Posts Tagged ‘pepper bacterial leaf spot’

Seed Treatment and New Selected Fungicides and Bactericides Labeled for Greenhouse Use Tables in 2010 Recommendations Guide

Thursday, April 1st, 2010

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

All seed used in transplant production as well as any transplants brought into the greenhouse should be certified “clean” or disease-free. Important diseases such as bacterial leaf spot of pepper and tomato can cause major problems in transplant production if introduced into the greenhouse. Bacterial leaf spot of pepper and tomato can be seed-borne and infested seed can be a major source of inoculums in the greenhouse and cause problems in the field later in the growing season. As a rule for any crop, any non-certified or untreated seed should be treated, if applicable, with a Clorox treatment, or hot water seed treatment, or dusted to help minimize bacterial or damping-off diseases. For more information on seed treatments for specific crops please see Table E-13 on page E46 in Section E of the 2010 Delaware Commercial Vegetable Production Guide.

An updated table for selected fungicides and bactericides labeled for greenhouse use is available in Section E of the 2010 recommendations guide. The table includes a comprehensive list of fungicides and biological agents approved for greenhouse use. Table E-14 can be found on pages E47-48 of the 2010 Delaware Commercial Vegetable Production Guide.

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