This belief is based on a complete misunderstanding of plant nutrition and physiology. Plants require inorganic nutrients such as nitrogen, phosphorus and potassium for normal growth. They obtain these elements from the soil and have no mechanism for distinguishing their original source. If adequate amounts are present, plants grow normally. If they are not, this does not occur.
Pesticides are a slightly different matter.
Appropriate safety limits have been established, and some pesticides have been banned. It is possible to grow plants without using pesticides, but yields per acre are much diminished. So one either trusts scientific farmers and the regulatory process or one pays considerably more for food. In Chinese pharmacies, antlers are typically displayed on velvet mats in glass showcases and sold at prices comparable to fine pearls. Deer antler and rhinoceros horn have never been proven to contain any constituent that stimulates libido or cures impotence.