How to Manage Pests

UC Pest Management Guidelines

Pistachio

2013 Fungicide Efficacy and Treatment Timing

(Reviewed 3/10, updated 10/13)

In this Guideline

FUNGICIDE EFFICACY FOR PISTACHIO DISEASES

Fungicide Resistance risk (FRAC#)1 Alternaria late blight Botrytis blossom & shoot blight Botryosphaeria panicle & shoot blight
Abound high (11) 2,3 +++ ---- +++
Adament** medium (3/11)3 ++ +++ ++
Bravo/Chlorothalonil/(Echo) low (M5) ++ ---- ++
Bumper/Tilt high (3) ++ + ++5
Cabrio high (11) 2,3 +++ ---- +++
Inspire Super medium (3/9) ++ +++ +++(+)
Elevate high (17)3 ND ++++ ND
Fontelis high (7) ++++ +++ +++(+)
Gem high (11) 2,3 +++ ---- +++
Quash high (3) ++++ +++(+) +++5
Luna Experience medium (3/7) ++++ ++++ ++++
Luna Sensation medium (7/11)3 ++++4 ++++ ++++
Merivon*** high (7/11) ++++ ++++ ++++
Pristine high (7/11)3 ++++4 ++++ ++++
Ph-D (Polyoxin-D) medium (19) +++ ++++ +++
Quadris Top medium (3/11)3 +++ ---- +++(+)
Quilt Xcel medium (3/11)3 ++++ ---- +++(+)
Regalia low (natural product) ++ ---- ++9
Scala high (9)3 ++ +++ +++6
Switch high (9/12)3 +++ +++ ++
Tebuzol high (3) +++ + +++5
Topsin-M/T-Methyl/ Incognito7 high (1) ---- ++ ++
Vangard high (9)3 +++ ++++ ----
Copper low (M1) + ---- ----
K-Phite low (33) ND ND ++(+)9
Liquid lime sulfur8 low (M2) ---- ---- +/-
 
Rating: ++++ = excellent and consistent, +++ = good and reliable, ++ = moderate and variable, + = limited and/or erratic, +/- = minimal and often ineffective, ---- = ineffective, and ND = no data
* Registration pending in California.
**Not registered, label withdrawn or inactive.
*** Federal and California registration pending.
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions (for more information, see http://www.frac.info/). Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode of action Group numbers 1, 4, 9, 11, or 17 before rotating to a fungicide with a different mode of action Group number; for fungicides with other Group numbers, make no more than two consecutive applications before rotating to fungicide with a different mode of action Group number.
2 Field resistance of Alternaria spp. to Abound and to other strobilurin fungicides (Gem and Cabrio) is widespread in pistachio orchards.
3 To reduce the risk of resistance development start treatments with a fungicide with a multi-site mode of action; rotate or mix fungicides with different mode of action FRAC numbers for subsequent applications, use labeled rates (preferably the upper range), and limit the total number of applications/season.
4 Resistance to the SDHI (succinate dehydrogenase inhibitor) boscalid has been detected in high levels (80-90%) in some orchards; Pristine should not be applied if resistance to this fungicide is detected in an orchard. Cross-resistance of SDHI fungicides (FRAC Group 7) may occur.
5 Do not apply Bumper/Tilt within 60 days of harvest, Quash within 25 days of harvest, or Tebuzol within 35 days before harvest.
6Under low and moderate disease pressure.
7 Registered for bloom treatment only.
8 Dormant treatment only.
9 Tested only under low disease pressure.

PISTACHIO: TREATMENT TIMING

Disease Dormant Bloom/terminal shoot 1/2-1 inch. (April) Succulent shoot growth /before shell lignification (May) Early Fruit development /after shell lignification (June)1 Fruit development/kernel development(July) Fruit maturation (August)2
Alternaria3 ---- ---- ----- +++ +++1 +?
Botryosphaeria4 +?5 +++6 +++6 +++ +++ +?
Botrytis ---- +++ +7 ---- ---- ----
 
Rating: +++ = most effective, ++ = moderately effective, + = least effective (+/? under revision), and ---- = ineffective
1 If only one application is done, the best timing is late June to early July.
2 Sprays not later than the first week in August.
3 Three applications during the season are recommended.
4Treat once at bloom when the terminals on female trees are 1-2 inches long. Begin summer applications in late May or early June. Treat at 2-3 week intervals until mid-August. For resistance management, do not apply consecutive applications of any strobilurin (Abound, Flint/Gem or Cabrio) or strobilurin-containing fungicides (Pristine, Luna Sensation, Merivon*), and make no more than two applications of a strobilurin or strobilurin-containing fungicide per season.
5 Liquid lime sulfur: some efficacy in some trials, whereas no efficacy in other trials.
6Early season sprays timed before and/or after rains are effective timings in April and May.
7Protect young clusters if rain and cool weather occurs.
*Registration pending.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Pistachio
UC ANR Publication 3461

General Information

Adaskaveg, J. E., B. A. Holtz, T. J. Michailides, and W. D. Gubler. 2013. Efficacy and Timing of Fungicides, Bactericides, and Biologicals for Deciduous Tree Fruit, Nut, Strawberry, and Vine Crops (PDF)

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