Agriculture: Pistachio Pest Management Guidelines

Treatment Timing for Key Diseases

Note: not all indicated timings may be necessary for disease control.

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 0 0 0 3 31 1?
Botryosphaeria4 1?5 36 36 3 3 1?
Botrytis 0 3 17 0 0 0
Rating: 3 = most effective, 2 = moderately effective, 1 = least effective, and 0 = 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.
4 Treat once at bloom when the terminals on female trees are 1 to 2 inches long. Begin summer applications in late May or early June. Treat at 2- to 3-week intervals until mid-August. For resistance management, do not apply consecutive applications of any strobilurin (Abound, Flint Extra, or Cabrio) or strobilurin-containing fungicides (Pristine, Luna Sensation), 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.
6 Early season sprays timed before and/or after rains are effective timings in April and May.
7 Protect young clusters if rain and cool weather occurs.

Acknowledgment: Adaskaveg et al., 2022. Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California. (PDF)

Text Updated: 03/22