Diseases of and Fungicides Labeled for Control Disease Fungicides a Efficacy b Brown Rot Blossom Blight and/or Fruit Rot (Monilinia spp.) Symptoms: Occurs on all stone fruits. The brown rot fungus causes blossom and twig blight, fruit rot and canker. Affected blossoms turn gray or light brown and are covered with spores if wet weather prevails. The fungus may invade twigs from infected blossoms, causing twig blight or canker. Fruit infection normally occurs as the fruit nears maturity. Small circular light brown spots develop on fruit, often at insect wounds or spots where scab or other diseases occur. These spots enlarge rapidly if the fruit is mature, often rotting the whole fruit. Eventually, the spots become covered with a brownishgray spore mass. Source of Inoculum: The fungus overwinters in peach mummies on the tree or ground and in twig cankers. Control: Remove affected peaches from the orchard at harvest. Remove and bury any peach mummies remaining on the trees before spring. Destroy wild plum thickets, abandoned stone fruit orchards and fence row seedlings as far away as possible from producing trees. Follow the stone fruit fungicide spray program. Rhizopus Rot (Rhizopus spp.) Symptoms: Normally an important postharvest disease of fruit only. Fruit breaks down quickly into a soft watery rot after harvest and is covered with whiskers or raised white fungal growth with little black spores. Source of Inoculum: Spores are present in soil on organic matter and airborne. Control: Avoid wounding the fruit. Practice sanitation within and around the packing shed. Spray with Botran before harvest. Abound, Heritage (azoxystrobin) Adament (tebuconazole + trifloxystrobin) Botran (dichloran) Bravo, Chloronil, Daconil, Equus (chlorothalonil) Captan, Captec (captan) Elevate (fenhexamid) Elite, Orius, Trisum (tebuconazole) fixed copper (copper hydroxide, copper sulfate, cuprous oxide) Gem (trifloxystrobin) c Indar (fenbuconazole) Merivon (fluxapyroxad + pyraclostrobin) Rally, Eagle (myclobutanil) Orbit, Bumper, Propimax, Tilt (propiconazole) Pristine (boscalid + pyraclostrobin) Quash (metconazole) Rovral, Iprodione, Nevado (iprodione) Scala (pyrimethanil) sulfur Thiram (thiram) Topsin, TMethyl, Thiophanate Methyl (thiophanatemethyl) Vangard (cyprodinil) Ziram (ziram) Botran (dichloran) Merivon (fluxapyroxad + pyraclostrobin) + + + + + + ++
Disease Fungicides a Efficacy b Bacterial Spot (Xanthomonas arbicola pv. pruni) Symptoms: The disease occurs on leaves, twigs and fruit of almost all stone fruits. Spots on leaves progress from grayish and watersoaked to deep purple, brown or black and are angular in shape. Spots fall out to give shothole appearance. Fruit are roughened, with cracked, sunken spots. Small, thickedged depressed spots occur on twigs, and larger spots or cankers occur on branches or the trunk. Source of Inoculum: The bacterium survives from one year to the next in twig cankers and is primarily rainsplashed. Control: Obtain healthy, vigorous nursery stock free from bacterial spot cankers. Maintain vigorous growing conditions by proper cultivation and fertilization. Resistant varieties: La. Gold (immune), Bicentennial, La. Premiere (highly resistant), La. Feliciana, Sure Crop, Majestic, Ruston Red and Ouachita Gold. Scab (Cladosporium carpophilum) Symptoms: The disease occurs on leaves, twigs and fruit of almost all stone fruits. Spots on fruit are small, circular, dark olivegreenish, usually about 1/16 to 1/8 inch in diameter. Spots may be distinctly separate or merge, giving a velvety blotch appearance to half or more of the fruit (usually on the attachment end). Spots are superficial, but cracking or distortion of fruit may follow early or severe infection. Source of Inoculum: The fungus lives from year to year in infected twigs. Control: Prune to allow increased air circulation. Avoid lowlying planting sites. Follow the stone fruit fungicide spray schedule. copper (copper hydroxide, copper sulfate, cuprous oxide) FlameOut, Mycoshield (oxytetracycline) Abound, Heritage (azoxystrobin) Adament (tebuconazole + trifloxystrobin) Bravo, Chloronil, Daconil, Equus (chlorothalonil) Captan, Captec (captan) Gem (trifloxystrobin) Indar (fenbuconazole) Merivon (fluxapyroxad + pyraclostrobin) Pristine (boscalid + pyraclostrobin) Quash (metconazole) Rovral, Iprodione, Nevado (iprodione) sulfur Topsin, TMethyl Thiophanate Methyl (thiophanatemethyl) ++ Rust (Tranzschelia discolor) Symptoms: The disease occurs on leaves, twigs and fruit of almost all stone fruits. Brown pustules occur on the lower leaf surface, marked by a yellowish spot on the upper surface. It may cause leaves to drop prematurely, lowering tree vigor. Source of Inoculum: The fungus overwinters as mycelium in twigs or as spores on twigs or leaves clinging to the tree. Control: Follow the stone fruit fungicide spray program. Abound, Heritage (azoxystrobin) Adament (tebuconazole + trifloxystrobin) Elite, Orius, Trisum (tebuconazole) Merivon (fluxapyroxad + pyraclostrobin) Orbit, Bumper, Propimax, Tilt (propiconazole) Pristine (boscalid + pyraclostrobin) Rally, Eagle (myclobutanil)
