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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

  • Bin hygiene
  • Selective picking – only sound fruit in the bin
  • Good harvest supervision

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

  • Selective picking at harvest and / or
  • Market fruit early

Orchard incidence low

N/A

N/A

  • Selective picking at harvest

Botrytis (eye rot)

August

N/A

Moderate-high incidence

Rain June to Harvest average or > average

  • Market fruit by January
Rain June to Harvest < average
  • No specific action needed

N/A

Low incidence Rain June-Harvest =average or < average
  • No specific action needed

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

  • 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