Chinaberry tree leaves repel pests because they're toxic.
We drove out in the country and found an abandoned house with a very large old chinaberry tree and got as many leafy fronds as we could reach. We took them home and, since we lived in an apartment that was part of a house, we overlapped the fronds along the base of the outside walls of our apartment, along the edges of our sidewalk, on the outside edges of our steps, and across our threshold. We had no more flea problems at our place.
Much later, I was living in Auburn, Alabama and transplanted a young chinaberry tree in my yard. It quickly grew to about 12 feet high. If our dog got a flea problem, I would pull off a bunch of fronds, strip the leafy parts from the center stem, put them in the blender with water, and blend until I had a thin slurry. I would strain it, take my green liquid and the dog outside, take off his collar and wet him all over except for his face. As soon as the chinaberry juice was on him, the fleas started jumping off. I would let him stand--green and wet--for five minutes (he was a very obedient dog), then take him in and bathe him with people shampoo. There would be a lot of dead fleas, and I usually only did it once or twice a summer (if at all).
I don't know what is in chinaberry leaves, but it's definitely a flea deterrent. I know the fruit is toxic.
In retrospect, that's probably why many old Alabama home sites had very large chinaberry trees in the yard. People used to keep a lot of hunting dogs and I don't remember there being a flea problem, even with many dogs.--Gail Fitzgerald, Virginia
After a little research, I found the reason chinaberry leaves work so well is because they're poisonous. Here's what I found:
Brief description: Pinnately divided leaves and toothed or lobed leaflets. The purple flowers and the yellow wrinkled, rounded berries are borne in terminal clusters.
Poisonous parts: Berries, bark, flowers, and leaves.
Poisoning: Primary effects are gastrointestinal (vomiting and diarrhea). Irregular breathing and respiratory distress are also common. Stomach irritation, vomiting, bloody diarrhea, and paralysis. Toxic only if eaten in large quantities.
Chinaberry (Melia azedarach) is a fast-growing tree which is naturalized in the southeastern U.S. It is invading the forests, fencelines and disturbed areas of Florida and elsewhere, including Hawaii. Belonging to the mahogany family of plants, chinaberry is native to Asia. Striking and colorful, chinaberry was widely introduced as an ornamental shade tree because of its large compound leaves, its distinctive clusters of lilac-colored flowers and its round yellow fruits. Its seeds are spread by fruit-eating birds.
Although it is revered for its beauty in its native range and is used for its medicinal properties, chinaberry's fast-growth and rapidly spreading thickets make it a significant pest plant in the U.S. (Even so, it continues to be sold through nurseries.) Chinaberry outgrows, shades-out and displaces native vegetation; its bark, leaves and seeds are poisonous to farm and domestic animals. Research shows chinaberry to have insecticidal, anti-viral and possible anti-cancer properties. At least one European company makes flooring from chinaberry wood.
Chinaberry is a deciduous, wide-spreading tree which grows up to 50 feet tall, or it may be shrubby. Chinaberry thrives in a variety of soils, and is cold-hardy and drought-resistant. Its leaves are large (up to two feet long) and double-compound (having leaflets on leaflets).
The mildly fragrant chinaberry flowers are small and lilac-colored, with five petals surrounding a purple tube. The flowers occur in showy clusters at the ends of branches.
Chinaberry fruit are round berries, changing from green to yellow, hanging from long stalks; the fruit eventually becoming brownish leathery seed capsules. The capsules will hang from the tree throughout the leafless winter months.--Sources: http://aquat1.ifas. ufl.edu/melaze.html, and www. pharmacy.arizona.edu/centers/apdic/ plants/chinaberry.html: Chinaberry Tree (Melia azedarach)