East Michigan vegetable regional report – Aug. 5, 2020
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EmailLots of harvesting going on through wet conditions.
Weather
Our region received between 0.97 – 4.12 inches of rain over the last week. Fields are positively muddy. We are predicted to return to summerlike conditions by the end of the week, with another 0.5 inch of rain predicted for the weekend. The medium range forecast suggests warmer than normal, with normal or below-normal precipitation.
You can find more detailed weather information for your area by visiting the Enviroweather station closest to you:
Here is a table that summarizes European corn borer activity, based on Growing Degree Day models. I used Lapeer as an example.
|
|
|
|
Current degree days (Lapeer) |
1,550 |
|
Overwintering generation start to emerge and lay eggs |
450 (occurred 11 June) |
|
Peak flight and egg laying of overwintering generation |
700 (occurred 28 June) |
|
Peak flight and egg laying of 1st generation |
1,700 (occurred 31 July) |
|
Peak flight and egg laying of 2nd generation |
2,450 |
Phytophthora Phthought
This disease is kind of like diabetes of the farm. If diagnosed, you will be living with it and will need to change certain practices and behaviors to reduce its effects on the long-term productivity of your business. It can be overwhelming to read about this plant destroyer. So, here is just one thought at a time for anyone going through this.
With fields as muddy as they are, it is important to power wash the mud off of harvest and transportation equipment between fields that have the disease and fields that do not. Put the powerwasher in a place that is easy to visit and park by so you can make sure you do it. Work last in fields and sections that you know have the disease.
Crop progress and pests
Cole crop harvest continues. There is generally high insect pest pressure, and going forward into the fall, some diseases become more important with increased dew periods.
Sweet corn harvest has been great. Corn earworms are still below treatment threshold according to the traps in the region. One grower shared pictures of corn smut that was ravaging one variety from one planting. This is an interesting disease.
There is little you can do about it really except prevent physical injury to the plant. It can be worse when roots and stalks are damaged from close cultivation that nips the roots, wind lodging and wind sandblasting. So, field position may be at play which makes one variety or planting look worse if it is taking the brunt of the wind.
Also, our droughty period from June to mid-July could have played a roll. In a normal pollination period, the silks and tassels occur at the same time and the silks quickly brown after they get pollinated. Once they are brown, they cannot be infected with smut. In times of drought stress, tasseling and silking don’t line up. Tassels come first and silks linger longer than usual because they are not getting pollinated. This provides an entry for the fungus into the ears. Flowering patterns and response to environmental stress are unique to each variety, and so planting timing and variety are likely at play too.
Pumpkins and most winter squashes are just setting fruit. Powdery mildew pressure seems low this year. Soon after fruit set, plants become very susceptible to it. Spaghetti squash especially. But, I have not seen as much as I would expect this time of year, and with fruit set as far along as it is. That said, I think it is time that serious pumpkin growers start their powdery mildew fungicide programs, if they have not already. Here are the products to consider this year in a rotation, excerpted and modified from the Midwest Vegetable Production Guide.
