Nicandra physaloides POTW

Of interest this week at Beal...
Apple of Peru
Nicandra physaloides
W. J. Beal
Botanical Garden
Family: the Tomato family, Solanaceae
Also called Shoo fly plant, Insect repellent plant
The Apple of Peru, Nicandra physaloides, is the only member of its genus. The genus
name, Nicandra, recalls the name of the second century poet Nicander of Colophon.
One of his two surviving works, Alexipharmaca, deals with toxins and poisons of both
animals (e.g., snakes, spiders, and scorpions) and plants. Although some criticize his
parroting of second-hand sources, especially Apollodorus of Alexandria, his packaging
of the information in verses encouraged memorization and made his volumes the standard for toxicology students until the Renaissance. He never actually saw his namesake
plant because he lived in second century Europe and Nicandra is native to Peru.
Apple of Peru is a tender annual that may be easily started from seed and can reach a
height of over a meter. After the first season, they may self-sow so vigorously that they
become an aggressive weed, and they have achieved this weedy status in many of the
temperate and subtropical countries of the world. They are most successful in moist
well-drained soils. There are some recommendations for using the leaves, boiled like
spinach, as human food. However, the reputed toxicity of the plant should militate
against the free-lance experimentation with it in the diet at this time.
An alternate common name, Shoo fly plant, embodies its dubious food chemistry. In
many areas, recalling its common name above, the plant is used as an insect repellent
by simply rubbing exposed skin with the tender stems and foliage. In some communities the plant’s boiled extract is mixed with milk and left out as fly poison; strongly
reminiscent of utilizing the Fly-poison mushroom, Amanita muscaria, also combined
with milk to kill houseflies. In a 1972 paper, Begley, et al., discuss the structures included in the at least 17 compounds that have been identified in aqueous extracts as
inhibiting the feeding of herbivorous insect larvae. In a 2003 paper by authors N. Dimetry and S. El-Gengaihi, six compounds isolated by petroleum ether extraction from
Nicandra physaloides demonstrated the ability to cause mortality in female two-spotted
spider mites. Although these compounds did not affect the mite eggs with which they
came in contact, the ability to affect adult females lasted for at least 7 days. In spite of
Up close, the dark colored “dots” that decorate the adaxial surfaces of the leaves of young plants are seen to be small cuticular
spikes or trichomes giving the Apple of Peru yet another (in addition to its toxins) line of defense against herbivorous insects.
the effects of Nicandra extracts on insects, the plant has been observed to be an alternate host for the important crop-damaging nematode Meloidogyne javanica.
Although the seeds of Apple of Peru have a history in folk medicine, they are generally
regarded to be too toxic for self medication or experimentation.