West central Michigan vegetable regional report – June 3, 2015
For weeds and diseases, nipping problems in the bud early through prompt action can help minimize problems later in the season.
Asparagus harvest was continuing this week in west central Michigan. Asparagus rust aeciospore lesions were sighted in an Oceana County stand gone to fern. Application of Orius or Tebuzol (active ingredient, or a.i., Tebuconazole) in two- to three-year-old fields can help stop rust problems early, reducing the chances of later-season problems. Rust lesions are orangish and raised above the stalk’s surface; old, purple spot lesions are not raised and may appear sunken. As field shutdown starts to progress, learn more about products and the weeds they target from the vegetable herbicide guide from Michigan State University Extension.
Green bean planting started as of late last week in west central Michigan.
Carrot and celery fields have been colonized by low numbers of aster leafhoppers.
Cole crop damage, likely due to due to cabbage maggots, was visible last week. There are alternatives to chlorpyrifos and bifenthrin for at-plant treatment, including Verimark (a.i. cyantraniliprole) and Coragen (a.i. chlorantraniliprole). These are likely best applied in transplant water as they do not move well in the soil, making banded applications less likely to be effective. Organic growers can place row covers over transplants immediately post-planting as long as a cole crop that could host overwintering cabbage maggot pupae was not present last year.
Onions continue to develop and looked good in Kent County this week. Note, the product Chateau can be incorporated into your rotation. It is primarily a pre-emergence material in onions, so burndown activity will be limited to very small weeds. It can only be tank-mixed with Prowl H20.
Potato volunteers are visible in other parts of the state. Growers should take special care to kill volunteers, which could serve as early season sources of late blight; this is especially important given last year’s epidemic. Colorado potato beetle activity was increasing to the south and east this week with adults, egg masses and small larvae visible.