| Fungicide | Resistance risk (FRAC)1 | Brownrot | Jacketrot | Anthrac-nose | Shothole | Scab3 | Rust3 | Leafblight | Alternaria leaf spot3 | PM-like5 | Hullrot16 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Abound | high (11) | 4 | 2 | 5 | 4 | 5 | 5 | 4 | 4 | 4 | 4 |
| Adament | medium (3/11) | 5 | 4 | 4 | 5 | 4 | 5 | ND | 4 | 4 | 4 |
| Aproach3,4,7 | high (11) | 4 | 2 | 5 | 4 | 5 | 5 | 4 | 4 | 4 | 4 |
| Bravo, Chlorothalonil,Echo11,12,15 (Equus**) | low (M5) | 3 | NL | 4 | 4 | 4 | 5 | NL | NL | 0 | 0 |
| Bumper, Tilt, Propicure, Propiconazole4 | high (3) | 5 | 1 | 5 | 3 | 3 | 4 | ND | 3 | 4 | 3 |
| Captan4,6,12 | low (M4) | 3 | 3 | 4 | 4 | 3 | 0 | 4 | 2 | 0 | 0 |
| CaptEvate* | low (M4/17) | 4 | 4 | 4 | 4 | 4 | 0 | 4 | 2 | 0 | 0 |
| Cevya | high (3) | 5 | 1 | 5 | 5 | 3/4 | 4 | ND | 4 | ND | 4 |
| Copper + oil14,15 | low (M1) | ND | ND | 0 | 2 | 4 | 0 | 0 | ND | 0 | 0 |
| Copper14,15 | low (M1) | 1 | 1 | 0 | 2 | 2 | 0 | 0 | ND | 0 | 0 |
| Elevate7 | high (17) | 4 | 5 | 0 | 2 | ND | ND | ND | ND | ND | 0 |
| Fervent | medium (3/7) | 5 | 4 | 5 | 4 | 5 | 5 | ND | 5 | 4 | 4 |
| Fontelis3 | high (7) | 5 | 5 | 3 | 5 | 3 | 3 | ND | 4 | ND | 0 |
| Gem3,4,7 | high (11) | 4 | 0 | 5 | 4 | 5 | 5 | 4 | 4 | 4 | 4 |
| Indar | high (3) | 5 | 1 | 4 | 3 | 3 | NL | ND | 2 | ND | 0 |
| Inspire | high (3) | 5 | 3 | 5 | 3 | 4 | 5 | ND | 5 | ND | 4 |
| Inspire Super4 | medium (3/9) | 5 | 5 | ND | 4 | 4 | 5 | ND | 5 | ND | 4 |
| Kenja4 | high (7) | 5 | 5 | 3 | 5 | 4 | 0 | ND | 4 | ND | 0 |
| Laredo, Rally13 | high (3) | 4 | 0 | 3 | 3 | 0 | 2 | 4 | 0 | 4 | 0 |
| Lime sulfur12,15 | low (M2) | 1 | NL | 0 | 1 | 3 | 3 | NL | NL | 0 | 0 |
| Luna Experience3 | medium (3/7) | 5 | 4 | 5 | 4 | 5 | 5 | ND | 5 | 4 | 4 |
| Luna Privilege | high (7) | 4 | 3 | 3 | 3 | 4 | 4 | ND | 4 | 3 | 3 |
| Luna Sensation3,7 | medium (7/11) | 5 | 5 | 5 | 5 | 5 | 5 | ND | 5 | 4 | 4 |
| Mancozeb | low (M3) | 3 | 3 | 4 | 4 | 3 | 4 | 4 | 2 | 0 | 0 |
| Merivon3,7 | medium (7/11) | 5 | 5 | 5 | 5 | 5 | 4 | ND | 5 | 5 | 4 |
| Miravis Duo | medium (3/7) | 5 | 4 | 5 | 4 | 5 | 5 | ND | 5 | 4 | 4 |
| Miravis Prime* | medium (7/12) | 5 | 4 | 5 | 5 | 5 | 5 | ND | 5 | 5 | 4 |
| Ph-D | medium (19) | 3 | 4 | 0 | 3 | 4 | 4 | ND | 5 | ND | 4 |
| PlantShield17 | low (BM 02) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Pristine3,7 | medium (7/11) | 5 | 5 | 5 | 5 | 5 | 4 | ND | 4 | 4 | 4 |
| ProBLAD Verde | low (BM 01) | 3 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Protocol2 | medium–high (1/3) | 5 | 5 | ND | 4 | 4 | 5 | ND | 3 | ND | 2 |
| Quadris Top3 | medium (3/11) | 5 | 5 | 5 | 4 | 5 | 5 | ND | 4 | 4 | 4 |
| Quash4 | high (3) | 5 | 3 | 5 | 4 | 4 | 5 | ND | 5 | 4 | 4 |
| Quilt Xcel, Avaris 2XS3 | medium (3/11) | 5 | 4 | 5 | 4 | 5 | 5 | ND | 4 | 4 | 4 |
| Regev | high (3/BM 02) | 5 | 2 | 4 | 3 | 4 | 4 | ND | 4 | ND | 4 |
| Rhyme | high (3) | 4 | 1 | ND | 2 | 3 | ND | ND | 3 | ND | ND |
| Rovral + oil8,9 | low (2) | 5 | 5 | 0 | 4 | 1 | 3 | ND | 4 | ND | 0 |
| Rovral, Iprodione,Nevado9 | low (2) | 4 | 4 | 0 | 4 | 0 | 0 | ND | 3 | 0 | 0 |
| Scala3,7,10 | high (9) | 5 | 5 | ND | 3 | 0 | ND | ND | 2 | 0 | 0 |
| Sulfur4,12 | low (M2) | 1 | 1 | 0 | 0 | 3 | 3 | 0 | 0 | 4 | 0 |
| Syllit | medium (U12) | 2 | 0 | ND | 4 | 5 | ND | ND | 2 | ND | 0 |
| Tebucon, Toledo, Teb, Tebuconazole | high (3) | 5 | 1 | 4 | 3 | 3 | 4 | ND | 2 | ND | 3 |
| Topsin-M, T-Methyl, Incognito, Cercobin2,6,7,8 | high (1) | 5 | 5 | 0 | 0 | 4 | 2 | 4 | 0 | 3 | 0 |
| Vangard3,7,9,10 | high (9) | 5 | 5 | ND | 3 | 0 | ND | ND | 2 | 0 | 0 |
| Viathon | medium (3/P07,33) | 5 | 1 | 4 | 3 | 3 | 4 | ND | 2 | ND | 3 |
| Ziram | low (M3) | 3 | 2 | 4 | 4 | 4 | 0 | 3 | 2 | 0 | 0 |