Disease Fungicides a Efficacy b Peach Leaf Curl (Taphrina deformans) Symptoms: This disease occurs only on peach trees. It has not been a problem in Louisiana, except on firstyear trees. It apparently does not live over the summer here. In spring, when leaves first appear, they are thickened, and as they develop, the blades becomes puffed and folded with the edges curling inward so that the undersurface of the leaf is a series of concave chambers. Affected leaves become reddish or purplish, later becoming reddishyellow and shedding. Source of Inoculum: The fungus lives from one year to the next on limbs or on the ground. Control: Not necessary. Black Knot (Apiosporina (=Dibotryon) morbosum) Symptoms: This disease occurs on plum and cherry. Large, rough, coal black, hard swellings or knots occur along the branches, frequently several inches long. Source of Inoculum: The fungus survives in infected tissue of knots or swellings. Control: Prune and burn diseased branches during the fall or winter, making the cut at least 4 inches below the visible infection. Destroy badly infected trees. Remove wild plums in the vicinity of desirable trees. Bravo, Chloronil, Daconil, Equus (chlorothalonil) copper (copper hydroxide, copper sulfate, cuprous oxide) Thiram (thiram) Ziram (ziram) Bravo, Chloronil, Daconil, Equus (chlorothalonil) Crown Gall (Agrobacterium tumefaciens) Symptoms: Occurs on many fruits including apple, pear, peach and plum. Affects roots and crown of host plant, causing galling of tissue and reduction in the movement of water and nutrients through the plant. Source of Inoculum: This bacterium lives in the soil. Control: Check planting stock for galls or swelling, and rogue infected plants. Treat before planting with Galltrol. Root Rot (Armillaria (= Clitocybe) spp.) Symptoms: Trees appear weak with small yellowish leaves over the entire tree or confined to one or two branches. The entire tree or single branches may die by the end of the summer or the next year. White mycelial growth can be found beneath the bark of roots or base of affected trees at or about the time of death. Source of Inoculum: These fungi live in soil and survive for many years in old, diseased roots. Control: Dig up and burn old roots before planting peach trees. Remove dead trees and as many roots as possible. Fumigate before replanting.
Disease Fungicides a Efficacy b Phony Peach (Xylella fastidiosa) Symptoms: Trees are dwarfed, foliage is abnormally green and fruit remain small. Phony trees have short terminals and profuse lateral branching. Growth starts in the spring earlier than on normal trees. Source of Inoculum: This bacterium lives in infected trees of many species and is spread by xylemfeeding insects and root grafting. Control: Rogue out and burn all infected trees. Also, destroy wild plum and peach seedlings in the area of producing trees. a Trade name (chemical name) b Efficacy ratings are on a 15 scale where 5 (+) is the most effective and 1 (+) is the least effective (for disease suppression only); a implies no benefit. Ratings are taken from the 2007 Southeast Peach, Nectarine and Plum Pest Management and Culture Guide from the University of Georgia (http://www.ent.uga.edu/pubs/peach_guide.pdf). c Labeled for disease suppression only.
Fungicide Spray Schedule for Developmental Stage Timing Disease(s) Dormant After leaf fall and before bud swell Bacterial spot and leaf curl Delayed Dormant 15 percent bud swell Bacterial spot and leaf curl Early Bloom Less than 5 percent bloom Bacterial spot and black knot Bloom Full bloom Blossom blight and black knot Petal fall to 1 percent shuck split Scab, bacterial spot and black knot Postbloom Shuck split to 10 percent shuck off Scab and bacterial spot Summer Cover Sprays Preharvest Seven10 days later Seven to 21day (usually 14day) intervals 21 days before harvest 14 and Seven days (or less) before harvest Scab and bacterial spot Scab and bacterial spot Brown rot (only if disease pressure is high) Brown rot and Rhizopus rot For more detailed information, see the 2009 Southeast Peach, Nectarine and Plum Pest Management and Culture Guide from the University of Georgia (http://www.ent.uga.edu/pubs/peach_guide.pdf).
