Contact hours : 3 hours of lectures per week plus a three hour practical for 13 week semester

Prerequisite course : Introduction to Weed Science.

Course Content                                                                     Lectures

1. Intergrated Weed Management(IWM)                                            (3)
    definitionand principles. Components of IWM.  Four step
    approach to the development of a weed management
    program

2. Physical method of weed control                                                     (2)
    mow, burn, flood, hoe and hand pull

3. Mechanical methods of weed control                                               (2)
    fast early andinterow cultivation equipment, operating capacity of
    equipment. Advantages/disadvantges of mechanical
    cultivation

4. Cultural (Crop Management) methods of weed control                   (2)
    smother crops, planting  date, plant  populations and
    patterns, late weeds, crop rotations, intercropping.

5. Preventative weed control methods                                                 (2)
    legislative (NoxionsWeed Act, quarantine regulations, seed laws),
    Prevention of seed set and invasion of new lands.

6. Biological weed control                                                                  (2)
    classical/inundative, agents, criteria for success of agents, setting
    up for biological control program.  Costs and time constraint,
    Successes of biological weed control programs. Aquatic weeds and
    biological control.

7. Chemical weed control

    7.1  Introduction to herbicides                                                          (2)
           history of herbicide use advantages and disadvantages of
           herbicide use. Why herbicides have not been readily
           used by small scale farmers in Zimbabwe.
 
 

    7.2  Classification of herbicides according to time and position            (1)
                              of application
           pre plant/pre-emergence soil applied, post emergence
           selective/non selective, lay-bye treatments, Band application.

    7.3  Herbicide movement in the plant                                                (2)
           apoplastic/symplastic/ambimobile. Factors
           affecting activity of apoplastic/symplastically  translocated
           herbicides. Physico - chemical
           determinants of predominant pathway of movememt.

    7.4  Classification of action of herbicides:                                          (3)
           Photosynthetic inhibitors, Pigment synthesis inhibitors, mitotic
           inhibitors, protein synthesis inhibitors, lipid synthesis
           inhibitors membrane disruptors.

    7.6  Mechanisms of selectivity of selective herbicides                         (4)
           Selective mechanisms based on plant morphological
           characteristics and placement "depth control" selectivity.
           penetration/translocation, differential metabolism saffener/
           oynergist activity.

    7.7  Factors that affect efficacy of foliar applied herbicides                (2)
           Structure of the cuticle - hydration and dehydration,
           herbicide formulation, additives and surfactants,
           environmental conditions

    7.8  Factors that affect efficacy of soil applied herbicides                  (2)
           Physical process.  Biological processed, Non biological
           processes.

    7.9  Herbicides evaluation and registration equipment and methods   (2)

8.   Weed control in crops

    8.1    Weed control in Plantation crops                                           (1)
            orchards/vineyardssugarcane

    8.2   Weed control in grain crops                                                   (2)
            maize, sorghum, millet

    8.3   Control in small grain cereals                                                 (1)
            wheat, barley, oats

    8.4   Weed control in cotton/tobacco                                             (1)

    8.5   Weed control in oil seed/legume crop                                     (2)
            soy’s, groundnuts, field beans.
 

    8.6   Control of parasitic weeds                                                     (1)

    8.7   Control of aquatic weeds                                                       (1)

Practicals

1.    Calibration of sprayers for herbicide application

2.    Weed control experiments using machinery

3.    Herbicide movement in the soil - effect of soil texture and amount of water.

4.    Symptoms of damage of foliar applied herbicide and herbicide movement in the plant.

5.    Effect of drift of volatile herbicides, 24D and dicamba.

6.    Herbicide evaluation methods.

7.    Control of parasitic weeds -- pot experiments.