Agriculture Reference
In-Depth Information
the plant, though taking care that the plant or leaf will not touch the mesh. As the season
progresses, the mesh cage can be removed as the threat of infection lessens.
Cucumber Mosaic Virus - this disease can manifest itself in several different
ways. Typically a fading of the leaf color occurs (pale green to yellow), with ringspot pat-
terns developing. Deformation of leaves is also seen. The severity of the infection is de-
pendent upon the time of infection with infection of younger plants leading to more severe
outcomes (stunting of plants etc.). Peppers can develop ringspotting and roughness, mak-
ing them unmarketable. There is no cure for this disease, though some resistant varieties
are available. Sources of the virus include infected seed, infected weeds and aphid trans-
mission, with floating row covers used to prevent aphids reaching the plants.
Cutworm - cutworm caterpillars can wreak havoc on your plants by eating through
your stems at night. This is evident though plants or seedlings severed right through and
lying on the ground. During the day the caterpillar rests underground and at night emerges
to ground level where they move along the surface feeding on low-lying vegetation. This
can persist for 3-5 weeks, before the caterpillar goes underground to continue its develop-
ment. The caterpillar can be identified as being a thick grey or dark brown color having a
greasy appearance. Prevention is relatively simple. When planting seedlings, wrap a thin
layer of paper (or empty toilet roll holder) around the stem of the plant, making sure this
paper crosses the line of ground level. As this covers the ground level the cutworm will
encounter this and will be unable to eat through it.
Nematodes - nematodes are microscopic worms which live in the soil. The major-
ity of nematodes are beneficial; however a species of nematodes causes a disease known
as root-knot. These knots which form on the roots prevent the roots from effectively taking
up water and nutrients and passing them on to the plant. This can cause stunted growth,
wilting and yellowing leaves. To prevent these there are three main approaches: 1. Use and
plant resistant-strains. 2. Plant a marigold variety such as “Nema-Gone” or “Tangerine”.
These produce a substance which reduces nematodes in the soil. Simply plant marigolds in
the infected area (at a high density) for at least three months, before tilling them in to the
soil. 3. Finally you can solarize your soil i.e. lay transparent plastic sheeting over the moist
soil and secure tightly with stones/bricks. Leave in place for 6-10 weeks of warm sunny
weather to eliminate the nematode population.
Tobacco Mosaic Virus - the first signs of this viral disease is a light green color
which appears between the veins of newer leaves. As the virus spreads, the leaves take on
a mottled or mosaic pattern. Plants can become stunted, leaves curl and yellow with the
peppers becoming infected, causing deformities and reduced yield. There is no cure for
this disease, however resistant varieties are available. The source of this virus is typically
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