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Managing Tomato Diseases in High Tunnels

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Presentation on theme: "Managing Tomato Diseases in High Tunnels"— Presentation transcript:

1 Managing Tomato Diseases in High Tunnels
Kenny Seebold University of Kentucky Plant Pathology Department

2 Diseases in High-Tunnels and Greenhouses
Diseases found in the field are less common in tunnels and greenhouses The most common diseases in structures are favored by high humidity or reduced light levels We also see problems associated with continuous production Disease problems in high tunnels are related to: High humidity, inadequate ventilation, and crowding Introduction of pathogens on planting material, in water, or in soil Pathogen carryover in soil or on surfaces Frequent handling of plants Not as many fungicide choices compared to field production

3 Cultural Controls for Diseases
Sanitation Use bleach or other sanitizer to clean surfaces and tools Remove diseased (or damaged) plants, leaves and fruits quickly Remove plants and roots when the crop is finished “Solarize” tunnel Humidity management Ventilate as much as possible Don’t over-water Cover soil with mulch

4 Avoid Crowding in the Tunnel
More critical with determinate tomatoes

5 Cultural Controls for Diseases
Control weeds and insects Weeds can harbor pathogens and serve as overwintering hosts Weeds can be refuges for insect vectors of disease Insects vector a number of potentially severe diseases Pathogen-free seeds and transplants TSW

6 Common Diseases

7 Botrytis Gray Mold Stem canker ‘Ghost spots’ on fruit Fruit rot
Leaf blight All images: Plant Management Network

8 Botrytis Gray Mold Lettuce
Abundant sporulation (brown to gray) is common when humidity is high Botrytis is favored by moderate temperatures and high humidity “Omnivorous” and always present Weak pathogen that attacks weakened or damaged tissue first

9 Sclerotinia Timber Rot
Sudden wilting Stem canker Sclerotinia thrives in cool, damp conditions Like Botrytis, prefers damaged or weakened tissue

10 Timber Rot Stem canker + sclerotia (overwintering structure)
Mold on stem

11 Leaf Mold upper leaf surface
Caused by Fulvia fulva, favored by high humidity and moderate temps Overwinters in debris, on surfaces, and in soil (spores and sclerotia) Spores can survive for as long as 1 year in soil or on surfaces

12 Leaf Mold lower leaf surface spores (conidia)

13 Managing Foliar Blights & Stem Rots
Minimize wounding / injury of plants in tunnels Remove senescent, injured, or diseased foliage (or entire plants) Manage humidity & ventilation Eradicate weeds and volunteers in and around the high tunnel “Solarize” greenhouse or tunnel during the summer Apply fungicides if needed

14 Fungicides When to treat
Apply when conditions favor disease (before symptoms) OR when first seen Maintain a regular schedule during favorable conditions Thorough coverage is critical Considerations for high tunnel and greenhouse fungicides Make sure product can be used on tomato High tunnels are considered to be greenhouses by the EPA Cannot use chemicals that specifically prohibit greenhouse use Can use if labeled for greenhouse OR if there are no restrictions Know rate, resistance info, and pre-harvest interval For rates listed ‘per acre’, mix in 100 gal of water and spray to runoff

15 Fungicides for High-Tunnel Tomatoes
Product / FRAC Diseases controlled Rate PHI (days) Botran 75 [14] Botrytis gray mold 1 lb/100 gal 10 Catamaran [M] leaf mold, powdery mildew pt/A Copper (Champ*, Kocide, Nu-Cop*, Nordox* [M] fungal leaf blights, powdery mildew, bacterial leaf blights see labels Fontelis [7] Botrytis gray mold, powdery mildew 10-24 fl oz/100 gal Inspire Super [3 / 9] Botrytis gray mold, leaf mold, powdery mildew 16-20 fl oz/100 gal Mancozeb (Dithane, Koverall, Manzate, Penncozeb) [M] fungal leaf blights, powdery mildew 2-3 lb/100 gal 5 Quadris Top [11 / 3] 8-14 fl oz/100 gal *OMRI-listed (can be used in organic production)

16 Less-Common Diseases

17 Tomato Spotted Wilt Tomato Spotted Wilt Virus (TSWV)
Ringspots 1 mm Thrips Ringspots

18 Tomato Spotted Wilt Tomato Spotted Wilt Virus (TSWV)
Ringspots Found in KY on 2/15/2013

19 Management of TSW Monitor for and control insects in tunnels and greenhouses Cultural: Use resistant varieties Don’t plant ornamentals and tomatoes together in the tunnel Remove diseased plants as quickly as possible Clear weeds around tunnels and greenhouses Monitor for and control insects in the high tunnel

20 Root-Knot Nematode Stunting, yellowing, burning on leaf margins
Galls (knots) on roots Affects random clusters of plants at first, will not spread much during a season May eventually spread throughout the high tunnel (over several seasons)

21 Root-Knot Nematode Present in Kentucky, but typically not an economic problem Can build up in tunnels where susceptible crops are grown continuously High risk where soils are light-textured Sanitation & rotation are keys to control Remove plants AND roots after crop is finished Rotation to less-susceptible hosts (not many choices) Solarization between crops Control weeds in the tunnel – especially between crops Plant resistant varieties if possible - code = N, M, or Mi Can apply Vydate L through drip irrigation on some vegetables Use caution – highly toxic Only need this in tunnels with a confirmed nematode problem

22 Long-Term Disease Management
Crop rotation is a good way to limit pathogen buildup in soil In high tunnels, this may not be an option for some Continuous planting of tomatoes can lead to problems: Options: rotation, move tunnel, grow hydroponically, solarize soil Bacterial wilt Root-knot nematode

23 Questions?

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