Vegetable Disease Update for 2011

1. Vegetable Disease Updatefor 2011 Kenny Seebold Extension Plant Pathologist

2. Topics • BACTERIAL DISEASES OF KENTUCKY VEGETABLES • Bacterial spot of pepper and tomato • Bacterial canker of tomato • Bacterial wilt of cucurbits • Cucurbit yellow vine decline • DÉJÀ VU ALL OVER AGAIN – LATE BLIGHT OF TOMATO IN 2010 • NEW PRODUCTS FOR MANAGING VEGETABLE DISEASES

3. Bacterial Spot of Pepper and Tomato • Common problem in KY peppers and tomatoes • Fast-moving and aggressive in warm and wet weather • Difficult to control once established in greenhouses or fields

4. Bacterial SpotFoliar symptoms Pepper Tomato

5. Bacterial SpotFruit symptoms Tomato Pepper

6. Bacterial SpotDevelopment and Spread • Caused by Xanthomonas campestrispv. vesicatoria • Seed- and transplant-borne • Plants susceptible at all growth stages • Favored by warm and wet weather • Spread by rain splash or mechanical means • Pathogen can survive for up to a year in debris

7. Bacterial SpotManagement • Prevention is the best defense… • Use pathogen-free seed • Use caution when saving seed from non-hybrid varieties • Hot water treatment (refer to ID-36 for instructions) • Pepper: use a bacterial spot-resistant variety • Resistance available to races 1, 2, 3, and 5 of the BLS pathogen • Choose a variety with resistance to as many races as possible • Rotate regularly with non-host crops • Control weeds, avoid overhead irrigation and working wet plants • NEVER transplant diseased seedlings

8. Bacterial SpotInfected transplants set in the field 30 acres of pepper affected – 2010

9. Chemical Control of Bacterial SpotConventional production • Treat transplants with streptomycin • 1 lb / 100 gal or 1-2 tsp per gal • Apply 2-3 times in greenhouse, once before going to field • Fixed copper + mancozeb or maneb(1.5 – 3 lb/A) • Tomato and pepper: Coppers=Kocide, Champ, etc; can be used in greenhouse • Tomato: Mancozeb=Dithane, Manzate, etc.; can be used in greenhouse • Tomato and pepper: Maneb=Maneb or Manex; may be difficult to find • Apply products on a regular schedule – timing depends on weather • Actigard 50WG (0.33 – 0.75 oz/A) • Tomato and chile pepper • Apply on a 14-day schedule beginning 1 week after transplant • No more than 4 applications • May see reduced fruit size & weight • Actigard can be omitted from spray programs – make sure to spray copper + mancozeb regularly

10. Control of Bacterial SpotOrganic production • Sound cultural practices are critical • Pepper: plant a BLS-resistant variety if at all possible • Apply OMRI-approved fixed coppers routinely Examples: • Badge X2 • Champ WG • Cueva Fungicide Concentrate • Nordox 75WG and Nordox 30/30 WG • Nu Cop 50WP • Ortho Elementals Garden Disease Control

11. Bacterial Canker of TomatoClavibactermichigensis subsp. michiganensis Marginal leaf burn (firing)

12. Bacterial Canker Wilting Stem canker Pith necrosis Pith necrosis

13. Bacterial Canker Bird’s eye spots on fruit

14. Bacterial CankerDevelopment and Spread • Seed- and transplant-borne • Overwinters on plant debris, stakes, equipment etc. • Plants susceptible at all growth stages • Favored by high moisture and moderate-to-warm temperatures • Easily spread by contact (people) and rain splash

15. Bacterial CankerManagement • Prevention is the most effective way to manage canker • Suggested Practices: • Rotation (3+ years away from problem fields) • Use pathogen-free seeds and transplants • DO NOT SAVE SEED FROM CANKER-INFESTED CROPS • Avoid overhead irrigation and handling wet plants • Apply streptomycin prior to transplanting • Remove symptomatic plants ASAP • Fixed copper + maneb or mancozeb(1.5-3 lb/A) – 7 day intervals • Will not eradicate pathogen, but keeps populations low!

