West central Michigan vegetable update – May 30, 2018

We are looking forward to cooler weather and rain!

Asparagus has been pushed by extremely high temperatures (12-14 degrees Fahrenheit above-normal over the past seven days) for this time of year. Rains and cooler temperatures are eagerly anticipated. Center pivots were running yesterday; irrigation during hot and dry harvest periods can help provide evaporative cooling that reduces open heads.

Common asparagus beetle is causing the most issues I’ve seen since I started my job five years ago, with egglaying leading to quality issues for some growers. Early control failures could possibly have come from applications made during the brief cool period May 20-23. Experience suggests beetles are not active in fields during cool weather. This means applications made at this time after early problems with eggs may not have contacted beetles, and residual product could have been removed after harvest commenced. This is not the whole story though, as some farms have made multiple applications and still had issues. Information on controls is provided again this week.

Product
(active ingredient)

Labelled for pest?

Use patterns

Asparagus
beetle

Tarnished 
plant bug

Japanese
beetle

No. applications per season 
at full rate

Minimum retreatment 
interval

REI/PHI

Assail (acetamiprid)

Yes

Yes

Yes

2

10 days

REI = 12 hr

PHI = 1 day

Carbaryl 4F (carbaryl)

Yes

No

Noa

5 (3 in harvest and 5 total for harvest + fern)

3 days

REI = 12 hr

PHI = 1 day

Lannate (methomyl)

Yes

No

No

5

None

REI = 2 days

PHI = 1 day

Lorsban (chlorpyrifos)

Yes

No

No

3 (1 pre-harvest + 2 post-harvest)

10 days

REI = 2 days

PHI = 1 day

Perm-Up (permethrin)

Yesb

Yes

Yes

4

7 days

REI = 12 hr

PHI = 1 day

Japanese beetle is not listed under asparagus as a target pest, but is listed under other crops as controlled by carbaryl.
Experience suggests permethrin is not as effective as carbaryl for controlling adult beetles.

For celery, aster leafhoppers were collected from Decatur, Michigan, and will be processed for aster yellows infectivity soon.

For cucurbits, winter squash field preparation and planting was ongoing in Ottawa County last week and cucurbit planting was starting in Oceana County. Striped cucumber beetle was spotted in eastern Michigan this week. The major danger of seedcorn maggot damage has likely passed.

For peppers, the bright, sunny hot weather was causing issues for transplants in southwest Michigan as soil dried rapidly. Transplants that were grown in 72 cell trays appear to have set out better than those grown in 128 cell trays. The roots that go out and explore the soil for moisture are not the roots that come out with the plant. New roots have to form. This means the plant has to live on the moisture in the plug for a few days before new roots form, so larger plugs may hold more moisture and do better in dry conditions.

For potatoes, Colorado potato beetle adults, but not eggs, were observed in east Michigan last week. Planting of chip potatoes in Montcalm is behind this year and will likely continue through the first part of June.

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