Corn flea beetle and Stewart's wilt predictions for 2007
Mike Hoffmann & Jeffrey Gardner, Dept. of Entomology,
Cornell University, Ithaca.
John Gibbons, Ontario Co.
CCE
Stewart's wilt is an important disease of sweet corn in New York. The disease is caused by a bacterial pathogen that is vectored almost exclusively by the corn flea beetle. The bacteria overwinter in the gut of adult flea beetles. In the spring, beetles infest early plantings of corn and transmit the pathogen to the plant by feeding and defecating on leaves. Stewart's wilt is characterized by development of conspicuous streaks on the leaves and stalk due to plugging of vascular tissue. Early wilt infections cause reduction of yield in susceptible varieties by reducing stands due to death or stunting of infected seedlings. Seedlings, which survive early infections, remain stunted, tassel prematurely, and frequently produce no ears or nubbins. Disease severity is aggravated by high temperatures, which causes faster development and movement of the bacteria through the infected plants.
Corn flea beetles spend the winter as adults near the soil
surface in grassy areas in and around cornfields. Severe winter temperatures can kill most of
the population and result in a very low incidence of Stewart's wilt disease the
following summer. Thus, a winter
temperature index is used to predict the likelihood of Stewart's wilt
problems. One forecast uses the number of months
with mean temperatures above 24F for December, January, and
February. The Stewart's wilt index
(likelihood of wilt problems) is as follows:
|
Number of months ³ 24° F |
Predicted risk |
|
0 |
Negligible |
|
1 |
Low
to moderate |
|
2 |
Moderate
to high |
|
3 |
High |
|
|
|
2007 forecast:
The winter of 2006-2007 was a moderate
winter, and the Iowa model predicts moderate to high risk throughout much of
NY. Risk maps can be accessed at http://www.nrcc.cornell.edu/grass/stewart_maps.html.
The model does not account for the number of beetles entering the
winter, the number of surviving beetles that actually carry the pathogen, or
the effect of varietal susceptibility.
Despite these knowledge gaps the model has done well in predicting
relative incidence of Stewart’s wilt.
Management
options for Stewart's wilt disease control include:
1)
planting resistant varieties
2)
planting with treated seed for susceptible varieties
3)
