Destroy Sources of Disease Infection and Pest Infestation
On a vegetable crop, pests and diseases may survive on volunteer plants (crop plants which come up on their own after the main crop has been harvested). These volunteer plants should be destroyed. The same applies to some weeds which are also hosts of pests and diseases. If an old diseased or pest infested crop remains nearby when a new one is planted, it is likely that the pests or diseases will move over to the new crop.
For example, if spider mites are present on a crop they will surely move to the newly planted. If the old infested crop is upwind the pests will almost certainly be blown onto the new crop. If possible, get rid of the old crop first. If the sticks or canes used to support a crop such as tomato are used for a second time, disease pathogens and pests may be present on them, so they should be washed thoroughly with hot water, dilute bleach or strong soap before being re-used.
Field sanitation is an important and highly effective farm practice to keep most diseases and pests under control. It involves removal and/or destruction of sources of diseases, pest infestation and weeds from the field.
Following practices help to decrease or avoid heavy pest infestation and diseases:
- Keep weeds under control at all times. Keep the surroundings of your farm free of weeds, unless they are maintained and intended as habitat for natural enemies
- Make yourself 'clean'. Always bear in mind that you might be the carrier of the diseases and insect pests while you move from one plant to another
- Pull out plants that are infected or heavily infested by insect pests
- Prune the plant parts where heavy symptoms of disease infection is evident
- Properly dispose of all the infected plants and crop residues after harvesting. Crop residues can be composted, buried underground or burnt
- Pick rotten fruits and collect those that have dropped and bury in a pit
- Plough under the crop residues and organic mulches. This improves soil condition and helps to disrupt the pest's lifecycle. The pest is exposed to extreme temperature, mechanical injury, and predators
- Maintain cleanliness on the irrigation canals
- If possible, remove all the crop residues after harvest. Add these to your compost pile
- Make your own compost. Your compost pile is where you can place your plant trimmings and other plant debris
- Clean your farm tools. Wash ploughs, harrows, shovels, trowels and pruning gears after use. Lightly oil pruning gears
- After weeding out the sick plants (taking care not to rub them against healthy ones, as this can directly transfer the disease to the healthy plant)
Further recommendations related to field sanitation:
Hot-water treatment of seeds can avoid seed borne diseases such as Alternaria spp., Colletotrichum spp., Phoma spp., Septoria spp., and bacterial pathogens (Pseudomonas spp., and Xanthomonas spp).
For more information on hot-water treatment click here
Inspect regularly your crops: Any pest or disease attack should be detected as early as possible and the problem solved before it gets out of hand. Note: The sooner the disease/pest get treated, the better
Practise crop rotation: soil borne pests and diseases such as nematodes, club root in cabbage, damping-off and many others are prevented from building up. Avoid rotating crops of the same family.
Use resistant plants or cultivars
Control aphids and whiteflies: the leaf mottling or curly leaves often show that there are plant viruses building up. They get carried around by suckling insects such as aphids and whiteflies.