Fruit Crops Blackberries

Transcription

1 Diseases of and Fungicides Labeled for Control Disease Fungicides a Efficacy b Rosette (Double Blossom) (Cercosporella rubi) Symptoms: Infected buds give rise to a proliferation of small shoots or witches broom. Infected flower buds give rise to distorted blossoms from which fruit do not develop. Source of Inoculum: The fungus survives in wild blackberries and dewberries. Spores are winddispersed. Control: Eradicate wild blackberries and dewberries in the vicinity. Remove infected blossom clusters before they open. Remove the floricanes immediately after harvest. Follow the fungicide spray schedule. Gray Mold (Botrytis cinerea) Symptoms: The disease results in blighted blossoms and fruit rot and the presence of the characteristic gray fuzzy growth of the pathogen. Source of Inoculum: The fungus survives as sclerotia and on a wide range of plant debris. Spores are winddispersed. Control: Follow the fungicide spray schedule. Abound, Heritage, Quadris(azoxystrobin) Cabrio (pyraclostrobin) c Captan, Captec (captan) Elevate (fenhexamid) Rovral, Iprodione, Nevado (iprodione) Switch (cyprodinil + fludioxonil) +++ Cane Blight (Leptosphaeria coniothyrium) Symptoms: Dark red to purple lesions form on the canes around wounds. Lesions may be on one side of the cane or may girdle it and kill the shoots. Source of Inoculum: The fungus survives in infected tissues and dead canes. Spores are rain splashed. Control: Prune out infected canes and remove floricanes immediately after harvest. Avoid wounding the plants. Cane and Leaf Rust (Kuehneola uredinis) Symptoms: First seen on floricanes in late spring when large yellow pustules split the bark. Small yellow pustules develop on the lower surface of leaves on the floricane and may lead to premature defoliation. Source of Inoculum: The fungus overwinters on infected canes. Spores are wind dispersed. Control: Prune out old diseased canes after harvest. Follow the fungicide spray schedule. Abound (azoxystrobn) Cabrio (pyraclostrobin) Rally (myclobutanil)

2 Disease Fungicides a Efficacy b Orange Rust (Gymnoconia nitens) Symptoms: Disease is evident on new growth in spring as many weak, spindly shoots are formed rather than one strong shoot. Bright orange pustules form on the undersides of infected leaves, and no blooms are produced on the floricanes. Source of Inoculum: The fungus overwinters within systemically infected canes. Spores are winddispersed. Control: Use only disease free planting materials. Remove infected plants as soon as they are observed. Follow the fungicide spray schedule. Septoria Leaf Spot (Septoria rubi) Symptoms: Frogeye lesions with whitish centers and brown to purple margins are produced on leaves. Similar lesions are found on canes and petioles. Source of Inoculum: The fungus overwinters in dead leaves and stems. Spores are wind dispersed. Control: Follow the fungicide spray schedule. Phytophthora Root Rot (Phytophthora spp.) Symptoms: Infected primocanes may rapidly wilt and die in the spring or they (and the floricanes) may slowly become chlorotic, wilt and die in the summer. Infected roots exhibit a reddish brown discoloration of the cortex. Source of Inoculum: The pathogen can be introduced on infected planting material but it also survives in soil. Spreads primarily in water. Control: Use disease free transplants, improve drainage and avoid low spots. Rogue out infected plants and treat surrounding plants with fungicide. Cabrio (pyraclostrobin) Nova, Rally (myclobutanil) Abound, Heritage, Quadris (azoxystrobin) Cabrio (pyraclostrobin) Orbit, Tilt, Bumper (propiconazole) Aliette (aluminum tris) Fosphite, Fungi phite, Helena Prophyt, Phostrol, Rampart (phosphites) a Trade name (chemical name) b Efficacy ratings are on a 1 5 scale where 5 () is the most effective and 1 (+) is the least effective. Ratings are taken from the Southeast Regional Brambles Integrated Management Guide of the Southern Region Small Fruit Consortium ( c For disease suppression only.

3 Fungicide Spray Schedule for Timing Delayed Dormant (bud swell to green tip) Pre bloom (shoots 6 inches and before blooms open) Early Bloom (5 10%) Disease(s) Cane Blight Rusts, Phytophthora Root Rot Full Bloom Petal Fall Cover Sprays Pre harvest (14 days before anticipated harvest) Harvest After Harvest Phytophthora Root Rot, Cane Blight, Rusts and Leaf Spots

4 Fungicides Labeled for Use on Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) aluminum tris Aliette 80WDG 5 45 to 60 day interval; no more than four applications per season; do not mix with copper fungicides azoxystrobin Abound, Heritage, Quadris 2.08F 50WG fluid ounces ounces 7 to 14 day interval; no sequential applications; no more than three applications or 2.88 quarts or 3 per acre per season 11 0 boscalid + pyraclostrobi n Pristine WDG ounces 7 to 14 day interval; no sequential applications; no more than four applications or 92 ounces per acre per season captan Captan, Captec 80 WDG 4L quarts 10 to 14 day interval; no more than 12.5 or 10 quarts per acre per year, respectively M4 3 copper hydroxide Champ, Champion, Kocide, Stretch Metallic copper equivalent 2.16% 15% 24.4% 30% 35% 37.5% 40% 50% 2 6 pints pints pints Apply weekly; discontinue if injury appears; do not use in spray solution with ph less than 6.5 M1 1 2 copper sulfate Cuprofix Disperss, Cuprofix Ultra 40 Disperss Metallic copper equivalent 20% 40% Apply weekly; discontinue if injury appears; do not use in spray solution with ph less than 6.5 M1 0.5

5 Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) cyprodinil + fludioxonil Switch 62.5WG ounces 7 to 10 day interval; no consecutive applications; no more than 56 ounces per crop; follow rotational crop restrictions fenhexamid Elevate 50WDG day interval; no more than two consecutive applications; no more than 6 per acre per season 17 0 iprodione Iprodione Nevado Rovral 50 W 4FL pints See label; no more than four applications per season 2 0 myclobutanil Nova Rally 40W ounces See label; no more than 10 ounces per acre per year 3 0 phosphite (phosphorous acid salts) Fosphite, Fungiphite, Helena Prophyt, Phostrol, Topaz Phosphorous acid equivalent (lb/gal) 1 2 quarts 1 3 quarts 4 pints 4.5 pints See label 33 0 propiconazol e Bumper, Orbit, Tilt 3.6EC 6 fluid ounces See label; no more than 30 fluid ounces per acre per season 3 30 pyraclostrobi n Cabrio 20WDG 14 ounces 7 to 14 day interval; no sequential applications; no more than four applications or 56 ounces per acre per season 11 0 sulfur IAP Dusting Liquid Sulfur Six, Microthiol Disperss, Super Six 53% L 80% 90% 98% 1 2 pints 5 10 (3 15) 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; M2 1

6 Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) Liquid Thiolux Jet, 80% Thiosperse, Wettable Yellow Jacket Dusting Yellow Jacket Wettable Sulfur see label for application intervals