16. Bacterial Wilt of Cucurbits Erwiniatracheiphila Affects cucumber, melon primarily & may affect pumpkins, gourds Very widespread in KY EARLY control of cucumber beetle is critical factor for management

17. Bacterial Wilt of CucurbitsManagement • Controlling the vector (spotted or striped cucumber beetles) is the key • Vectors will attack crops quickly after transplanting or emergence • Chemicals must be applied at this stage for best disease control: • Imidacloprid (Admire Pro, Nuprid, Widow, etc): systemic material that can be applied as a drench or through drip irrigation. BEST PRACTICE – GIVES 3 TO 5 WEEKS OF CONTROL. • Scout regularly afterward and apply foliar insecticide as needed (see ID-36): • Foliar insecticides include Asana XL, Assail, Brigade, Pounce, and Warrior II • Organic production tips: • Destroy crop residue promptly, rotate to non-cucurbit crops • Use floating row covers as a barrier to cucumber beetles • Apply OMRI-approved materials for suppression of vectors: pyrethrum, kaolin clay (repellent) • Plant trap crops (‘Blue Hubbard’ squash, ‘Dark Green’ zucchini); destroy insects on the trap crop before they spread • Use yellow sticky cards to trap vectors

18. Yellow Vine Decline of Cucurbits Serratiamarcescens Affects melon, pumpkin, squash, & watermelon Source: R. Bessin Very widespread in KY Control of squash bug is critical factor for management

19. Cucurbit Yellow Vine DeclineManagement • Controlling the vector (squash bug) is the primary goal • Vectors will attack crops quickly after transplanting or emergence • Chemicals must be applied at this stage for best disease control: • Imidacloprid (Admire Pro, Nuprid, Widow, etc): apply as for cucumber beetles; will see up to 3 weeks of control. • Apply foliar insecticides; must treat while insects are in the nymphal stage (see ID-36): • Foliar insecticides include Assail, Brigade, Pounce, and Warrior II • Organic production tips: • Destroy crop residue promptly, rotate to non-cucurbit crops • Hand-remove egg masses before they hatch (see ID-91) • Apply OMRI-approved materials for suppression of vectors: pyrethrum, neem oil • Squash bugs may favor no-till or reduced-tillage fields

20. Late Blight of Tomato – Déjà vu all over again! K.W. Seebold, Extension Plant Pathologist

21. Memorial Day Weekend, 2010 Late blight was found on tomato seedlings in several retail garden centers in KY

22. Late Blight of Tomato2010 Outbreak • Diseased transplants were found in large retail garden centers in Boone, Clark, Fayette, and Kenton Counties over a one-week period • Very likely that many infected plants were set in gardens in central and northern KY • Warm weather kept a large-scale epidemic from taking place! • Moving forward - We have to assume that late blight will show up on transplants again. • Urge gardeners and commercial producers to examine plants carefully before buying or transplanting them in the field!

23. NEW Fungicides for 2011

24. Update on Maneb • Maneb fungicides are no longer available: • For some crops (ex. tomato), we can use mancozeb, or other products like chlorothalonil (Bravo) • Need maneb to mix with copper for bacterial spot control on pepper • Need maneb as a rotation partner for fungicides like Quadris (ex. pepper) • The EPA has been petitioned to add brassicas, lettuce, peppers, pumpkins, & winter squash to Section 3 mancozeb labels • Will be approved by March 31, 2011 (?!?)

25. Nordox 75WGBrandt • Fungicide / Bactericide • Broad spectrum • Cuprous oxide • FRAC Group M • OMRI approved • 75% wettable granule • 1.25 to 2.5 lb/A use rate • Field and greenhouse use • REI • 12 hours • PHI • 0 days • Brassicas (head and stem) • Bulb vegetables • Cucurbits • Fruiting vegetables • Leafy vegetables

26. Questions?