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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Ramularia leaf spot lesions on artichoke leaf.

Artichoke

Ramularia Leaf Spot

Pathogen: Ramularia cynarae

(Reviewed 1/07, updated 1/07)

In this Guideline:

SYMPTOMS

Ramularia leaf spot is characterized by circular, brown lesions on both upper and lower surfaces of leaves. If disease is severe, lesions will coalesce and the entire leaf will turn brown and dry up. White spores of the fungus will usually develop in leaf lesions. On flower bracts, brown patchy lesions will also form, causing the bracts to curl and dry out.

COMMENTS ON THE DISEASE

Infections on flower bracts usually make the artichoke bud unmarketable.

MANAGEMENT

Consider a fungicide application when flower bract infection follows leaf infection.

Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)
When choosing a pesticide, consider information relating to environmental impact.
 
A. AZOXYSTROBIN
  (Quadris) 11 – 15.4 fl oz 4 0
  MODE OF ACTION: A Qol (Group 11)1 fungicide
  COMMENTS: Do not apply more than one application before alternating with a fungicide that has a different mode of action group number. Do not make more than 4 applications/acre/crop year. Do not apply more than 2.88 pts (1.5 lb a.i.)/acre/crop year. Also controls powdery mildew and Botrytis.
 
B. MYCLOBUTANIL*
  (Rally) 40WSP 2–4 oz 5 48
  MODE OF ACTION: A DMI (Group 3)1 triazole fungicide.
  COMMENTS: Check with your county agricultural commissioner about the availability of this material under a Section 18 registration. Do not apply more than 0.4 lb a.i. acre/year or exceed 4 applications/year.
 
C. BACILLUS PUMILIS#
  (Sonata) 2–4 oz 4 0
  MODE OF ACTION: A biological fungicide.
  COMMENTS: Apply at 7– to 14– day intervals. Can be used in rotation with azoxystrobin or myclobutanil for resistance management in nonorganic fields.
 
 
+  Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the R.E.I. exceeds the P.H.I. The longer of these two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
# Acceptable for use on organically grown produce.
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Fungicides with a different group number are suitable to alternate in a resistance management program. For more information, see http://www.frac.info/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Artichoke
UC ANR Publication 3434
Diseases
S. T. Koike, UC Cooperative Extension, Monterey County
Acknowledgment for contributions to the disease section:
S. Colbert, Griffin Corp., Valdosta, GA

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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