Frequently Asked Questions

Frequently Asked Questions

  • How much pesticide should I put in a knapsack sprayer ?

    The quantity depends on calibration, but on average 200 litres of water is needed per hectare, so if a knapsack is say 16 litres then proportion may be used.

        As an example, if the application rate is 4 litres per hectare, this means 4 litres is mixed with 200 litres of water. In 16 litres; 16/200 multiplied by 4= 0.32 litres of pesticide in a 16 litre knapsack sprayer.

  • Why should I rotate the pesticides I use ?

    Rotation is done so as to delay the development of resistance by the pests. In any population of pests, there are individuals that may be resistant to a particular pesticide. These individuals will mate and the offspring will be resistant also.

    Because of this, the population of insects will continue to increase despite applying a certain pesticide repeatedly. I the pesticides are rotated, the result is that control will be maintained as it is harder for the pest population to develop resistance simultaneously.

  • At what stage do I apply a pre-emergence herbicide to control weeds ?

    When it pre-emergence control, apply soon after planting in a moist field. The purpose of a moist field is to stimulate germination of the weed seed so that it become vulnerable to the weed killer

  • At what stage do I apply a post emergence herbicide ?

    When it post emergence control, apply before the weeds reach the three leaf stage, otherwise higher rates may then be needed. More mature weeds are more difficult to control because they would have developed a thicker cuticle that   may resist the pesticide

  • What is better, pre-emergence herbicide control or post emergence herbicide control ?

    Pre-emergence control is better because the weeds will not get a chance to emerge and compete with the crop. Post emergence control may result in damage of the crop by machinery and also toxicity by the herbicide being applied

  • At what stage do I apply an insecticide ?

    Application  is done after scouting and when the threshold levels of infestation have been reached that is when it becomes economically viable to intervene with an insecticide. In soe cases a pheromone trap may be used. If a certain number of insects have been lured within a certain time they there will be need to apply an insecticide. Protective insecticides that prevent infestations may be applied even without scouting.

  • At what stage do I apply a fungicide ?

    Protective fungicides may be applied first so as to keep infection at bay. However, after scouting that is when one is encouraged to apply the curative fungicides

  • How to use new chemicals ?

    As a rule of thumb farmers are encouraged to read the label and fully understand it. If in doubt, they are encouraged to consult agritex or other technical experts

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