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