Scheduling copper applications and management of greasy ...
Transcript of Scheduling copper applications and management of greasy ...
Scheduling copper applications and management of greasy spot and alternaria brown spot
M. Dewdney1, C. Fraisse2, T. Zortea2, J. Yates1 1University of Florida, IFAS, Citrus Research and Education Center, Lake Alfred
2University of Florida, IFAS, Agricultural and Biological Engineering, Gainesville
Purpose of the Scheduler
•To improve timing of copper sprays over the calendar-based spray schedule of applications every 21 days
•To warn when residue levels are lower than expected
•To avoid unnecessary copper sprays
•To reduce management costs
•To reduce the environmental
impact of copper applications
Diseases Effectively Managed with Copper
• Foliar fungal diseases
– Melanose
– Greasy Spot
– Alternaria brown spot
– Citrus scab
– Black spot
• Non-systemic bacterial diseases
– Citrus canker
Copper Facts
• Copper residue is significantly
reduced by rain washing
• Copper does not move once dried
• Copper residue is cracked by
fruit growth
As the fruit grows, copper must be reapplied to continually cover the fruit as it becomes larger
Proper Application of Copper
•Use label rate recommended for a disease
•Be cautious in hot weather (> 94°F; 34C) –Phytotoxicity can occur more easily in hot weather
•Potential for phytotoxicity can be reduced with greater water volume per acre
•Complex tank mixes, oil applications, and nutritional materials contribute to phytotoxicity
•Aerial applications not likely to get adequate penetration of canopy for control, best method is with an air blast sprayer
How the scheduler operates
•Incorporates rainfall data from FAWN (Florida Automated Weather Network-www.fawn.ifas.ufl.edu) or own weather data
•Incorporates data on copper residue degradation
•Incorporates fruit growth size
•This program may not be
suitable for other citrus production
regions due to varying climatic
conditions and fruit growth habits The blue specks are copper residue
What’s New?
• Lay out
• Select weather option and scion first
• Metric units
Select Bloom
Every 21- day Schedule
• Have insufficient coverage for 6 days
• About perfect timing for third spray
By Forecasts of Scheduler
• Moved first spray up 8 days
• Did not move third spray
What’s New?
• Mobile version www.Agroclimate.org/mobile
– Under tools
Location, Bloom, Spray Date
1
3
2
Cultivar and Results
Gives results in table format
Copper Residue Summer 2011
Valencia
Date
Jun Jul Aug Sep Oct Nov
To
tal d
aily
ra
infa
ll (m
m)
0
20
40
60
80
100
120A
vera
ge
co
pp
er/
surf
ace
are
a (
g/c
m2)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Copper Residue Summer 2011
Grapefruit
Date
Jun Jul Aug Sep Oct Nov
To
tal d
aily
ra
infa
ll (m
m)
0
20
40
60
80
100
120A
vera
ge
co
pp
er/
surf
ace
are
a (
g/c
m2)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Future Plans
• Incorporate additional fruit growth data
– Two seasons collected
– Data collection resumed this year
• Potential Features
– Allow data to be stored on a server to avoid inputting the information every time
– Send alerts, as requested
– Login service
GREASY SPOT
Greasy Spot Disease Cycle Mycosphaerella citri
• Control products
– Copper - All formulations
– Strobilurin fungicides (Abound, Gem, Headline, Quadris Top and Pristine)
• Only once a year for greasy spot
Mar Apr May Jun Jul Aug Sept Oct
Oranges
Valencia
Grapefruit
Greasy Spot Control
• Fungicides effective for greasy spot – Enable – good substitute for copper if concerned
with stippling
• Petroleum oil – Less consistent control on fruit than copper
– Can be mixed with all other fungicides
Further Products
Treatment Metallic Cu (%)
Rate (lbs/acre)
Metallic Cu/acre
Kocide 3000 30 2.0 0.66
Kocide 3000 30 2.5 0.75
Nu-Cop 50 HB 50 2.0 1.00
Nu-Cop 20 HB 20 1.25 0.25
Nu-Cop 20 HB 20 1.875 0.375
Nu-Cop 20 HB 20 2.5 0.50
Basic HB 53 4 2.12
Basic HB 53 8 4.24
Formulations and Products Rates Tested on Grapefruit
Treatment Metallic Cu (%)
Rate (lbs/acre)
Metallic Cu/acre
IQV 40 DF 40 1.5 0.60
IQV 40 DF 40 2.0 0.80
IQV 40 DF 40 2.5 1.00
Untreated Control (UTC) -- -- --
Formulations and Products Rates Cont.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8 a
b bc bcd bcd cde de de e e e e
Greasy Spot Control on Leaves (lb/acre)
0
0.1
0.2
0.3
0.4
0.5
0.6
a ab ab abc bc bcd bcd bcd cde de
ef f
Rind Blotch Control on Fruit (lb/acre)
70
75
80
85
90
95
a ab
abc abc abc bc bc
bc bc c c c
% Marketable Fruit (lb/acre)
ALTERNARIA BROWN SPOT
Alternaria Brown Spot Disease Cycle Caused by Alternaria alternata
• Common control products
– Copper - All formulations
– Strobilurin fungicides (Abound, Gem, Headline, Quadris Top and Pristine)
• If severity high, useful for early sprays but also when hot
Mar Apr May Jun Jul Aug Sept Oct
Tangerines
Alternaria Brown Spot Control
• Ferbam
• Start with clean trees
• Increase air drainage in grove when planting
• Avoid excessive growth promotion
– Too much nitrogen
– Overwatering
– Severe hedging
– High vigour rootstocks
Cultural Controls
Fungicide Resistance
• Where the target population is no longer sensitive enough to a fungicide for sufficient control
• Occurs in response to the repeated use of a fungicide or related fungicides
– Field resistance
• Often becomes apparent with sudden total failure of control
Alternaria alternata isolates recovered in field survey (2010-2011)
Resistant
Sensitive
64% 36%
N = 318
Strobilurin Resistance In Florida
Number of isolates according to cultivar
Cultivar
Dancy Lee Minneola Murcott Orlando Sunburst
No
. Is
ola
tes
0
20
40
60
80
100
120
140
160
Resistant
Sensitive
Alternate Modes of Action?
