Solanum nigrum (black morel, petty morel, garden nightshade). A member
of the family SOLANACEAE. Small, much branched bushy annual plant, with dull green
foliage and oval stalked leaves. Angled hollow bearing clusters of white flowers,
succeeded by small green round fruit, ripening into shiny black berries. Very common
wild plant, especially in cultivated soils.
Animals most affected
Cattle, (sheep, goats, pigs, poultry).
Ingestion of contaminated hay, particularly (maize) silage.
Note:the plant has become increasingly resistant to the herbicides used on cultivated
corn (such as atrazine and simazine). This resistance is currently a major problem,
endemic in many areas of France.
The growing plant is unappetizing to eat due to its bitter taste and unpleasant odour.
Contains glucoalkaloids such as alphasolanine and solanidine. Toxicity varies considerably
according to prevailing soil conditions and stage in growth, making toxic doses difficult
to quantify. Maximal plant toxicity is reached when the berries are green (i.e. unripe);
poisoning occurs when ingestion takes place over a prolonged period, especially if
maize silage is badly contaminated (more than I ~l 5% fresh weight). Similar effects
result if the green berries are ingested over a prolonged period.
reduced appetite, drop in lactation;
moderately severe digestive problems:
neurological effects: weakness, lassitude, prostration, motor incoordination;
tachycardia and tachypnoea.
No antidote. Symptomatic care only:
adsorbents (activated vegetable charcoal);
In order to make use of highly contaminated (where the percentage content of black
nightshade is equal to or more than 10% of fresh plant weight):
do not feed to juvenile or lactating animals;
do not include more than 20 kg/day of the silage where contamination reaches
10%; or more than 10 kg/day if contamination is 20%;
alternate feeding the contaminated silage with non-contaminated silage (alternating
every 10-15 days);
carefully monitor the animals for any clinical signs (such as gastrointestinal
problems or abnormal gait).