Storage rot control and management

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
  • Bin hygiene
  • Selective picking - only sound fruit in the bin
  • Good harvest supervision
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
  • Market fruit by January
Rain June to harvest <average
  • No specific action needed
N/A Low incidence Rain June to harvest=average or <average
  • No specific action needed
Brown rot July/August Orchard incidence high (>1%) N/A N/A
  • Selective picking at harvest and/or
  • Market fruit early
Orchard incidence low N/A N/A
  • Selective picking at harvest
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