Herbicide Carryover Is A Concern For 2013

Drought of 2012 means certain herbicides are more likely to carryover in the soil and cause damage to sensitive rotational crops next year.

Published on: Oct 22, 2012

In some situations, this prolonged persistence will lead to damage to the rotational crop, so you may want to plant a different crop in that field. Owen and Bob Hartzler, another Extension weed management specialist at ISU, have put together a list of factors farmers and crop advisers can use to help determine risk of carryover injury to the rotational crop in a field.

Factors determining the risk of carryover injury include:

* chemical half-life

* rate of herbicide applied

* application date

* soil characteristics (texture, organic matter, pH)

* rainfall (total amount and distribution throughout year)

* sensitivity of rotational crop

* growing conditions following planting next spring

The relative persistence (half-life) and the rate of herbicides used in the field have the greatest impact on the likelihood of herbicide residues injuring the following sensitive crop. However, Owen also says you should keep in mind that only a few of the herbicide active ingredients used in corn and soybean production today have characteristics that may lead to carryover problems in 2013.

Herbicides with carryover potential

High Risk

atrazine (numerous products)

chlorimuron (Authority XL, Canopy, Envive, Valor XLT, others)

imazaquin (Scepter)

simazine (Princep, others)

Moderate to Slight Risk

fomesafen (Reflex, Flexstar, Prefix)

clopyralid (Hornet)

cloransulam (FirstRate, Hornet, Gauntlet, etc.)

imazethapyr (Pursuit)

Dinitroanilines

pendimethalin (Prowl, others)

trifluralin (Treflan, others)

HPPD Inhibitors

isoxaflutole (Balance Flexx)

mesotrione (Callisto, Lumax, Lexar)

tembotrione (Laudis, Capreno)

topramezone (Impact)