Weed control in specialty crops is the topic for an April  21 presentation at the UNL Panhandle Research and Extension Center.

Integrated Weed Management Specialist Nevin Lawrence will speak at 3 p.m. in the Bluestem Room at the Panhandle Center, 4502 Avenue I.

His talk, enititled “Is the Critical Period of Weed Control an Effective Strategy for Specialty Crops?,” will address an issue affecting several crops important to Panhandle farmers.

Lawrence explained the issue: The critical period of weed control (CPWC) is the period of the crop growth cycle when weed control is necessary to prevent yield loss. Knowing the CPWC can allow herbicide applications or cultivation operations to be targeted to maximize yield while limiting unnecessary costs.

With a movement away from cultivation for weed control and toward conservation agricultural practice, a greater emphasis has been placed on herbicides for weed control. In major crops such as corn, soybean, and wheat, effective weed control is possible throughout the CPWC with herbicides alone. However, minor and specialty crops (such as sugarbeets, dry edible beans, and sunflowers) often lack the herbicide options to provide sufficient control during the CPWC, Lawrence said.

"Is the CPWC an effective strategy for minor and specialty crops?", he asks. What other models of weed control are feasible for managing weeds as growers transition away from tillage?

Lawrence, originally from Casper, Wyo., received his bachelor’s and master’s degrees from the University of Wyoming. His master’s thesis was titled “Glyphosate susceptibility, weed community response, and competitive load following 12 years of selection pressure in a glyphosate-resistant cropping system.” His research during his time in Wyoming focused on crops familiar to the Nebraska Panhandle, including dry beans, sugarbeet, sunflower, and proso millet.

In 2011 Lawrence began a Ph.D program at Washington State University. His dissertation title was “Adaptation to climate change and small grain production systems by Bromus tectorum (cheat grass)." At WSU he conducted weed science research in wheat, garbanzo bean, pea, and lentil crops grown under no-till production practices.

He completed his Ph.D in October 2015 and began as the integrated weed management specialist at the Panhandle REC in January 2016.