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)