Agriculture Reference
In-Depth Information
10.
Diseases and Disorders
Peppers are susceptible to a number of diseases and disorders typically caused by
bugs and environmental conditions. This section teaches you about the common diseases
and disorders, how to spot the early signs and how to treat them.
Diseases
Bacterial Leaf Spot
- bacterial leaf spot (BLS) is one of the most common and de-
structive diseases of peppers. Signs of infection include leaf spotting which is water-soaked
initially, changing color (yellow, brown) and becoming deformed before dropping off. The
peppers themselves can develop raised spots, which are small at first before turning brown
with a wart-like appearance. As leaf fall is extensive, peppers can become susceptible to
sunscald and reduced yield, with BLS a cause of complete crop failure. This is caused by
bacteria, with a typical cause of infection being infected seed. Once a plant is infected,
transmission can occur from water movement from one infected plant to another e.g. touch-
ing of leaves, splashing of water from overhead feeding etc. Prevention is better than cure,
with care taken to source certified disease-free seed and seedlings; avoid planting in areas
which have tomatoes or peppers planted previously (the same bacteria infects both peppers
and tomatoes); copper sprays can be used effectively to prevent infection.
Beet Curly Top Virus (BCTV)
- this virus transmitted by the beet leafhopper, is
one of the most damaging viruses which affects a range of crops including peppers. As
leafhoppers survive winters from winter annuals such as mustards, BCTV is most severe
in falls and winters with heavy rainfall, which allows for excellent growing of winter an-
nuals. The leafhopper over winters then migrates in to growing areas during the growing
season, spreading the virus as they feed on pepper plants. Seedlings are more dramatically
affected by the virus than older plants, with yellowing, twisting and curling of the leaves.
In severe infections the seedling can die. Stunting is seen in older plants, with curling of
the leaves apparent, which eventually become stiff and leathery. Such infected plants pro-
duce little to no fruit. Prevention is quite difficult given the wide host range of the virus,
with insecticides having been shown to have little impact on infection rates. Shading can
provide some protection in that the leafhopper will not feed in a shady location. Alternat-
ively plants can be covered with a fine mesh to prevent the leafhopper gaining access to