• Currently registered – Copper
– Ferbam
• Newer products released 2010 – Quadris Top and Pristine
• Mixtures of strobilurins and novel modes of action
– Shown to be efficacious in two years of trials on Alternaria Brown Spot
– Two years of data on Melanose and Greasy Spot Rind blotch also effective
Programs with Pristine in 2010 Program April 20 May 21 June 16 July 7
Program 1 Boscalid (6.5 oz/acre) + Kocide 3000 (2.5 lb/acre)
Kocide 3000 (3.5 lb/acre)
Boscalid (6.5 oz/acre) + Kocide 3000 (2.5 lb/acre)
Kocide 3000 (3.5 lb/acre)
Program 2 Boscalid (6.5 oz/acre)
Kocide 3000 (3.5 lb/acre)
Boscalid (6.5 oz/acre)
Kocide 3000 (3.5 lb/acre)
Program 3
BAS703 (5.48 oz/acre) + Non-ionic surfactant (1 pint/acre)
Kocide 3000 (3.5 lb/acre)
Bas 703 (5.48 oz/acre) + Non-ionic surfactant (1 pint/acre)
Kocide 3000 (3.5 lb/acre)
Program 4 Pristine (18.5 oz/acre)
Kocide 3000 (3.5 lb/acre)
Pristine (18.5 oz/acre)
Kocide 3000 (3.5 lb/acre)
Program 5 Untreated control Untreated control
Untreated control Untreated control
Efficacy on Minneola
TreatmentsUntre
ated control
Program 1
Program 2
Program 3
Program 4
Dis
ea
se
Ra
tin
g
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
a
b b
c c
Treatments
Program 4
Program 3
Program 2
Program 1
Untreated Contro
l
% M
ark
eta
bilit
y
0
10
20
30
40
50
60
70
80
90
100a ab
b b
c
Programs with Quadris Top, 2010
Date April 1 May 4 June 2 June 14 July 9 Aug. 9
Program 1 Untreated control
Untreated control
Untreated control
Untreated control
Untreated control
Untreated control
Program 2 Headline (12 fl oz)
Kocide 3000 (3.5 lb)
Headline (12 fl oz)
Kocide 3000 (3.5 lb)
Kocide 3000 (3.5 lb)
Headline (12 fl oz) + 2% 435 Oil
Program 3 Quadris Top (12 fl oz)
Kocide 3000 (3.5 lb)
Quadris Top (12 fl oz)
Kocide 3000 (3.5 lb)
Kocide 3000 (3.5 lb)
Quadris Top (12 fl oz) + 2% 435 Oil
Program 4 Quadris Top (15.4 fl oz)
Kocide 3000 (3.5 lb)
Quadris Top (15.4 fl oz)
Kocide 3000 (3.5 lb)
Kocide 3000 (3.5 lb)
Quadris Top (15.4 fl oz) + 2% 435 Oil
Program 5 Quadris Top (15.4 fl oz)
SA 123 (6 pints)
Quadris Top (15.4 fl oz)
SA 123 (6 pints)
SA 123 (6 pints)
Quadris Top (15.4 fl oz) + 2% 435 Oil
Program 6 SA 123 (6 pints)
Kocide 3000 (3.5 lb)
SA 123 (6 pints)
Kocide 3000 (3.5 lb)
Kocide 3000 (3.5 lb)
SA 123 (6 pints)
Efficacy on Murcott with Strobilurin Resistance
TreatmentsUntre
ated Control
Program 2
Program 6
Program 3
Program 4
Program 5
Dis
ea
se
Ra
tin
g
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 a
b bc c
d
Treatments
Program 5
Program 3
Program 4
Program 6
Program 2
Untreated Contro
l
% M
ark
eta
bilit
y
0
10
20
30
40
50
60
70
a
b bccd
d
e
Looking for Tangerine Groves
• Sampling for strobilurin resistance
• Want to sample all groves with or without problems
• Contact Megan Dewdney
– CREC ph. 863-956-1151
Questions?