|
Product (REI/PHI) |
Common Name (FRAC code). Fungicides with a number as the MOA code should be tank- mixed or alternated with a different MOA code according to the label. |
Powdery Mildew |
|
Aprovia Top (12/0) |
difenconazole (3), benzovindiflupyr (7) |
G |
|
Bravo®, Echo®, Equus®, Initiate® (12/0) |
chlorothalonil (M5) |
F |
|
Fontelis® (12/1) |
penthiopyrad (7) |
F |
|
Gatten® (12/0) |
flutianil (U13) |
G |
|
Inspire Super® (12/7) |
difenoconazole (3), cyprodinil (9) |
G |
|
Luna Experience® (12/7) |
fluopyram (7), tebuconazole (3) |
G |
|
Miravis Prime (12/7) |
pydiflumetofen (7), fludioxonil (12) |
ID |
|
Microthiol Disperss (24/0) |
suflur (M2) |
G |
|
Merivon® (12/0) |
fluxapyroxad (7), pyraclostrobin (11) |
F |
|
Monsoon®, Onset®, Toledo®, Vibe® (12/7) |
tebuconazole (3) |
F |
|
Pristine® (12/0) |
boscalid (7), pyraclostrobin (11) |
P |
|
Procure® (12/0) |
triflumizole (3) |
G |
|
Proline® (12/7) |
prothioconazole (3) |
G |
|
Quintec® (12/3) |
quinoxyfen (13) |
G |
|
Rally® (24/0) |
mycolobutanil (3) |
G |
|
Rhyme ® (12/7) |
flutrafiol (3) |
G |
|
Switch 62.5WB® (12/1) |
cyprodinil (9), fludioxanil (12) |
F |
|
Torino® (4/0) |
cyflufenamid (U6) |
F |
|
Vivando® (12/0) |
metrafenone (U8) |
G |
VG=very good. G=good. F=fair. P=poor. S=suppression only. ID=labeled, but insufficient data to allow rating. Based on research and experience of the authors.
Field tomatoes, peppers, and eggplants are being picked. I was delighted to find all three of the prime tomato diseases on one plant this summer. The field had not been sprayed with any fungicides yet, and Alternaria, Anthracnose, and Septoria had all started to move in. Here are the products to consider this year in a rotation, excerpted from the Midwest Vegetable Production Guide.
|
Product (REI/PHI) |
Common Name (FRAC code). Fungicides with a number as the MOA code should be tank- mixed or alternated with a different MOA code according to the label. |
Alternaria |
Anthracnose |
Septoria |
|
Aprovia Top® (12/20) |
benzovindiflupyr (7), difenconazole (3) |
VG |
VG |
VG |
|
Bravo®, Echo®, Equus® (12/0) |
chlorothalonil (M5) |
F |
G |
G |
|
Cabrio® (12/0) |
pyraclostrobin (11) |
VG |
G |
VG |
|
Dithane®, Manzate®, Pennco- zeb® (24/5) |
mancozeb (M3) |
G |
F |
G |
|
Fontelis® (12/0) |
penthiopyrad (7) |
VG |
S |
VG |
|
Inspire Super® (12/0) |
difenconazole (3), cyprodinil (9) |
VG |
F |
G |
|
Luna Sensation® (12/3) |
fluopyram (7), trifloxystrobin (11) |
ID |
S |
VG |
|
Luna Tranquility® (12/1) |
fluopyram (7), pyrimethanil (9) |
VG |
|
VG |
|
Priaxor® (12/0) |
fluxapyroxad (7), pyraclostrobin (11) |
VG |
G |
G |
|
Quadris® (4/0) |
azoxystrobin (11) |
VG |
G |
VG |
|
Quadris Top® (12/0) |
azoxystrobin (11), difenconazole (3) |
VG |
G |
VG |
|
Revus Top® (12/1) |
mandipropamid (40), difenconazole (3) |
G |
G |
G |
|
Tanos® (12/3) |
cymoxanil (27), famoxadone (11) |
G |
F |
G |
VG=very good. G=good. F=fair. P=poor. S=suppression only. ID=labeled, but insufficient data to allow rating. Based on research and experience of the authors.
Great Lakes Vegetable Producer’s Network
MSU is participating in a live weekly roundtable discussion during the growing-season for commercial vegetable producers in the Great Lakes and Midwest region. Join us! We broadcast live via Zoom at 12:30 ET/11:30 CT every Wednesday from the first week of May to the first week of September. Listen live or later here: www.glveg.net/listen. If you have a pressing vegetable production issue that you would like discussed, simply email it, along with your phone number, to greatlakesvegwg@gmail.com.
Next week the topic is hot peppers
Please contact me at phill406@msu.edu or 616-901-7513 with questions, concerns, or to schedule a farm visit. You can also send plant materials to MSU Diagnostic Services.
