PREFACE to 1994 book One of the first responses
that we had to the book Aphids on the
World's Crops, soon after its publication in 1984, was from a colleague
in forest entomology, who pointed out that, despite the title of the work, we
had neglected even to mention a crop that he regarded as rather important,
namely timber. Almost ten years later, we hope that we have now gone some way
towards rectifying that omission. When we compiled Aphids on the World's Crops (1984) we had good reason to turn a
blind eye to the aphids on timber trees, as we knew that keys to identify
tree-dwelling aphids would be a very different task, much more complicated
than the rather simple keys that we put together ten years ago to identify
the aphids most commonly found on agricultural and horticultural crops. When
we actually got down to the job, we found it necessary to adopt a far more
comprehensive approach than in the earlier work, as we could think of no
justifiable reason for including some aphid species and omitting others. There
was also no way of providing keys to identify aphids that had not been slide-mounted,
as many of the key couplets involve relatively minor differences between
closely related species, requiring microscopic examination. We think,
nevertheless, that non-specialist entomologists will be able to use this book
to identify tree-dwelling aphids at least to genus, and it may then be possible
to confirm the identity of a species by taking into account the biological
information provided in Section III. Another small problem was to decide
what is, and what is not, a tree. We claim no
expertise in this matter, and have relied on standard botanical reference
works, especially Bailey (1949), Uphof (1968), Willis (1973), Boutelje (1980)
and Mabberley (1987). If a genus contains plant species classified as trees
by any or all of these authorities then we have included it. If, as is often the
case, the same genus includes species of shrubby habit, then we have also generally
included such shrubs in the host lists because, in choosing a host plant, aphids
have a lot of regard for its genus but very little regard for its growth
habit. We are
grateful to several colleagues who have given permission for the results of
their (as yet) unpublished work to be included; namely B. Agarwala, S.
Akimoto, S. Aoki, S. Barbagallo, P.A. Brown, C.I. Carter, S. Chakrabarti, R.
Danielsson, J. Holman, N. Moran, J.H. Martin, D. Noordam, W. Quednau, G.
Remaudière, J.T. Sorensen, D. Stern, M.B. Stoetzel and D.J. Voegtlin. |