Properly identifying weed species during their early growth stages can be difficult, but it leads to a more effective weed management plan.

A new Nebraska Extension publication, Identification of Grass Weeds Commonly Found in Agronomic Crops in Nebraska, EC3020, offers general diagrams of grassy plant structures and information on life cycle, habitat, flowering period, and distinguishing features of 12 grasses common to Nebraska fields, along with photos of key identifying features for each grass.

Grasses featured included annual blyegrass, barnyardgrass, Canada wildrye, downy brome, foxtails, Johnsongrass, jointed goatgrass, large crabgrass, longspine sandbur, shattercane, wild oat and wild-proso millet.

The publication authors Debalin Sarangi, weed science postdoctoral research associate, and Amit Jhala, Extension weed management specialist, note the importance of early weed identification and control.

Grass weed species, especially in their early growth stages, are difficult to identify. However, Jhala and Sarangi note that growers shouldn't wait until flowering to control them. Delaying herbicide applications leads to increased early-season crop-weed competition, and reduced control of larger weeds, which will negatively impact crop yield. Early identification can also help in selecting weed management operations.

Take johnsongrass, for example. A perennial weed, johnsongrass produces rhizomes (rootlike structures with a modified underground stem that grows horizontally and produces roots and shoots from its nodes). Implementing moderate tillage can spread this weed species. So, a more appropriate weed management operation would be to apply systemic herbicides at early growth stages.

Given grass weed identification and management are often most effective when weeds are small, the authors recommend using a hand or pocket lens with 10x magnification to improve identification.

This report comes from UNL CropWatch.