applying a foliar insecticide spray if needed to protect seedling corn.
Tabulated risk of Stewart’s wilt for many locations in NY:
|
|
|
|
Average
°F |
|
|
|
|
Station |
County |
Dec |
Jan |
Feb |
IA
Count |
Risk |
|
ADDISON |
STEUBEN |
35.9 |
28.1 |
15.5 |
2 |
mod-high |
|
ALBANY |
ALBANY |
35.2 |
27.4 |
19.4 |
2 |
mod-high |
|
Albion* |
ORLEANS |
37.2 |
28.6 |
19.1 |
2 |
mod-high |
|
ALCOVE DAM |
ALBANY |
34.9 |
27.6 |
17.6 |
2 |
mod-high |
|
ANGELICA |
ALLEGANY |
35.4 |
26.8 |
15.4 |
2 |
mod-high |
|
Appleton,
North |
NIAGARA |
35.4 |
27.9 |
19.4 |
2 |
mod-high |
|
Appleton,
South |
NIAGARA |
37.7 |
29.6 |
19.8 |
2 |
mod-high |
|
Arkport |
STEUBEN |
35.7 |
27.5 |
16.4 |
2 |
mod-high |
|
AUBURN |
CAYUGA |
36.8 |
27.8 |
17.2 |
2 |
mod-high |
|
AVON |
LIVINGSTON |
37.6 |
28.5 |
18 |
2 |
mod-high |
|
BAINBRIDGE |
CHENANGO |
34.4 |
26.8 |
16.3 |
2 |
mod-high |
|
Batavia |
GENESEE |
36 |
27.5 |
17.6 |
2 |
mod-high |
|
BATH |
STEUBEN |
35.9 |
26.9 |
15.7 |
2 |
mod-high |
|
BINGHAMTON |
BROOME |
35.3 |
27 |
18.2 |
2 |
mod-high |
|
BLOOMINGBURG |
SULLIVAN |
36.3 |
29.5 |
18.7 |
2 |
mod-high |
|
BOONVILLE |
ONEIDA |
29.7 |
19.2 |
10.7 |
1 |
low-mod |
|
Branchport |
YATES |
36.5 |
28.2 |
18.4 |
2 |
mod-high |
|
|
|
|
Average
°F |
|
|
|
|
Station |
County |
Dec |
Jan |
Feb |
IA
Count |
Risk |
|
BRIDGEHAMPTON |
SUFFOLK |
42.9 |
37.4 |
28.1 |
3 |
high |
|
BUFFALO |
ERIE |
37.2 |
28.9 |
18.6 |
2 |
mod-high |
|
CAIRO |
GREENE |
35.2 |
28.7 |
20.3 |
2 |
mod-high |
|
CAMDEN |
ONEIDA |
34 |
22.8 |
13.7 |
1 |
low-mod |
|
CANTON |
ST. LAWRENCE |
33.2 |
16.5 |
11.1 |
1 |
low-mod |
|
CARMEL |
PUTNAM |
37.5 |
29.8 |
21.6 |
2 |
mod-high |
|
CHEMUNG |
CHEMUNG |
35.4 |
28.4 |
17.8 |
2 |
mod-high |
|
COBLESKILL |
SCHOHARIE |
35.4 |
26 |
16 |
2 |
mod-high |
|
CONSTANTIA |
OSWEGO |
34 |
23.4 |
15.4 |
1 |
low-mod |
|
COOPERSTOWN |
OTSEGO |
38.1 |
27.4 |
16.5 |
2 |
mod-high |
|
CORNING |
STEUBEN |
35.5 |
27.7 |
15.8 |
2 |
mod-high |
|
DANSVILLE |
LIVINGSTON |
38.3 |
29.8 |
20.2 |
2 |
mod-high |
|
DANSVILLE |
LIVINGSTON |
37.6 |
29 |
17.4 |
2 |
mod-high |
|
DELHI |
DELAWARE |
34.1 |
27.1 |
16.8 |
2 |
mod-high |
|
DUNKIRK |
CHAUTAUQUA |
38.8 |
28.9 |
19.9 |
2 |
mod-high |
|
EAST JEWETT |
GREENE |
32.4 |
26 |
14.8 |
2 |
mod-high |
|
EAST SIDNEY |
DELAWARE |
34.7 |
26.4 |
16 |
2 |
mod-high |
|
Elba |
GENESEE |
34.5 |
25.9 |
16.5 |
2 |
mod-high |
|
ELLENBURG
DEPOT |
CLINTON |
29.6 |
18 |
11.2 |
1 |
low-mod |
|
ELMIRA |
CHEMUNG |
35.7 |
