If you see thinning or
yellowing on perennial ryegrass in patches – gray leaf spot still may be
active, although I would suspect that weather in the 70s would not allow for
disease to explode rapidly.
Other than that – plenty of rapid blight has
been seen and reported. The socal storms should have brought some relief in the
form of rain – but keep monitoring and leaching as needed. Just a quick word –
some superintendents have been reporting lack of control with Compass or
Insignia. Resistance? We haven’t confirmed anything yet – but we are working
with Mary Olson from the University of Arizona to figure it out. I am less than
optimistic after 5 years of the industry using QoIs repeatedly for control for
the disease, but I am really hoping that we don’t have the big-R word just yet.
Always tank mix with a mancozeb containing fungicide (Fore, Dithane) for cheap
insurance.
Rhizoctonia Diseases
With the storms coming through many parts of
the state this weekend – there should be planty of moisture for Rhizoctonia
diseases – so keep an eye out for those yellow rings on greens.
Take All and Spring Dead Spot – Preventive
Control of Soil Borne Diseases
Soil temps have dropped below 65ºF in many
locations in California, it’s time to treat preventively for Take-All on
bentgrass and Spring Dead Spot on bermudagrass. Preventivel treatment of kikuyugrass
for decline wouldn’t be a bad idea either.
Fungicides available for these diseases are
listed below:
Spring Dead Spot
|
Fungicide |
Class |
Example of available product |
Use Rate (per 1 000 sq. ft) |
No. Applications (X) per season |
|
azoxystrobin |
QoI |
Heritage |
0.4 oz. |
1 to 2X |
|
fenarimol |
SI |
Rubigan |
4.0 to 6.0 fl.oz. |
1X |
|
myclobutanil |
SI |
Eagle |
1.2 oz. |
1 to 2X |
|
propiconazole |
SI |
Banner MAXX |
4.0 fl.oz. |
1 to 3X |
Take All Patch
|
Fungicide |
Class |
Example of available product |
Use Rate (per 1 000 sq. ft) |
Interval (days) or No. Applications (X) |
|
azoxystrobin |
QoI |
Heritage |
0.4 oz. |
2 to 4X |
|
pyraclostrobin |
QoI |
Insignia |
0.9 oz. |
28 |
|
fenarimol |
SI |
Rubigan |
4.0 fl.oz.GT/ 4.0 to 8.0 fl.oz.O |
30 GT/1 to 2X O |
|
propiconazole |
SI |
Banner MAXX |
2.0 to 4.0 fl.oz. |
2 to 4X |
|
triadimefon |
SI |
Bayleton |
1.0 to 2.0 oz. |
21 to 28 |
Decline
|
Fungicide |
Class |
Example of available product |
Use Rate (per 1 000 sq. ft) |
Application Interval (days) |
|
azoxystrobin |
QoI |
Heritage |
0.4 oz. |
14 to 28 |
|
pyraclostrobin |
QoI |
Insignia |
0.9 oz.** |
28 |
|
propiconazole |
SI |
Banner MAXX |
4.0 fl.oz. |
30 |
New
Reporting Format
Finally, I updated the way that I present the
forecast chart – it will come across clearly if you are using an HTML-supported
email program – if it is not clear, let me know and I will try going back to a
non-HTML format.
Weather Updates and Diseases at Risk
Quick 7-day Forecasts; Week of October 16
|
Location |
Highs (ºF) |
Lows (ºF) |
Soil Temps (ºF) |
Weekly Outlook |
Possible Diseases related to Weather |
|||||||
|
Min |
Max |
Min |
Max |
M |
T |
W |
R |
S |
S |
|
||
|
|
70 |
79 |
48 |
54 |
69 |
MS |
S |
S |
S |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch |
|
|
64 |
79 |
54 |
57 |
65 |
PC |
PC |
S |
S |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch, Micodochium Patch (Pink Snow
Mold) |
|
|
65 |
79 |
55 |
58 |
66 |
PC |
MS |
S |
S |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch |
|
|
60 |
70 |
49 |
54 |
64 |
PC |
S |
S |
PC |
MS |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch, Micodochium Patch (Pink Snow
Mold) |
|
|
91 |
93 |
58 |
66 |
71 |
S |
S |
S |
S |
S |
S |
Rhizoctonia Brown Patch of cool season turf, Dollar
Spot, Waitea (Brown Ring) patch, Curvularia Blight |
|
|
70 |
87 |
48 |
53 |
68 |
PC |
MS |
S |
S |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch |
|
|
68 |
80 |
45 |
49 |
64 |
PC |
S |
S |
MS |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch |
|
|
65 |
76 |
57 |
61 |
68 |
PC |
PC |
S |
S |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch, Micodochium Patch (Pink Snow
Mold) |
|
|
60 |
70 |
53 |
57 |
NA |
PC |
S |
S |
PC |
MS |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch, Micodochium Patch (Pink Snow
Mold), Take All Patch |
|
|
65 |
77 |
49 |
55 |
64 |
PC |
S |
S |
PC |
MS |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch, Micodochium Patch (Pink Snow
Mold) |
|
|
67 |
77 |
46 |
53 |
64 |
PC |
MS |
S |
PC |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch |
|
|
66 |
75 |
51 |
57 |
68 |
PC |
MS |
S |
MS |
S |
S |
Rhizoctonia Brown Patch of cool & warm season
turf, Dollar Spot, Waitea (Brown Ring) patch |
soil temps reflect the average of the previous 7 days based
on CIMIS station data at 6-inch depth. S = sunny, MS = mostly sunny, PC =
partially cloudy