Overview. Pre plant considerations. IPM Guide. Bud break to harvest. Southern Highbush Blueberry Disease overview for Florida

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Joella Anderson
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Professor and Extension Specialist UF/IFAS Plant Pathology Department Overview Diseases present challenges at all stages of production Plant propagation considerations Pre bloom through petal fall

sp./spp. 30 No Pathogen Found 23 Phytophthora Root Rot Phytophthora cinnamomi 15 Anthracnose Colletotrichum sp./spp. 10 Blueberry Leaf Rust Pucciniastrum vaccinii 6 Bacterial Wilt Ralstonia solanacearum 5 Algal Cane Blotch or leaf spot Cephaleuros sp.

1 Southern Highbush Blueberry Disease overview for Florida 2017 Blueberry IST, Citra FL Maria C. Philip F. Harmon, Ph.D. Professor and Extension Specialist UF/IFAS Plant Pathology Department Overview Diseases present challenges at all stages of production Plant propagation considerations Pre bloom through petal fall Petal fall through harvest The rest of the year Late spring through summer Summer through winter/ dormancy Disease Happenings 2016 Small Fruit Blueberry 42 Botryosphaeria Stem Blight Botryosphaeria sp./spp. 30 No Pathogen Found 23 Phytophthora Root Rot Phytophthora cinnamomi 15 Anthracnose Colletotrichum sp./spp. 10 Blueberry Leaf Rust Pucciniastrum vaccinii 6 Bacterial Wilt Ralstonia solanacearum 5 Algal Cane Blotch or leaf spot Cephaleuros sp./spp. 4 Blueberry bacterial leaf scorch Xylella fastidiosa 4 Powdery mildew Microsphaera vaccinii 4 Target spot, Corynespora Corynespora sp. 3 Girdling Roots Abiotic disorder 3 Septoria leaf spot Septoria sp./spp. 3 Phomopsis canker/stem blight Phomopsis sp. 2 Phyllosticta Leaf Spot Phyllosticta sp./spp. 2 Mushroom Root Rot Armillaria sp./spp. 1 Botrytis, BRRV, Rhizoctonia, sootymold, crown gall, etc. 340Total for Blueberry Pre plant considerations Pre plant considerations Cutting production, cultivar selection Clean plants, good cultivars Bacterial wilt, crown gall, stem blight, viruses Soil ph, drainage, bed construction Root rot will be severe unless drainage is good Stem blight will be severe where root rot is present remove diseased, dead plants before replant Irrigation requirements Source quality, ph, availability, app method Stem blight will be severe where insufficient or inconsistent Freeze protection Seasonal guide Integrated options Based on the SE guide IPM Guide Bud break to harvest Petal fall through harvest Botrytis blossom blight Fungal fruit rots ripe rot anthracnose gray mold Alternaria Septoria leaf spot Leaf and fruit rust Phytophthora root rot 1

Post harvest Post Harvest Late spring through early summer Anthracnose leaf and stem dieback Septoria leaf spot leaf rust

spot cane and root diseases algal stem blotch root rot stem blight bacterial wilt Management at risk because of multiple

Winter BGA meeting, Plant City, FL, 02/20/14 Resistant to MFR2 2 fungicides MFR3 3 MFR4 4 MFR5 5 MFR6 6 MFR7 7 MFR = The

mummy berry exobasidium viral scorch, stunt or shock nematodes What else?

known as ripe rot (Colletotrichum gloeosporioides and C.

2 Post harvest Post Harvest Late spring through early summer Anthracnose leaf and stem dieback Septoria leaf spot leaf rust algal stem blotch Early summer through late fall leaf diseases rust anthracnose leaf spot Phyllosticta leaf spot target spot cane and root diseases algal stem blotch root rot stem blight bacterial wilt Management at risk because of multiple resistance Phenotype From Amiri, Harmon, & Peres. Winter BGA meeting, Plant City, FL, 02/20/14 Resistant to MFR2 2 fungicides MFR3 3 MFR4 4 MFR5 5 MFR6 6 MFR7 7 MFR = The same botrytis isolate may be resistant to 2, 3, 4 or more fungicides, simultaneously. Anything FL doesn t have? mummy berry exobasidium viral scorch, stunt or shock nematodes What else? anthracnose fruit rot ripe rot Anthracnose There are 3 diseases referred to as anthracnose: Anthracnose fruit rot is also known as ripe rot (Colletotrichum gloeosporioides and C. acutatum) Gloeosporium leaf spot also known as anthracnose leaf spot and known to cause stem cankers as well (Gloeosporium minus) Anthracnose stem canker also known as dieback (Gloeosporium minus?) Not supposed to have structures called setae Dieback and cankers most prevalent on Flicker, also on Scintilla Botrytis blossom blight 2

