Optimara Growing Tips
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9
• Root Nematodes --
As the name indicates, root nematodes attack the roots of African
Violets. The infestation is recognizable by the light brown lumps on the roots. Growth is also
stunted.
In this case, we recommend to drench with Vydate or Metasystox , i.e., once a week over a three
week period. During the application, the root system should become quite moist in order to
achieve good results.
• Strawberry Nematodes --
The infestation by strawberry nematodes looks similar to
the one caused by mites. However, in contrast to the mite infestation, the young leaves are
heavily deformed and have almost no hair at all. These African Violets grow very slowly and
produce numerous tiny and very hard leaves in the heart of the plant.
This pest can be treated the same way as the leaf nematodes. But in this case we recommend to
spray 3 times within 10 days.
• Thrips (Western Flower Thrips) --
Thrips is currently one of the most unpleasant
pests affecting the African Violet. It is very difficult to get rid off once your crop is infested. The
most obvious indication of thrips is the presence of pollen on the blossoms right under the
anthers. The pest itself can be seen on the anthers and on the calyx. If you touch the anthers
with your fingernail, the thrips appear on the blossoms. Young thrips are about 1/16" long and
white to grey in color. Adult thrips have wings and are yellowish brown.
The treatment against thrips has to be done on a regular basis. A firm preventive spray program
is essential. If you have a very heavy thrip infestation, you should treat the plants 2 times per
week for 4 consecutive weeks. A one-time treatment only does not kill all the thrips. Products that
yield good results are Monitor, Avid or Orthene.
• Mice --
During fall, when it gets colder outside, you can expect the presence of mice in the
greenhouse. If you find anthers that are gnawed off, it is time to do something against these
intruders. Use regular mice controls.
Fungal Protection
The best preventive measures against fungi are absolute hygiene and cleanliness in the
greenhouse. Train your personnel to remove infested plant material and request that they wash
their hands after touching an infested plant before continuing their work with other plants.
Furthermore, make sure that the tables are disinfected before new plant material is placed on the
same spot where the infested plant was removed. Diseased plants are usually identified in time.
Careless handling, however, causes the disease to spread and to get out of control.The major
diseases are outlined below:
• Phytophthora (Crown Rot) --
A sure indication of Phytophthora is the brown rot that
develops first at the plant's base. As the infestation continues, the entire plant starts rotting. Once
