil product every 7 days and alternate with a stroblilurin fungicide (FRAC code 11) like Cabrio or Quadris plus Bravo. If anthracnose fruit rot appears, removing infected fruit from heavily infected areas will help to reduce spore loads and reduce spread if done early and often enough. Fruit will need to be removed from the field and not just thrown on the ground.

Anthracnose on pepper fruit

 

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

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

Vegetable Crop Diseases

Thursday, July 3rd, 2008

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

Tomato Spotted Wilt Virus
Tomato spotted wilt virus was indentified and confirmed today by ELISA on tomato plants from across the line in MD. We don’t see this very often but the symptoms are pretty obvious most of the time. It can be a problem when tomato transplants are produced with ornamental bedding plants, which harbor the virus. The virus is often then transmitted to tomatoes by Western flower thrips. The virus can be transmitted from weeds and perennial ornamentals as well by nine species of thrips. Young leaves are bronze colored and later develop numerous small dark spots. Growing points may die and stems of terminals may be streaked.

 

Tomato spotted wilt on tomato

Bacterial Wilt in Cucurbits*
Symptoms of bacterial wilt will vary depending on the cucurbit crop. In general, plants may wilt during the day in hot weather and ‘recover’ during cooler parts of the evening and morning. Margins and interveinal areas of leaves become necrotic which cause leaves to appear ‘scorched’. Look for beetle feeding scars on cotyledons and stems of young plants. Healthy green plants will turn chlorotic (yellow) with time and infected plants will eventually collapse and die, exposing fruit to sunscald injury. Cutting through stem tissue at the base of infected plants often reveals a coppery-tan color where the bacterium causes the vascular tissue to ‘plug up’. Control of bacterial wilt begins with controlling striped and spotted cucumber beetles which vector the pathogen early in the growing season as plants emerge. Late-season beetle control will remain important as fruit begins to mature. Late-season beetle feeding may cause injury to stems ruining aesthetic quality. For more information on cucumber beetle and bacterial wilt control please see the 2008 Delaware Commercial Vegetable Production Recommendations Guide.

Anthracnose of Pepper
Symptoms of anthracnose infection in pepper 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 with using clean-free seed and/or transplants. A three-year crop rotation with non-solanaceous crops is recommended. After the harvest season, pepper fields should be disced and plowed under thoroughly to bury crop debris. 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 6.2 to 15.4 fl oz 2.08F/A)
or
Flint (trifloxystrobin) 50WDGat 2 to 4 oz/A
or
Cabrio (pyraclostrobin) 20EG at 8 to 12 oz/A
or
Tanos (famoxodone + cymoxanil, 11 + 27) at 8 to 20 50WDG/A.

 

Anthracnose on pepper fruit

Bacterial Leaf Spot of Pepper*
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. Loss 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 to 10 oz Tanos (famoxadone + cymoxanil, 11 + 27) may help suppress spread. For more information on control of Bacterial leaf spot of pepper please see the 2008 Delaware Commercial Vegetable Production Recommendations.

*From Andy Wyenandt, Rutgers University