Rot control and management
- Until recently post-harvest fungicide drenches would have been used almost exclusively for control of rotting in store.
- This approach, though scientifically sound and with minimal risk to the operator and to the environment compared to pre-harvest orchard sprays, is no longer acceptable to the consumer and hence markets, because of the high residue remaining on fruit after treatment, which does not decline in store.
- There are no longer any approved products for use on apples as post-harvest fungicide treatments.
- Therefore, the emphasis must be on integrated control using pre-harvest orchard sprays and cultural control methods.
Fungicide sprays for control of storage rots - Efficacy
| Active ingredients | Examples of product | Fungicide group | Safety to Typhs | Storage rots controlled |
|---|---|---|---|---|
| boscalid + pyraclostrobin | Bellis | strobylurine (Qol) + anilide | safe |
Botrytis Gloeosporium Neonectria Penicillium Phytophthora |
| captan | Captan 80 WDG, PP Captan 80 WG, Clayton Core | phthalimide | safe |
Colletotrichum Gloeosporium Neonectria Phytophthora |
| cyprodinil + fludioxonil | Switch | anilinopyrimidine + cyanopyrrole | safe |
Brown rot Colletotrichum Fusarium Gloeosporium Neonectria Penicillium |
| mancozeb + metalaxyl-M | Fubol Gold WG (EAMU 2119/21) | phenylamide + dithiocarbamate | safe (applied to orchard floor) |
Phytophthora |
Fungicide sprays for control of storage rots - safety factors
| Active ingredient | Hazards | Harvest interval (days) | Max. no. sprays | Buffer zone (m) | ||
|---|---|---|---|---|---|---|
| human | fish & aquatic life | bees | ||||
| boscalid + pyraclostrobin | h | t | u | 7 | 4 | 40 |
| captan | h,ir,c | t | u | 31 | 10 | 30 |
| cyprodinil + fludioxonil | a,c | t | u | 3 | 3 | 30 |
| mancozeb + metalaxyl-M | h | t | safe | Pre bb | u | sm |
d = dangerous; h = harmful; ir = irritating, a = may cause allergic reaction, t = toxic
PH = post harvest; Pre bb = pre-bud burst, sm=statutory minimum of 5 m for broadcast air assisted sprayers
u=uncategorised/unclassified/unspecified, c=closed cab required for air assisted sprayers
Apple store diseases - rot management options for wound pathogens
| Fungal rot | Inoculum sources | Control options |
|---|---|---|
| Penicillium rot |
Dirty fruit bins Damaged fruit |
|
| Mucor rot |
Dirty fruit bins Damaged fruit Soin contamination |
|
| Botrytis rot |
Dirty fruit bins Damaged fruit Plant debris |
Apple orchard diseases - rot management options
| Fungal rot | Assessment timing | Orchard risk | Rot history | Rain | Decision |
|---|---|---|---|---|---|
| Botrytis (eye rot) | August | N/A | Moderate-high incidence | Rain June to harvest average or >averarge |
|
| Rain June to harvest <average |
|
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| N/A | Low incidence | Rain June to harvest=average or <average |
|
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| Brown rot | July/August | Orchard incidence high (>1%) | N/A | N/A |
|
| Orchard incidence low | N/A | N/A |
|
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| Neonectria rot | April | Moderate-high incidence cankered trees | Moderate-high incidence | N/A | Apply fungicide spray at blossom and petal fall |
| Low incidence cankered trees | Low incidence | N/A | No fungicide spray at blossom and petal fall needed | ||
| August/September | Low-high incidence cankered trees | N/A | >average rain blossom to harvest | Market fruit before January if no sprays applied at blossom and petal fall | |
| Moderate-high incidence cankered trees | N/A | average rain blossom to harvest | |||
| High incidence cankered trees | N/A |
Apple orchard diseases - rot management options for Phytophthora rot
| Fungal rot | Assessment timing | Orchard risk | Rain in 15 days pre-harvest | Decision | |
|---|---|---|---|---|---|
| % bare ground | % crop <0.5m above ground | ||||
| Phytophthora rot | Mid July | 0% = overall grass, weed cover or mulch | N/A | N/A | No sprays needed |
| 20% or > bare ground | >15% | N/A | Apply fungicide 28 and 14 days pre-harvest or delay action until harvest | ||
| August/September/Harvest | 0% = overall grass, weed cover or mulch | N/A | N/A | No specific action as risk very low | |
| 20% or > bare ground | > 15% | Low or no rain = low risk | No specific action as risk very low | ||
|
20 mm or > = high risk |
Selective pick at harvest or market fruit early to minimise losses if no fungicide treatment applied | ||||
| < 15% | N/A | No specific action as risk very low | |||