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 ingredient
|
Trade names | Fungicide group | Safety to Typhs | Storage rots controlled |
captan | Captan 80 WDG
PP Captan 80 WG
|
phthalimide | safe | Neonectria
Gloeosporium Colletotrichum Phytophthora |
cyprodinil + fludioxonil | Switch | anilinopyri-midine + cyanopyrrole | safe | Brown rot
Neonectria Penicillium Colletotrichum Fusarium Gloeosporium |
metalaxyl-M + mancozeb
|
Fubol Gold (EAMU 2282/2013 )
|
phenylamide + dithiocarbamate | safe (applied to orchard floor) | Phytophthora |
pyraclostrobin + boscalid | Bellis | strobylurine (QoI)+ anilide | safe | Gloeosporium
Botrytis Penicillium Phytophthora Nectria |
Fungicide sprays for control of storage rots – safety factors
Active ingredient |
Hazards |
Harvest interval (days)
|
Max. no sprays |
Buffer zone | ||
human | fish + aquatic life | bees | width
(m) |
|||
captan
|
h, ir, c | t | u | 31 | 10 | 30 m |
cyprodinil + fludioxonil | a, c | d | u | 3 | 3 | 30 m |
metalaxyl-M + mancozeb
|
h | t | u | bb | 2 | sm |
pyraclostrobin + boscalid | h | d | u | 7 | 4 | 40 m |
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 – wound pathogens – Rot management options
Fungal rot |
Inoculum sources |
Control options |
Penicillium rot |
Dirty fruit bins Damaged fruit |
|
Mucor rot |
Dirty fruit bins Damaged fruit Soil 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 |
Brown rot |
July / August |
orchard incidence high (>1%) |
N/A |
N/A |
|
Orchard incidence low |
N/A |
N/A |
|
||
Botrytis (eye rot) |
August |
N/A |
Moderate-high incidence |
Rain June to Harvest average or > average |
|
Rain June to Harvest < average |
|
||||
N/A |
Low incidence | Rain June-Harvest =average or < average |
|
||
Neonectria rot |
April |
Moderate-high incidence cankered trees |
Moderate – high incidence |
N/A |
Apply fungicide spray in blossom and petal fall |
Low incidence cankered trees |
Low incidence |
N/A |
No fungicide treatment in blossom/petal fall needed |
||
August / September |
Low-high incidence cankered trees |
N/A |
>average rain blossom-harvest |
Market fruit before January if no sprays applied in blossom/petal fall |
|
Moderate-high incidence cankered trees |
N/A |
average rain blossom-harvest |
|||
High incidence cankered trees |
N/A |
Apple orchard diseases – Rot management options continued
Fungal rot |
Assessment timing |
Orchard Risk |
Rain in 15 days pre-harvest |
Decision |
|
% bare ground |
% crop <0.5 m above ground |
||||
Phytophthora rot |
Mid July |
0% = overall grass, weed cover or mulch |
N/A |
N/A |
No sprays needed |
20% or > bareground |
>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 > bareground |
> 15% |
low or no rain = low risk
|
|
||
20 mm or > = high risk
|
if no fungicide treatment applied |
||||
< 15% |
N/A |
No specific action as risk very low |
|||