28.8 |
17.4 |
2 |
mod-high |
|
ELMIRA |
CHEMUNG |
35.9 |
28.2 |
18.2 |
2 |
mod-high |
|
FARMINGDALE |
SUFFOLK |
41.5 |
36.1 |
27.8 |
3 |
high |
|
Farmington |
ONTARIO |
37.5 |
29 |
19.3 |
2 |
mod-high |
|
FRANKLINVILLE |
CATTARAUGUS |
34.3 |
26.2 |
15 |
2 |
mod-high |
|
Fredonia |
CHAUTAUQUA |
38.7 |
31.3 |
20.2 |
2 |
mod-high |
|
FULTON |
OSWEGO |
35.3 |
25.7 |
17 |
2 |
mod-high |
|
Gainesville |
WYOMING |
34.1 |
26.2 |
15.5 |
2 |
mod-high |
|
Geneva |
ONTARIO |
36.8 |
28.4 |
18.8 |
2 |
mod-high |
|
GENEVA |
ONTARIO |
37.2 |
27.8 |
17.2 |
2 |
mod-high |
|
GLENS FALLS |
WARREN |
32.6 |
24 |
15.6 |
2 |
mod-high |
|
Groveland |
LIVINGSTON |
37.1 |
29.1 |
19.2 |
2 |
mod-high |
|
HIGHMARKET |
LEWIS |
28 |
17.1 |
8.9 |
1 |
low-mod |
|
Himrod |
YATES |
37.4 |
29.7 |
19.7 |
2 |
mod-high |
|
HONEOYE |
ONTARIO |
38.2 |
29.1 |
18.5 |
2 |
mod-high |
|
HOOKER |
LEWIS |
32 |
20.4 |
12.9 |
1 |
low-mod |
|
HORNELL |
STEUBEN |
34 |
25.8 |
14.7 |
2 |
mod-high |
|
ISLIP |
SUFFOLK |
41.1 |
35.9 |
27.3 |
3 |
high |
|
ITHACA |
TOMPKINS |
36.2 |
28.2 |
16.4 |
2 |
mod-high |
|
JAMESTOWN |
CHAUTAUQUA |
36.1 |
29.4 |
15.5 |
2 |
mod-high |
|
Lansing |
TOMPKINS |
37.6 |
29.8 |
20.3 |
2 |
mod-high |
|
LANSING MANOR |
SCHOHARIE |
36.7 |
27.9 |
18.6 |
2 |
mod-high |
|
LOCK |
CAUYGA |
33.6 |
25.2 |
13.9 |
2 |
mod-high |
|
Lockport |
NIAGARA |
37.9 |
29.5 |
19.9 |
2 |
mod-high |
|
LOWVILLE |
LEWIS |
32.1 |
19.4 |
12 |
1 |
low-mod |
|
LYNDONVILLE |
ORLEANS |
36.1 |
28.5 |
16.2 |
2 |
mod-high |
|
MALONE |
FRANKLIN |
30.3 |
16.8 |
9.3 |
1 |
low-mod |
|
MASSENA |
OTSEGO |
30.5 |
19.1 |
11.2 |
1 |
low-mod |
|
MECKLENBURG |
SCHUYLER |
35.1 |
26.9 |
16.1 |
2 |
mod-high |
|
MONTGOMERY |
ORANGE |
36.8 |
30.9 |
22.4 |
2 |
mod-high |
|
MORRISVILLE |
MADISON |
32.9 |
24 |
14 |
2 |
mod-high |
|
NEW ALBION |
CATTARAUGUS |
33.6 |
26.3 |
13.8 |
2 |
mod-high |
|
NEWCOMB |
ESSEX |
28.2 |
17 |
10.4 |
1 |
low-mod |
|
NORWICH |
CHENANGO |
35.2 |
26.3 |
15.3 |
2 |
mod-high |
|
OCEANSIDE |
NASSAU |
43.6 |
38 |
29.1 |
3 |
high |
|
|
|
|
Average
°F |
|
|
|
|
Station |
County |
Dec |
Jan |
Feb |
IA
Count |
Risk |
|
OLEAN |
CATTARAUGUS |
36 |
28.7 |
17.2 |
2 |
mod-high |
|
ONEONTA |
OTSEGO |
37.2 |
31.2 |
21.6 |
2 |
mod-high |
|
Pavilion |
GENESEE |
35.3 |
26.7 |
17.1 |
2 |
mod-high |
|
PENN YAN |
YATES |
37.2 |
29 |
19.5 |
2 |
mod-high |
|
PISECO |
HAMILTON |
30.2 |
19.4 |
10.8 |
1 |
low-mod |
|
PLATTE CLOVE |
GREENE |
34.2 |
