Making friends
The American
raspberry interacts with many other organisms. Some of these
organisms are harmful to the raspberry and others aid the
raspberry in things it cant do on its own.
Caterpillars: Caterpillars can be
very harmful to the raspberry plant or any plant that you happen
to have in your garden. The caterpillars can be highly
destructive
to the raspberry plant by eating away the leaves and some of the
stem. This is harmful to the raspberry plant because it
decreases the amount of surface area for photosynthesis and harms
the stem. To avoid having caterpillars take over your raspberry
bushes keep the weeds, such as
dandelions, down in the garden and remove caterpillars
from any leaves of stems that you may see. Some insecticides may
be used to keep the caterpillars out or garden specific plastic
wrap may also be used.
Verticillium Wilt:
Verticillium wilt is one of the most
serious diseases of raspberries. It is caused by a fungus in the
soil which reduces the raspberries yields by
wilting
and stunting, and eventually, killing the fruit or the plant all
together. The fungus which causes this is
Verticillium albo-atrum and had been known to infected more
than 160 different kinds of plants. This fungus can survive
within the soil for many years. The hyphae of this fungus
penetrate the root directly of the plant that it is infecting.
From there, the fungus grows into the xylem, the water
conducting tissue, and this destruction of the water column
prevents the movement of water up to other tissues of the plant
and the plant dies. This disease usually is worse in black
raspberries than red raspberries. This disease is usually a
cooler weather disease and is most severe where there is poorly
drained soil and continuously flowing cold, wet springs.
The symptoms of this disease usually appear in July or early
August. The lower leaves may appear to have a dull green cast to
them as compared to the brighter leaves higher on the stem. The
disease starts at the base and moves its way up the stem. The
last effects of the disease are noticed on fruiting cranes that
were infected the year before, because in the spring, many of
the diseased cranes will be dead. If the crane is not dead, then
it will most likely appear poorly developed and/or have
shriveled buds. The new leaves that grow the following year
after the plant has been infected are usually yellow and have
stunted growth.
Fungicides are ineffective in control against this fungus. Soil
fumigation has shown to be excellent in control but can be very
expensive.
Birds: Birds are also a big fan of
raspberries, and if people are not careful, they may be
sharing their harvest with more than they thought. They will fly
over and stop for a quick meal. This can be very frustrating for
a raspberry patch owner, so many of them use nets to keep the
birds out.