Managing weeds, pests and diseases

A brief overview of the basic steps that you should take to protect your crops.

The weed Datura ferox (large thorn apple or olieboom) is sometimes found on ploughed land.
Photo: FW Archive

To manage pests in vegetable crops, select a cultivar with resistance to or reasonable tolerance of the diseases or nematodes found in your area. It’s also easier to control pests on land that is well suited to the crop:

  • The soil should have a uniform texture and good drainage.
  • Carry out a soil analysis to determine nutrient deficiencies and salinity. Correct these before planting, as deficiencies or imbalances could cause poor growth, making the plants more prone to attacks by pests.
  • Find out which pesticides have been used on the land previously. Take the waiting period of the product into consideration and make sure that it is safe to plant.

Land preparation
Well-prepared lands and seedbeds encourage healthy plant growth. Break up compacted soil layers before planting. Do not till soil that is too wet; this could cause compaction. Fertiliser will help your crop grow well, stay healthy and produce a good yield. But make sure you apply the fertiliser correctly.

Irrigation
Irrigation scheduling is important. Too much or too little water causes poor growth and weakens resistance to pests and diseases. Apply sprinkler irrigation from planting to seedling stage, then switch to furrow irrigation until harvest. When using sprinklers, avoid runoff and prevent puddles from forming.

Pesticides
Pesticides are convenient and economical, and protect your crop against pests and diseases. But read the label and follow the instructions exactly. If you use pesticides carelessly, you could damage your crop, your health and the environment.
Remember, too, that applying the same pesticide again and again can cause pests to become resistant to it.

Diseases and weeds
To get rid of parasites and other agents of disease, dispose of leftover plant material as soon as possible by chopping up the plants and deep-ploughing the residue or burning it. Control annual weeds, especially before seeding; this will reduce weed competition and crop pests and diseases. To prevent the spread of nematodes do not introduce contaminated soil to your land via equipment, manure or runoff. And use only disease-free seed.

Source: Directorate Communication, department of agriculture in co-operation with the KZN department of agriculture.