Fungicides Labeled for Use on Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) aluminum tris azoxystrobin boscalid + pyraclostrobin captan chlorothalonil copper hydroxide Aliette, Legion Abound, Heritage WDG 5 pounds For use on nonbearing trees only! 60day interval; no more than four applications or 20 pounds per acre per ; do not mix with copper fungicides 2.08 F 50 W 6.215.4 fluid 3.28 (see label) Pristine 38 WDG 10.514.5 Captan, Captec Bravo, Chloronil, Chlorothalonil, Daconil, Echo, Equus Champ, Champion, Kocide, Stretch 50 WP 80 WDG 4L 82.5 WDG 6 F Metallic copper equivalent 2.16 percent 15 percent 24.4 percent 30 percent 35 percent 37.5 percent 40 percent 50 percent 48 pounds 2.55 pounds 34 quarts 2.83.8 pounds 3.1254.125 pints Rates are for bacterial spot (see label for rates for other diseases) 1.33 pints 1 pint 0.5 pound 0.75 pound 1 pound 1 pound Seven to 14day interval; no more than two sequential applications; no more than 2.88 quarts or 2.4 pounds per acre per Seven to 14day interval; no more than two sequential applications; no more than five applications or 72.5 per acre per See label for specific crop; no more than 4864 pounds, 3040 pounds or 2432 quarts per acre per year, respectively 18.8 pounds or 20.5 pints See label; for bacterial spot, apply in first and second postbloom cover sprays; do not use in spray solution with ph less than 6.5 33 NA 11 0 7 + 11 0 M4 0 M5 0 Do not apply after shuck split and before harvest M1 21
Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) copper sulfate Cuprofix Metallic copper equivalent 20 percent 40 percent Rates are for bacterial spot (see label for rates for other diseases) 2 5 pounds 12.5 pounds See label; for bacterial spot, apply in first and second postbloom cover sprays; do not use in spray solution with ph less than 6.5 M1 21 Do not apply after shuck split cyprodinil Vangard 75 WDG 5 See label; use only during bloom; no more than 10 per acre per 9 NA dichloran Botran 75 WP 1.335.33 pounds See label 14 10 fenbuconazole Indar 75 WP 2 F 2 6 fluid 1 pound or 2448 fluid per acre per ; do not graze livestock in treated orchards 3 0 fenhexamid Elevate 50 WDG 1.5 pounds (alone) 11.5 pounds (tankmix) two consecutive applications; no more than 6 pounds per acre per 17 0 fluxapyroxad + pyraclostrobin Merivon SC 46.7 fluid two consecutive applications before alternating with a fungicide with a different mode of action; no more than 20.1 fluid per acre per. 7 + 11 0 iprodione Iprodione, Nevado, Rovral 50 WP 4FL 12 pounds 12 pints Only two applications per ; do not apply after petal fall! 2 NA mefenoxam Ridomil EC SL 2 quarts or 1.5 fluid per 1,000 square feet See label; apply in spring before growth starts; Twoto threemonth interval; do not graze livestock in treated orchards 4 0
Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) metconazole Quash 50 WDG 2.53.5 3.54 (peach) No more than two applications after petal fall; no more than three applications or 12 per acre per 3 14 myclobutanil Eagle, Rally 20 EW 40 WP 69 fluid 2.56 84 100 fluid or 2.75 3.25 pounds per acre per year 3 0 oxytetracycline FlameOut, Mycoshield WP 150 ppm See label 18 21 phosphite (phosphorous acid salts) Fosphite, Fungiphite, Helena Prophyt, Phostrol, Topaz Phosphorous acid equivalent (lb/gal) 3.35 3.9 4.2 4.32 12 quarts 13 quarts 2 pints 4.5 pints See label 33 0 propiconazole Orbit, Bumper, Propiconazole, PropiMax, Tilt 3.6 EC 41.8 EC 4 fluid See label; no more than 20 fluid per acre per 3 0 pyrimethanil Scala 600 SC 18 fluid (alone) 9 fluid (tank mix) two applications within 30 days of harvest; no more than three applications when used alone or 54 fluid per acre per ; 9 2 sulfur IAP Dusting Sulfur, Liquid Sulfur Six, Microthiol Disperss, SuperSix Liquid Sulfur, Thiolux Jet, 80 percent Thiosperse,W ettable Sulfur 6 F 80 WP 90 WP 98 WP 1.53.5 pints 1030 pounds 1030 pounds 3560 pounds See label; do not use when hot or when temperatures are expected to be above 90 degrees F over the next three days; do not use within two weeks of an oil spray; see label for application intervals M2 1
Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) tebuconazole Elite, Orius 45 DF 48 three pounds per acre per 3 0 tebuconazole + trifloxystrobin Adament 50 WDG 48 two sequential applications; no more than four applications or 32 per acre per 3 + 11 1 thiophanatemethyl Thiophanate Methyl, TMethyl, Topsin, 4.5 FL 70 WP 85 WDG 2030 fluid 11.5 pounds 0.81.2 pounds 80 fluid, 4 pounds or 3.3 pounds per acre per, respectively 1 1 thiram Thiram 75 WDG 3.95.1 pounds See label; do not graze livestock in treated orchards M3 7 trifloxystrobin Gem 25 W 500 SC 48 1.93.8 fluid two sequential applications; no more than four applications, 32 or 15.2 fluid per acre per 11 1 ziram Ziram 75 WDG 3.758 pounds 40 72 pounds per acre per M3 14