Weeds
Problematic Weeds in no-till production systems - correct answers● Field bindweed
● Johnsongrass
● Hemp dogbane
● Common milkweed
● Yellow nutsedge
Weeds
Forage-type sorghums
(most troublesome to grain sorghum) - correct answers● Shattercane
● Johnsongrass
Weeds
Soy bean problem weeds in northern Missouri - correct answers● Cocklebur
● Common waterhemp
Weeds
Problem weeds in southeastern Missouri - correct answers● Sicklepod
Weeds
The critical weed-free period for these crops is during the first ___________ weeks following crop
emergence because weed competition during this period will reduce yields. - correct answers4 to 6
weeks
Weeds
Soybeans planted in narrow rows, 20 inches apart, require ____ days for the foliar canopy to develop
and provide full soil shading - correct answers45 days
Weeds
,Soybeans planted in rows spaced 30 inches apart require ____ days for full soil shading. - correct
answers60 days
Weeds
A typical weed management strategy for no-till corn and grain sorghum production is to apply a mixture
of a _____________ - correct answersBurndown (herbicide to control existing vegetation)
Weeds
There must be at least ____________ inches of actively growing weed shoot to obtain goo d herbicide
contact. - correct answers8 to 12 inches
Corn Insects
The most severe corn pests include - correct answers● Northern rootworms
● Western rootworms
● European corn borer
● Black cutworm
● Southwestern corn borer
● Fall armyworm
● Corn earworm
Corn Insects
European corn borer - correct answers● Overwinters in Missouri in the pupal stage and can become a
severe pest of corn in later years.
● Adults emerge in the spring, mate and lay eggs in masses of about 30 eggs each.
● Eggs are generally laid on the underside of leaves and have an appearance similar to a small mass of
white fish scales.
Corn Insects
Most corn varieties contain a chemical called ______________ - correct answers● DIMBOA
, Corn Insects
What does DIMBOA do? - correct answers● Provides some resistance from first generation European
corn borer when plants are less than 20-inches tall.
Corn Insects
Occasional corn insect pests: - correct answers● Wireworms
● White grubs
● Grasshoppers
● Grape colaspis
● Dingy cutworm
● True armyworm
● Flea beetles
● Maize billbug
● Chinch bugs
Corn Insects
Fall armyworm - correct answers● Feed deep inside the whorl on developing leaves causing ragged-edge
holes and leaving moist, brown frass.
● Larvae are variable in color, ranging from nearly black to green to light tan. They have three narrow
yellowish-white lines running down the back from the head to the tail. Darker stripes extend down the
side of the body. Black tubercles (bumps) with spines are scattered along the body.
● The moths migrate into Missouri from Gulf Coast states and there two or three generations per year.
In mid-Missouri.
● Treat when 75 percent of plants show leaf feeding and larvae are less than an inch in length, the pest
usually appears in mid July.
Corn Insects
Black cutworm - correct answers● The most important species of several cutworms that attack corn.
● It has a wide host range including the field crops of corn, alfalfa, soybeans, sorghum and cotton.
● Missouri corn fields are at risk of developing an economic infestation approximately once every four
years.
Problematic Weeds in no-till production systems - correct answers● Field bindweed
● Johnsongrass
● Hemp dogbane
● Common milkweed
● Yellow nutsedge
Weeds
Forage-type sorghums
(most troublesome to grain sorghum) - correct answers● Shattercane
● Johnsongrass
Weeds
Soy bean problem weeds in northern Missouri - correct answers● Cocklebur
● Common waterhemp
Weeds
Problem weeds in southeastern Missouri - correct answers● Sicklepod
Weeds
The critical weed-free period for these crops is during the first ___________ weeks following crop
emergence because weed competition during this period will reduce yields. - correct answers4 to 6
weeks
Weeds
Soybeans planted in narrow rows, 20 inches apart, require ____ days for the foliar canopy to develop
and provide full soil shading - correct answers45 days
Weeds
,Soybeans planted in rows spaced 30 inches apart require ____ days for full soil shading. - correct
answers60 days
Weeds
A typical weed management strategy for no-till corn and grain sorghum production is to apply a mixture
of a _____________ - correct answersBurndown (herbicide to control existing vegetation)
Weeds
There must be at least ____________ inches of actively growing weed shoot to obtain goo d herbicide
contact. - correct answers8 to 12 inches
Corn Insects
The most severe corn pests include - correct answers● Northern rootworms
● Western rootworms
● European corn borer
● Black cutworm
● Southwestern corn borer
● Fall armyworm
● Corn earworm
Corn Insects
European corn borer - correct answers● Overwinters in Missouri in the pupal stage and can become a
severe pest of corn in later years.
● Adults emerge in the spring, mate and lay eggs in masses of about 30 eggs each.
● Eggs are generally laid on the underside of leaves and have an appearance similar to a small mass of
white fish scales.
Corn Insects
Most corn varieties contain a chemical called ______________ - correct answers● DIMBOA
, Corn Insects
What does DIMBOA do? - correct answers● Provides some resistance from first generation European
corn borer when plants are less than 20-inches tall.
Corn Insects
Occasional corn insect pests: - correct answers● Wireworms
● White grubs
● Grasshoppers
● Grape colaspis
● Dingy cutworm
● True armyworm
● Flea beetles
● Maize billbug
● Chinch bugs
Corn Insects
Fall armyworm - correct answers● Feed deep inside the whorl on developing leaves causing ragged-edge
holes and leaving moist, brown frass.
● Larvae are variable in color, ranging from nearly black to green to light tan. They have three narrow
yellowish-white lines running down the back from the head to the tail. Darker stripes extend down the
side of the body. Black tubercles (bumps) with spines are scattered along the body.
● The moths migrate into Missouri from Gulf Coast states and there two or three generations per year.
In mid-Missouri.
● Treat when 75 percent of plants show leaf feeding and larvae are less than an inch in length, the pest
usually appears in mid July.
Corn Insects
Black cutworm - correct answers● The most important species of several cutworms that attack corn.
● It has a wide host range including the field crops of corn, alfalfa, soybeans, sorghum and cotton.
● Missouri corn fields are at risk of developing an economic infestation approximately once every four
years.