FUNGICIDE EFFICACY—PHYTOPHTHORA ROOT AND CROWN ROT (PRCR) USING CONVENTIONAL TREATMENTS
| Fungicide | Resistance risk (FRAC group)1 | PRCR |
|---|---|---|
| Aliette, ProPhyt, Fungi-Phite, K-Phite | low-medium (P07,33) | 4 |
| Orondis | high (49) | 5 |
| Presidio | high (43) | 4 |
| Revus ** | high (40) | 5 |
| Ridomil Gold, Mefenoxam | high (4) | 4 |
| Ridomil, Metalaxyl | high (4) | 3 |
| Rating: 5 = excellent and consistent, 4 = good and reliable, 3 = moderate and variable, 2 = limited and/or erratic, 1 = minimal and often ineffective, 0 = ineffective, NL = not on label, and ND = no data |
| * Registration pending in California. |
| **Not registered, label withdrawn or inactive in California |
| 1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of action. Fungicides with different group numbers are suitable to alternate in a resistance management program. In California, make no more than one application of a fungicide with a mode-of-action group number associated with high resistance risk before rotating to a fungicide with a different mode-of-action group number; for other fungicides, make no more than two consecutive applications before rotating to fungicide with a different mode-of-action group number. |
| 2 Strains of the brown rot fungi Monilinia laxa and M. fructicola resistant to Topsin-M and T-Methyl have been found in some California almond orchards. MBC-resistant strains of the jacket rot fungus, Botrytis cinerea and powdery mildew fungi, have been reported in California on crops other than almond and stone fruits and may have the potential to develop in almonds with overuse of fungicides with similar chemistry. MBC-resistant strains of the scab fungus, Fusicladium (Cladosporium) carpophilum, have been found in California. |
| 3 Field resistance of Alternaria sp. and Fusicladium carpophilum to QoI and SDHI fungicides has been detected in almond orchards. AP-resistant populations of Monilinia spp. have been found on other stone fruit crops in California. |
| 4 Of the materials listed, only sulfur, Abound, Gem, Captan, Kenja, and some of the DMI fungicides (FRAC group No. 3) are registered for use in late spring and early summer when treatment is recommended. |
| 5 PM-like refers to a powdery mildew-like disease on almond fruit that is managed with fungicides. Recent information suggests an Acremonium species is involved. |
| 6 Excellent control obtained when combinations of Topsin-M or T-Methyl and Captan are used. |
| 7 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 per season. |
| 8 Oils recommended include "light" summer oil, 1 to 2% volume/volume. |
| 9 Not registered for use later than 5 weeks after petal fall. |
| 10 Efficacy reduced at high temperatures and relative humidity; experimental for Alternaria. |
| 11 Bravo Ultrex, Bravo WeatherStik, Echo, Echo Ultimate, and Chlorothalonil are currently registered. |
| 12 Do not use in combination with or shortly before or after oil treatment. |
| 13 Efficacy is better in concentrate (80–100 gal/acre) than in dilute sprays. |
| 14 The low rates necessary to avoid phytotoxicity in spring reduce the efficacy of copper. |
| 15 "Burns out" scab twig lesions when applied at delayed dormant. (Chlorothalonil can be applied with dormant oil during tree dormancy). |
| 16 Hull rot ratings are for the disease caused by Rhizopus stolonifer. Ratings for the disease caused by Monilinia spp. will be provided in the future. |
| 17 Plantshield is best used as a wood treatment to prevent silverleaf and wood decay. |
Acknowledgment: Adaskaveg et al., 2022. Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California.