Question

1. When activated carbon in the form of wheat char was added to soil, the bioactivity of soil applied herbicides was less effective than when char was not used. Why was that.
   1. Wheat char stimulated the degradation of the herbicide
   2. Wheat char caused a rapid volatilization of the herbicides
   3. Wheat char increased sorption and thus reduced bioavailability
   4. Wheat char stimulated weed growth to such a degree that it outgrew the effects of the herbicide
2. What is the common name of a photosystem II inhibiting pesticide that is detected with more frequency in water of any kind in the United states than any other herbicide with similarity to pharmacodynamic activity? What is the target crop that accounts for over 90% of the use of this pesticide?
   1. Common name of pesticide: __________
   2. Target Crops: __________
3. During pesticide application several mechanisms of spray loss occur between the release from the nozzle and the plant surface. Surfactants added to spray thanks help reduced what type of loss?
   1. Detoxification metabolism of spray residues in leaves
   2. Photodegradation of spray residues on leaf surfaces
   3. Movement of pesticide residues across the leaf surface
   4. Bounce-off of spray particles from leaf surfaces
   5. Evaporation of water used as a carrier for the pesticide active ingredient
4. An active ingredient in a pesticide product has a dermal LD50 greater than 2,000 mg/kg and an oral LD50 over 500 mg/kg. What is the signal word that must appear on the product label? _______

Answer 1

a. Wheat char stimulated the degradation of the herbicide.

Reason:- Activated charcoal adsorbs the water and nutrients thus activating the charcoal. When it absorbs water and nutrients it allows plant roots to access and use these nutrients for growth, but it is also used to absorb harmful chemicals and poisons.

b.

i. Atrazine

ii. Used to stop pre and post emergence of broad leaf and grassy weeds in crops like sorghum, maize, sugarcane, lupines, pine etc...

c. Movement of pesticide residues across te leaf surface.

Adjuvants such as surfactants improve pesticide efficiency by increasing foliar uptake of herbicides, growth regulation and defoliates.

Surfactants allow more contact between the spray droplets and the plant. It does so by reducing the surface tension of the water in the water in the spray solution to that of an solvent, which spread more readily on plant surfaces.