MSU Extension Vegetables

Weather

We have had an unusually high number of low-pressure systems this spring, which has brought us our very wet conditions. Planting of field crops is way behind schedule in the Corn Belt, with seed for short maturity lengths tough to find in some areas.

For the next few days, a warm front will come in from the south bringing warm air and humidity this afternoon through tomorrow morning, May 23. A cold front will come through during the day Thursday, bringing rainfall in the western Lower Peninsula. After the front passes, we will see windy and cool, but dry, weather Thursday. By Friday, another warm front will come from the southern plains, bringing chances for rain late in the day through Saturday. Rainfall could total 0.25-0.5 inch with higher amounts locally. High pressure should move in Sunday and most of Monday with dry weather. Late in the day Monday, another system will move in, and overall week will again bring frequent chances for precipitation. Precipitation totals are expected to be 0.75-1.5 inches over the next week, with higher totals to the west.

In the medium-term, our current weather pattern is forecast to continue through the end of the month, with southwesterly flow and cool, wetter than normal weather. However, some guidance suggests that in early June we may see northwesterly flow, which would mean cooler-than-normal but drier weather.

The weak El Nino that was present this winter is forecast to persist through the growing season; typically, this means wetter than normal weather.

High soil moisture is one of the reasons it has been so cool in parts of the country. This is because solar energy is used to evaporate water, so less is available to warm the landscape up and get crops going. This may be part of the reason crops are “just sitting there.”

Crops

Asparagus harvest has reflected the weather, with slow days interspersed with very big pickings when weather is favorable for growth. Common asparagus beetle was not active Monday in one Oceana County problem field I’ve been monitoring, but keep an eye out as the time is right for activity if we get some warm, sunny days. Check, warm areas that are sheltered from wind in your hotspot fields. Learn about options for control in my MSU Extension article, “Controlling common asparagus beetle during harvest season.”

If you end up with weed escapes this year and don’t want to wait until layby, Lorox (active ingredient linuron), Sandea (active ingredient halosulfuron), Clarity (active ingredient dicamba) and the grass killers have a one-day preharvest interval (PHI). Lorox can kill small broadleaves like lambsquarters, but it can injure spears. Sandea is not killing pigweed like it used to due to resistance issues, but experience suggests it can still slow growth of—but not kill—pigweed. Do not include a surfactant during harvest with Sandea; this will reduce injury. Some growers feel this is beneficial and helps their harvest crews by keeping dense pigweed canopies at bay. Finally, dicamba does have a one-day PHI, but as a hormonal herbicide can cause twisting. It can be used as a spot treatment for problem perennials like thistle but be careful, as over application can severely injure asparagus.

For celery, I have been learning more about carrot weevil this year. This is a very sporadic pest, but contact me at werlingb@msu.edu or 231-873-2129 if you have questions.

Cole crop planting has continued in west Michigan. Cabbage maggot larvae were feeding on turnips in a trial in west Michigan, and activity should peak in the next two weeks. Imported cabbageworm butterflies and eggs and diamondback moth adults have been present in brassica fields. Ask your chemical dealer if Harvanta is available in the pipeline. It is in the same chemical class as Coragen and is labeled for leafy brassicas for caterpillar control. Bt products like Dipel remain good options for organic growers, but need to be applied when caterpillars are small and have a short residual activity.

Onions planted in early April were reportedly doing much better than those planted in late April. Late April onions are just sitting there; at one spot I visited they were in the loop and flag-leaf stage, even after a month in the field. Unfortunately, weeds are also present, but Bernard Zandstra, MSU weeds specialist, recommended waiting until the onions have one true leaf (with a second one coming) to apply herbicides. Our cool, wet conditions combined with the small size of late April sown onions creates a potential for stand reduction with herbicides. Check out Zandstra’s latest onion weed control article for more information.

Sweet corn planting has been ongoing, but cold weather means early plantings aren’t much bigger than later plantings.