- Basil
- Pepper
- Potato
- Tomato
Basil
Downy mildew – has been reported for the first time this season near Vineland, NJ. Basil infections can originate from infested seed or from southern weather patterns. No cucurbit downy mildew has been reported in our region to date (in recent years based on observations, both pathogens tend to appear around the same time) so source of infection may be most likely through seed. All basil growers should scout their fields on a regular basis. All sweet basils are susceptible to the disease. Lemon/Lime and Spice-type basils appear to be tolerant/resistant. Control of basil downy mildew begins with planting resistant-types (when possible) and preventative fungicide applications BEFORE basil downy mildew appears on your farm. Weekly applications of a phosphite fungicide (FRAC code 33) such as K-Phite, Pro-Phyt, Rampart or other labeled phosphite at a high rate will help suppress basil downy mildew development. Ranman (cyazofamid, 21) at 2.75 to 3.0 fl. oz 400SC/A now has a federal label and will also help to suppress basil downy mildew development. Our research has shown that if fungicide applications are started AFTER the pathogen has been found in the field will result in very poor season-long control. For organic basil producers, unfortunately, all organic fungicides we have evaluated over the past three years have failed to provide any meaningful control of basil downy mildew. For more information, please see “Controlling basil downy mildew” from May 13, 2013.
Pepper
Bacterial leaf spot – Symptoms of bacterial leaf 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 or may help suppress spread. Quintec (quinoxyfen, 13) at 6.0 fl. oz/A is now labeled for the suppression of bacterial leaf spot in pepper in the mid-Atlantic region. Please see the 2013 New Jersey Commercial Vegetable Production Recommendations Guide for more information.
Phytophthora blight – Plant loss can be severe in all pepper types. Phytophthora blight typically develops in low-lying areas of fields after a heavy rain and can spread quickly throughout the entire field. Planting on a ridge or raised, dome-shaped bed will help provide better soil drainage. Use a minimum 3-year crop rotation with crops other than peppers, cucurbits, lima and snap beans, eggplants, or tomatoes. In fields with low-lying or wet areas, plant only Phytophthora-tolerant cultivars such as ‘Paladin’, ‘Aristotle’, ‘1819’, or ‘Revolution’. In heavily-infested fields with a known history of Phytophthora blight, plant only tolerant cultivars to help reduce plant losses. If mefenoxam-insensitivity is known to exist in a field/farm, plant only tolerant cultivars. Do not apply mefenoxam or metalaxyl in fields where insensitivity is known to exist.
For control of the crown rot phase of Phytophthora blight, apply:
mefenoxam–1.0 pt Ridomil Gold 4SL/A or 1.0 qt Ultra Flourish 2E/A or metalaxyl (MetaStar)–4.0-8.0 pt 2E/A at transplanting and 30 days later or,Presidio (fluopicolide, 43) at 3.0-4.0 fl. oz 4SC/A when conditions favor disease development, orRanman (cyazofamid, 21) at 2.75 fl oz 400SC (Ranman may be added to transplant water, see label for restrictions).
Phosphite materials (FRAC code 33) such as Rampart, ProPhyt, K-Khite may also be applied with one of the above to help suppress Phytophthora blight.
Potato
Black Leg – Black leg is caused by Erwinia spp. which also cause ‘soft rots’. The bacteria which lead to the aerial phase of Blackleg are soil-borne (originate from old crop debris) and spread by rainfall, overhead irrigation and wind. The aerial phase of Blackleg does not originate from decaying seed pieces. The bacterium can enter the plant through wounds created by cultivation or through stems damaged by blowing wind, sand or hail. Dense canopies, warm weather and prolonged periods of leaf wetness favor the spread of aerial Blackleg. Fortunately, the disease rarely extends below ground and only causes dieback of stems over time. Symptoms of the aerial phase of Blackleg first appear as an irregular, water-soaked ‘green’ decay on stems that turns light-brown to black over time. Hot, dry weather will cause infected areas to dry out and become brittle. Do any cultivating when plants are dry, cultivating in the presence of dew or wet plants may help to spread the bacterium around.
Tomato
Bacterial spot, speck and canker – The driving winds and rain (which never seem to go away) have made it ideal for bacterial infections to develop in tomatoes. Tomato transplants with suspected symptoms can be treated with streptomycin (Agri-Mycin 17, Agri-Strep, 25) at 1 lb/100 gallons, or 1.25 teaspoon per gallon every 4 to 5 days prior to transplanting. Additionally, Kocide 3000 (copper hydroxide, FRAC code M1) has a greenhouse label for speck and spot control in the greenhouse. Apply ½ to 1.5 TBSP per 1000 sq ft. every 5 to 10 days. Remember, phytotoxicity is an important issue when apply copper in enclosed structures, see label for cautions, restrictions and liabilities. After transplanting, apply Actigard at 0.33 oz 50WG/A (see label for use), or fixed copper (M1) at 1 lb a.i./A plus a mancozeb (Dithane, Manzate, Penncozeb, M3) at 1.5 lb 75DF or OLF, or ManKocide (M1 + M3) at 2.5 to 5.0 lb 61WP/A on a 7 day schedule.
