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natural enemies of your pests. Punish boys who catch bats or steal eggs from
the nests of birds of prey; divert their energies by paying them a guilder or
two for every hectolitre of cockchafers they can catch. Then feed those dead
beetles to the pigs, or the chickens, or use them to make fertilizer. It’s the same
lesson every time: eat – or be eaten.
To help the farmers in their struggle, Ritzema Bos wrote textbooks, which
he prepared for them and with them. ‘Reader!’ he urged: ‘Write to me about
your experiences, in different parts of our country and on different soils! It is
of the utmost importance.’ 10
His output of textbooks is impressive. Five years after gaining his PhD, in
1874, with a dissertation on the ‘Crustacea hedriophthalmata’ of the Netherlands,
Ritzema Bos published the fi rst volume of his textbook on pests and benefi cial
creatures in agriculture, Landbouwdierkunde. Nuttige en schadelijke dieren van Nederland,
at the age of twenty-nine. Volume 2 appeared in 1882. A year later he
published a book on insect pests, Insectenschade op bouw- en weiland, followed a
year later by a textbook of zoology, Leerboek der dierkunde, the fi rst edition of
which appeared in 1884, and the 15th, posthumously, in 1939. In between times
he also published several other books on related themes: De dierlijke parasieten
van den mensch en de huisdieren (1888); Ziekten en beschadigingen der landbouwgewassen
(four volumes, 5 editions); Ziekten en beschadigingen der ooftbomen (four volumes);
Ziekten en beschadigingen der kultuurgewassen (two volumes). They are all easy to
use; books that readers with little education could pore over at the kitchen table
in the evening, or in extreme cases standing in the mud, looking at individual
crops to discover what might be wrong and how it could be remedied.
Besides producing these books, Ritzema Bos studied numerous specifi c diseases
and infestations. At the request of Jacob Krelage and the General Bulbgrowers’
Association, he launched a study of the narcissus bulb fl y and methods
of controlling its population at the beginning of 1880. He exchanged experiences
with Jan Hendrik Wakker, who was researching yellow disease in hyacinths
at the same time and at the request of the same organization. 11 Once he had
been admitted to this select gentlemen’s club, new initiatives soon followed.
Again at the invitation of Jacob Krelage, and this time collaborating with
Hugo de Vries and several of the country’s other leading botanists, he joined
the Scientifi c Committee of the Dutch Society of Horticulture and Botany in
1889. 12 In 1890 he and Hugo de Vries visited the International Congress of
10 J. Ritzema Bos, ‘Aardappelschurft en hare bestrijding’, Tijdschrift over Plantenziekten, 1924, pp. 12-13.
11 The relevant correspondence can be found in the library of the kavb, Hillegom.
12 This Committee was formed at the instigation of Jacob Krelage, the idea being to promote the
mutual exchange of ideas and information between scientists and farmers. Members of the Society
could send the Committee specimens of striking anomalies in their crops and ask for its expert
opinion. They could also request advice on plant diseases.
34 phytopathology: a private or a public institute?