Anthracnose Central Florida farms reported severe twig dieback,

Colletotrichum as the primary cause A review of spray records showed

tested Growers reported increased incidence of ripe rot in 2014 in

stems were collected and found to be resistant to QoI fungicides

Gloeosporium leaf spot aka anthracnose leaf spot Overlapping colony

3 Anthracnose Central Florida farms reported severe twig dieback, primarily on the Flicker variety in 2013 Samples revealed Colletotrichum as the primary cause A review of spray records showed azoxystrobin use isolates were collected from a handful of farms and tested Growers reported increased incidence of ripe rot in 2014 in central Florida In 2015 and 2016 isolates from fruit, leaves and stems were collected and found to be resistant to QoI fungicides anthracnose stem canker Phyllosticta leaf spot Anthracnose Gloeosporium leaf spot aka anthracnose leaf spot Overlapping colony morphology from berry, stem, and leaf. anthracnose stem canker Control Azoxystrobin Propiconazole 3

Diagnostic protocol Septoria leaf spot Samples from UGA Extension were tested in 2016 using a diagnostic

20 isolates were tested and all from GA were sensitive Managing anthracnose Do not use applications of only

contact fungicides Do not apply more than the labels allow for any one active ingredient for the season

Overhead irrigation has been associated with greater disease severity drip less so Sanitation use sanitizer

4 Diagnostic protocol Septoria leaf spot Samples from UGA Extension were tested in 2016 using a diagnostic protocol at the same time as known resistant and sensitive FL isolates Approx. 20 isolates were tested and all from GA were sensitive Managing anthracnose Do not use applications of only Abound, Cabrio, or Pristine on Flicker post harvest Rotate or tank mix DMI fungicides with compatible contact fungicides Do not apply more than the labels allow for any one active ingredient for the season Change between products with different active ingredients Phyllosticta leaf spot Non fungicide options Overhead irrigation has been associated with greater disease severity drip less so Sanitation use sanitizer on shears when pruning Flicker remove diseased plant material from the field and compost, bury, or burn it as appropriate plant varieties other than Flicker Rust 4

5 Target spot, Corynespora Suspected mite vector Bacterial leaf scorch Xylella Blueberry necrotic ringblotch virus Bacterial leaf scorch Xylella 5

6 Bacterial leaf scorch Xylella Blueberry red ringspot virus Blueberry red ringspot virus Crown Gall (Agrobacterium tumefaciens) Not a common problem as long as plants are free of disease from nursery Causes galls on roots and crowns Where the problem becomes established in a field, plant dips with product like Galltrol at the time of planting may help Blueberry red ringspot virus 6

7 healthy Phytophthora root rot Stem blight discoloration root rot 7

Bacterial Wilt Caused by Ralstonia solanacearum Soil borne bacterium with a wide host range Common scourge of tropical agriculture Very difficult to control where it occurs Infects a wide host range

Similar to bacterial leaf scorch (Xylella) marginal scorching of leaves, dieback, stem blight, plant death symptoms move down the row more rapidly than across Xylem of plants loaded with bacterial

8 Bacterial Wilt Caused by Ralstonia solanacearum Soil borne bacterium with a wide host range Common scourge of tropical agriculture Very difficult to control where it occurs Infects a wide host range of 250 species in 54 families First reported in Florida in 1897 on tomato Occurs commonly on tomato and potato (brown rot) Occasional problem of eggplant and tobacco in the last 100 years Symptoms Similar to bacterial leaf scorch (Xylella) marginal scorching of leaves, dieback, stem blight, plant death symptoms move down the row more rapidly than across Xylem of plants loaded with bacterial ooze clogging vasculature causing wilt Survival and introduction The bacterium is soil and waterborne Once introduced it can survive for years in infested waters including ponds and rivers and in wet soils deeper than 30 in It can survive in plant material without causing symptoms (latent infection) It can survive in weedy hosts (primarily solanaceous, like nightshade) Infection Occurs primarily through roots Wounds formed by lateral root emergence Wounds formed by root damage or feeding (root knot nematode and others) Infection of wounds in stems is also possible Pruning wounds Insect feeding Infection and disease occurs at temperatures above 75F and below 95F Once in the plant, the bacterium spreads through the vasculature 8

9 algal stem blotch 9

Managing algal stem blotch Most fungicides do not work on algae Copper fungicides can help Two to four monthly applications in summer starting after harvest have been reported to keep the disease in

10 Managing algal stem blotch Most fungicides do not work on algae Copper fungicides can help Two to four monthly applications in summer starting after harvest have been reported to keep the disease in check most years by growers Kocide 3000 (also Kocide 2000) as well as several other products and formulations of copper Avoid tank mixes of Cu products with phites and pesticides with EC formulation Other methods? Phosphite fungicides applied for Phytophthora root rot management (but not immediately following copper) may help? Sprayers need to achieve good cane coverage Overhead irrigation will contribute to canopy wetness and disease Farthing, Primadonna, and older plantings of Emerald get the disease, Jewel is not affected Any Questions? Philip Harmon, University of Florida 10

Bacterial Wilt and Bacterial Leaf Scorch on Blueberry in Florida. Deanna Bayo Ph.D. Student Phil Harmon, Ph.D. UF/IFAS Plant Pathology Department

Bacterial Wilt and Bacterial Leaf Scorch on Blueberry in Florida Deanna Bayo Ph.D. Student Phil Harmon, Ph.D. UF/IFAS Plant Pathology Department Bacterial leaf scorch Bacterial leaf scorch caused by Xylella