25.9 |
16.9 |
2 |
mod-high |
|
PLATTSBURGH |
CLINTON |
32.2 |
20 |
14.2 |
1 |
low-mod |
|
Potter |
YATES |
35.7 |
28 |
18.1 |
2 |
mod-high |
|
POUGHKEEPSIE |
DUTCHESS |
39.9 |
33 |
24 |
2 |
mod-high |
|
POUGHKEEPSIE |
DUTCHESS |
37.6 |
31.5 |
23.1 |
2 |
mod-high |
|
Prattsburg |
STEUBEN |
34.4 |
26.8 |
16.3 |
2 |
mod-high |
|
RHINEBECK |
DUTCHESS |
36.7 |
30.5 |
20.9 |
2 |
mod-high |
|
ROCHESTER |
MONROE |
39 |
30 |
20.3 |
2 |
mod-high |
|
ROCK HILL |
SULLIVAN |
35.6 |
28.5 |
18.8 |
2 |
mod-high |
|
ROSENDALE |
ULSTER |
39.4 |
30.5 |
24 |
2 |
mod-high |
|
SARANAC |
FRANKLIN |
27.4 |
15 |
8.5 |
1 |
low-mod |
|
Savannah |
GENESEE |
37.2 |
29.1 |
19.8 |
2 |
mod-high |
|
SHERBURNE |
CHENANGO |
34.9 |
26.1 |
16.9 |
2 |
mod-high |
|
SHIRLEY |
CHENANGO |
40.7 |
35.5 |
26.7 |
3 |
high |
|
SILVER CREEK |
CHAUTAUQUA |
39.2 |
33.8 |
20.1 |
2 |
mod-high |
|
SLIDE MOUNTAIN |
ULSTER |
31.8 |
23.6 |
13 |
1 |
low-mod |
|
Sodus |
WAYNE |
36.3 |
27.5 |
18 |
2 |
mod-high |
|
SPENCER |
TIOGA |
35.2 |
27.2 |
16.5 |
2 |
mod-high |
|
STORMVILLE |
DUTCHESS |
37.3 |
30.7 |
21.1 |
2 |
mod-high |
|
STUYVESANT |
COLUMBIA |
36.9 |
28.7 |
20.3 |
2 |
mod-high |
|
SYRACUSE |
ONONDAGA |
38.6 |
28.8 |
19 |
2 |
mod-high |
|
THURSTON |
STEUBEN |
35.7 |
27.9 |
15.7 |
2 |
mod-high |
|
TROY |
RENSSELAER |
37.8 |
26.6 |
19.7 |
2 |
mod-high |
|
TULLY |
CORTLAND |
32.2 |
24.6 |
13.5 |
2 |
mod-high |
|
TUPPER |
FRANKLIN |
29.7 |
16.9 |
8.6 |
1 |
low-mod |
|
Valois |
SCHUYLER |
38 |
29.9 |
19.8 |
2 |
mod-high |
|
WALES |
ERIE |
35.2 |
26.9 |
15.6 |
2 |
mod-high |
|
WARSAW |
WYOMING |
33.4 |
24.3 |
13.8 |
2 |
mod-high |
|
WATERTOWN |
JEFFERSON |
34.8 |
22.5 |
13.8 |
1 |
low-mod |
|
WAVERLY |
TIOGA |
37.2 |
29.9 |
18.5 |
2 |
mod-high |
|
Wayland |
STEUBEN |
35.2 |
27.2 |
16.7 |
2 |
mod-high |
|
WELLSVILLE |
ALLEGANY |
34.8 |
26.6 |
15.1 |
2 |
mod-high |
|
WELLSVILLE |
ALLEGANY |
33.4 |
26.2 |
15.1 |
2 |
mod-high |
|
WEST NYACK |
ROCKLAND |
30 |
19.1 |
9.6 |
1 |
low-mod |
|
WEST POINT |
ORANGE |
39.7 |
32.8 |
23.4 |
2 |
mod-high |
|
WHITE PLAINS |
WESTCHESTER |
40.5 |
34.9 |
25.6 |
3 |
high |
|
WHITEHALL |
WASHINGTON |
28.3 |
19.8 |
15.7 |
1 |
low-mod |
|
WHITNEY POINT |
BROOME |
35.4 |
28 |
15.8 |
2 |
mod-high |
|
Williamson |
WAYNE |
36.9 |
28.7 |
19.3 |
2 |
mod-high |
|
YOUNGSTOWN |
NIAGARA |
38 |
31.4 |
19.3 |
2 |
mod-high |
*
Stations in lower case represent Network for Environment and Weather Awareness
stations.