Reflex / fomesafen

WSSA Resistance Group: 14

Crop/non-crop registration: Soybean, beans

Sensitive weeds: Annual BLW (broadleaf weeds): redroot pigweed, common ragweed, wild mustard, lady's thumb, black nightshade, cocklebur; suppression of lambsquarters and velvetleaf.

Application method: Early POST (crop 1-2 trifoliate, weeds 2-4 leaf stage).

Absorption & Translocation: Taken up readily through foliage (primarily via xylem) but not readily translocated;minimal loss of activity if rainfall occurs at 1 hour or more following application.

Mode of Action: Inhibition of protoporphyrinogen oxidase (PROTOX) enzyme.

Metabolic pathway inhibited: PROTOX is an important enzyme involved in chlorophyll and heme biosynthesis; its inhibition leads to a chain of reactions that ultimately results in lipid peroxidation; lipids and proteins are attacked and oxidized, resulting in loss of chlorophyll and carotenoids and in leaky membranes which allows cells and cell organelles to dry and disintegrate rapidly.

Basis of Selectivity: Metabolized by tolerant species.

Symptoms: Leaves become chlorotic, desiccate, and show signs of necrosis within 1-3 days.

Residuality: Intermediate (1- 4 months); persistence depends on weather and soil conditions (longer under dry conditions); rotation to field corn, soybean and dry beans the following year is not affected; for all

Toxicity: Oral LD50 = 1250-2000 mg/kg - moderately toxic (REFLEX = 8160 mg/kg - practically non-toxic).

Additional comments: Good coverage is essential for optimum weed control; always add an adjuvant such as AGRAL 90; do not apply REFLEX to any field more than once every 2 years; some initial 'bronzing' of younger expanding crop leaves may occur at sub-lethal rates and chlorosis/necrosis at higher rates; however, these plants typically outgrow this effect with no negative impact on maturation or yield.

Images above: Fomesafen (POST) damage on corn. Note: the necrotic spotting on leaves (left). Fomesafen (POST) on velvetleaf (right).

Images above: Fomesafen (POST) on seedling alfalfa (left). Fomesafen (POST) on broadleaf and grass crops and weeds. Note: healthy appearance of soybean in the front flat (right).

Images above: Fomesafen (POST) on common lambsquarters (left). Fomesafen (POST) on wild mustard (right).