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 2015 New Jersey Commercial Vegetable Production Recommendations Guide for more information.
Pepper and Tomato
Phytophthora blight
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 at transplanting and/or 14 days later (between two mefenoxam applications),
-Ranman (cyazofamid, 21) at 2.75 fl oz 400SC at transplanting (Ranman may be added to transplant water, see label for restrictions) and/or 14 days later (between two mefenoxam applications),
-Phosphite materials (FRAC code 33) such as Rampart, ProPhyt, K-Khite may also be tank mixed with one of the above to help suppress Phytophthora blight
Growers with a known history of mefenoxam-insensititivity on their farm should use Presidio or Ranman plus a Phosphite fungicide in rotation. If mefenoxam has not been used in particular fields on any crop for a number of years (more than 5+) the fungus may revert back to being mefenoxam-sensitive.
Organic bell pepper growers with a history of the Phytophthora blight should plant cultivars that have resistance or tolerance to the disease. Long non-host crop rotations are critically important for organic production. Regular applications of Double Nickel (Bacillus amyloliquefaciens) or Regalia (Extract of Reynoutria sachalinensis) as drenches or via the drip system prior to the onset of disease may help suppress Phytophthora blight development.
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.
Strawberry
Anthracnose fruit rot – Anthracnose fruit rot can cause serious losses if not controlled properly. Symptoms of anthracnose include the development of circular, sunken lesions on infect fruit. Often pinkish/tan colored spore masses will develop in the center of lesions. Anthracnose in strawberry is caused by Colletotrichum acutatum. Spore production, germination and fruit infection are favored by warm, humid weather. The fungus can overwinter on infected plants, in plant debris or on weed hosts. Spores are dispersed by splashing water and can infect green and mature fruit.
Application #1:
Captan–3.7 lb 80WDG/A or Thiram 4.4 lb/A 75 WDG tank-mixed with
Pristine–18.5 to 23.0 oz 38 WG/A or Cabrio–12.0 to 14.0 oz 20EG/A
Application #2, apply one of the following:
Captevate–3.5 to 5.25 lb 68WDG/A
Captan–3.7 lb 80WDG/A or OLF
Application #3:
Captan–3.7 lb 80WDG/A or OLF or Thiram 4.4 lb/A 75 WDG tank-mix with
Pristine–18.5 to 23.0 oz 38WG/A or Cabrio–12.0 to 14.0 oz 20EG/A
For subsequent applications, rotate among the following fungicides or fungicide combinations:
Captan–1.9-3.7 lb 80WDG/A or OLF
Elevate–1.1 to 1.5 lb 50WDG/A plus Cabrio–12.0 to 14.0 oz 20EG/A
Pristine–18.5 to 23.0 oz 38WG/A
Switch–11.0 to 14.0 oz. 62.5WG/A plus Cabrio–12.0 to 14.0 oz 20EG/A
When wet weather persists or during bloom, include Elevate or Switch to improve Botrytis control.
Botrytis fruit rot – Gray mold is often a serious problem during extended cool, wet periods when fruit are sizing and reaching maturity. Symptoms of gray mold are the diagnostic grey, fuzzy growth that will cover entire fruit. Control of gray mold, like the other diseases, begins with recognizing the conditions for its development, its symptoms, and preventative fungicide applications. Start sprays when plants begin to bloom, because 90% of fruit infections occur through the flower, and repeat every 7-10 days. Increase spray intervals during persistent dry periods, but decrease intervals to 5-7 days during very wet periods. Four weekly sprays starting at 5-10% bloom are usually sufficient for season-long control. Tank-mix and rotate fungicides from different FRAC codes to reduce the chances for fungicide resistance development.
Application #1, apply one of the following:
Captan–3.7 lb 80WDG/A or OLF
Thiram–4.4 lb/A 75 WDG
Switch–11.0 to 14.0 oz. 62.5WG/A
Application #2, apply one of the following:
If resistance is unlikely on your farm:
Elevate–1.1 to 1.5 lb 50WDG/A
Fontelis–16-24 fl oz/A (except Jewel, L’Amour, and Clancy varieties)
If frequent prior use of the above materials indicates a potential risk for resistance development,
apply one of the following:
Captevate–3.5 to 5.25 lb 68WDG/A
Captan–3.7 lb 80WDG/A or OLF
Thiram–4.4 lb/A 75 WDG
Application #3: same as Application #1
For subsequent applications, rotate between two or more of the following fungicides:
Captan–3.7 lb 80WDG/A,
Captevate–3.5 to 5.25 lb 68WDG/A
Elevate 1.1 to 1.5 lb 50WDG/A
Switch–11.0 to 14.0 oz. 62.5WG/A
Fontelis–16-24 fl oz/A (except Jewel, L’Amour, and Clancy varieties)
Organic strawberry production – Growers need to pay close attention to weed control and keep weeds to a bare minimum within- and in-between rows. Weeds will help create micro-environments that will help trap humidity in the canopy favoring botrytis development. Use a thick layer of mulch in matted row or plastic production to prevent anthracnose spores from being splashed onto the canopy. Avoid overhead irrigation at all costs. Organic materials may offer some suppression of both diseases and will need to be applied regularly. All anthracnose and botrytis-infected fruit should be removed from field.
Tomato
Bacterial spot and speck – 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, 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.
Organic Tomato Production – Stake, tie and/or sucker on hot, sunny days when foliage remains dry or use cages to keep plants upright. Keep weeds to a minimum to prevent conducive microclimates and to help promote airflow. Apply OMRI-approved copper fungicides preventatively on a regular basis prior to symptom development and to help suppress infections. The early red, round varieties such as Red Deuce, Primo Red and others are highly susceptible to bacterial diseases. Plant these away from other tomato varieties if possible. Remove all infected fruit from field.
