The wet spring that delayed planting could complicate weed management.

Late planting is associated with lower weed pressure because mechanically harrowing beds before crop seeding takes out much of the first generation weeds, said Joel Felix, an Oregon State University weed scientist.

But weed management comes with special challenges during a slow-starting crop year.

“We are about two to four weeks behind where we should be” in crop maturity, Felix told Capital Press at the annual Snake River Weed Control Research Tour June 15 at OSU’s Malheur Experiment Station outside Ontario.

Cold weather and rain delayed planting, and wind microbursts killed some emergent plants — so some re-seeding was needed, he said.

Onions, a major crop in southeast Oregon and southwest Idaho, are “starting to look good,” Felix said.

However, herbicide spraying has extended beyond its usual time window due to the crop’s late start, he said. Herbicide application is stretching closer to when the grower would typically start spraying for thrips, a major insect pest in onions.

Chemical application rates and timing thus will be critical as farmers balance weed and pest control with other crop needs — such as taking in nutrients and water most efficiently, and staying healthy, Felix said.

Trials at OSU-Malheur evaluate various herbicides’ effectiveness on crops such as onions, sugar beets, potatoes and oats.

Results vary by chemical and mixture, application timing, how irrigation is incorporated and how a crop is seeded. Findings are important to farmers, seed and chemical companies, and others.

“We need tools like this to manage weeds,” Felix said. That is partly because labor remains in short supply.

But since weeds have started to develop resistance to some herbicides, “we need to identify and develop new products that will be able to manage weeds,” he said.

Chemical companies in recent years have put fewer resources into developing new products, “and therefore, there is a need to look at old chemistries and how they fit into grower weed management needs,” Felix said.