CCA Weed Identification and Control 4

Question 1

Which herbicide mode of action group includes atrazine, simazine, and metribuzin?

Accepted Answer

Group 5 — Photosystem II inhibitors (serine binding)

Answer

Triazines and related compounds (Group 5) inhibit photosystem II at the QB binding site of the D1 protein, blocking electron transport and ultimately causing oxidative damage.

Question 2

Field bindweed (Convolvulus arvensis) is particularly difficult to control because it:

Accepted Answer

Has an extensive deep root system with vegetative reproductive structures

Answer

Field bindweed has a deep, extensive root and rhizome system that can extend 20+ feet deep, enabling regrowth from fragments following tillage or herbicide application.

Question 3

A pre-emergence herbicide is most accurately described as one applied:

Accepted Answer

Before weed seeds germinate, regardless of crop emergence timing

Answer

Pre-emergence herbicides are applied before target weed seedlings emerge from the soil, and they may be applied before or after crop planting.

Question 4

Which of the following is the best example of biological weed control in US crop production?

Accepted Answer

Releasing Rhinocyllus conicus weevils to suppress musk thistle

Answer

Rhinocyllus conicus is a seed head weevil introduced as a classical biocontrol agent for musk thistle (Carduus nutans), a noxious invasive weed.

Question 5

Which weed produces seeds with a pappus (feathery plume) that enables long-distance wind dispersal, making it a major challenge in perennial crops and roadsides?

Accepted Answer

Canada thistle (Cirsium arvense)

Answer

Canada thistle seeds have a feathery pappus that allows them to travel miles on the wind, making containment difficult and spread into new areas common.

(CCA) Certified Crop Advisor Practice Test

(CCA) Certified Crop Advisor Practice Test

CCA Weed Identification and Control 4