In the last few years, growing Lupins, either from seed or vegetatively, has become uncreasingly tricky.
Cause:
Colletotrichum acutatum. This fungal infection is often called Anthracnose and is found worldwide. Many different genera and species can be attacked by this fungus.
Symptoms:
Initial growth often appears good, however once the temperature surpasses 25°C (77°F) the young leaves start to develop a contorted growth showing chlorotic spots. Later this can lead to brown patches and the whole plant may wilt. Lupins planted out in the right location are less susceptible to these problems.
Precautions:
1.) Use Jelitto JET® - heat treated seed. This seed is virtually free of Colletotrichum, although attack from other sources cannot be completely ruled out.
2.) Cultivation tips: we suggest you consider the following suggestions as plants grown hard under ideal conditions are much more resistant to disease.
- Select a well-drained potting medium with a neutral to slightly acid pH. Do NOT use peat or similar potting mediums. A mixture of sandy clay, humus and fine gravel is recommended. Important - fertilize only sparingly and only at the minimum concentration.
- Use only sterilised soil and new or thoroughly sterilised pots.
- Normal seed (non JET®) should be soaked in hot water (30 minutes at 55°C (131°F) to kill any existing spores. This can result in a 10-20% lower rate of germination.
- Lupins should preferrably be grown in the cold season with temperatures under 20°C (68°F) (October - April in Germany).
- Since the infection is not spread by wind but by waterdrops from overhead watering or rain, we recommend using bottom watering or a flood system in a greenhouse. This prevents the foliage becoming wet and spores spreading. Avoid condensation.
3.) Pesticides: we cannot guarantee the effectiveness of any fungicide treatment. Please contact your loval adviser for fungicides. The following are some general points for your attention:
- In the initial stages of the disease, spraying at fortnightly intervals may help, using Baymat fluid (0,15%), active ingredient Bitertanol, or Topas (0,015%), active ingredient Penconazole. In order to test the phytotoxicity it is advisable initially to treat only a very small number of plants. Alternatively it is possible to spray with Euparen (0,125%), active ingredient Dichlofluanid, in the first stages of growing. Sportak (0,1%), active ingredient Prochloraz, can be sprayed during the following stages.
