Russian-born botanist and plantation manager. Krukoff mounted eight major expeditions to South America and Africa between 1928 and 1955, working chiefly to develop new drugs with Merck & Co. He discovered more than 200 species and also ran plantations in Central America. Boris Krukoff gave two different accounts of his early life, either saying he was born in Minusinsk in the Siberian province of Krasnoyarsk or in Kasan on the Volga river. His father, also a botanist, lived in Kasan and made a collection of specimens for the herbarium in Minusinsk.

In 1917, when Krukoff was 19, he entered university in Kasan. However, the Russian Revolution also took place at this time and rather than studying over the following years, he served in the military, fighting the Bolsheviks. He joined the Russian Navy and Marine Corps and in 1919 was captured by the Red Army while on a reconnaissance mission. The experience would prove to serve him well in his later career, which involved several instances of industrial espionage and smuggling of botanic material. Making his escape, he rejoined his allies and departed from Vladivostok with the Siberian Flotilla in 1922, which on arrival in the Philippines was interned and its personnel transported by the U.S. Navy to San Francisco. Krukoff, however, reported that he somehow avoided this destination and spent the next two years travelling elsewhere, finally arriving in the United States in 1925.

After studying English and working in menial jobs for some time, he enrolled at Syracuse University, New York. He graduated from the Syracuse College of Forestry in 1928 and obtained work with the Intercontinental Rubber Company, who sent him twice to Brazil to research nuts yielding edible oils (he does not seem to have collected botanical specimens at this time). The remainder of his time was spent working with the cultivation of Parthenium argentatum (common name guayule), a source of latex. He took two breaks from work to venture on his first plant collecting trips to Africa and Sumatra (1930-31). A third trip to the Amazon followed (1931-32), which Krukoff carried out on behalf of the New York Botanical Garden and pharmaceutical company, G.W. Cole, and secretly for the U.S. Rubber Company as an industrial spy. He collected Hevea brasiliensis seeds and wrote a detailed report on the Ford Motor Company's plantations near Boa Vista in Brazil for the latter.

Krukoff had barely set foot back on U.S. soil than he was on another expedition, returning to Sumatra in 1932-33 to deliver plants to the U.S. Rubber Plantation in Kisaran province. While in Sumatra he collected hundreds of specimens to sell to herbaria and also picked up bulbs of Amorphophallus titanum, famed for its huge, foul-smelling inflorescence, intending to sell them in the U.S., Europe and elsewhere. The restless Krukoff set off on three more Amazonian expeditions before 1936, during which time he worked for Caffco Drugs. Employing him as a botanical consultant, Merck & Co. sent him to Bolivia in 1939 to collect seeds of Cinchona calisaya for quinine production. The seeds had to be smuggled back to the U.S. because it was illegal to export them. Merck then sent Krukoff to Trinidad, British Guiana (now Guyana) and Suriname in 1942 to collect Ryania, a plant insecticide, and he was also brought in on projects to seek out alternative anti-malarials and cortisone. His involvement in the latter project in 1949 included what effectively became a wild goose chase to collect seeds of Strophanthus species from West Africa. After spending a fortune on Krukoff's expeditions and research, his employers reverted to producing cortisone from the raw material they had previously been using, ox bile.

The 1940s also saw Krukoff appointed General Manager of Experimental Plantations, a subsidiary of Merck concerned with growing Cinchona (and later coffee) in Guatemala and Costa Rica, and honorary curator at New York Botanical Garden. He married Florence V. Barry (Flo) in 1945, who managed the finca in El Naranjo, Guatemala, that he had purchased for Merck's first Cinchona plantation. These assets, however, did not effectively contribute to Merck's drug business, so they were sold at a cut-down price to the Krukoffs in 1960. Boris and Flo ran the plantations profitably and built up considerable wealth.

The latter part of Krukoff's life was spent on taxonomic research and supporting research projects at institutions including New York and Missouri, both of which he endowed along with Kew and Leiden. He would visit herbaria in Europe and South America annually in the 1970s, researching his two favourite genera, Strychnos and Erythrina. He remarried in 1975 (to Ruth Hodgins) after Flo Krukoff died of cancer. Friends and associates described his character as determined, often critical, but very loyal, and extraordinarily thorough in his work. A fanatical organiser, Krukoff kept files on all of his activities, from a list of his classmates' names to every memo and piece of correspondence related to a project. On his expeditions from the 1920s to 1950s, he collected some 11,000 specimens and 4,000 wood samples for herbaria and wrote more than 70 papers on economic botany and taxonomy.