are large enough for them to attack and very
often considerable killing back of the terminal growth occurs. I have
seen it on English walnut seedlings in nursery rows where there would be
very large kill-back from the walnut curculio. Superficially the injury
on the fruit is quite similar to that of the husk maggot.

(First slide.) This first slide is just to give you some idea of the
general areas of fruit growing and distribution in New York State. The
eastern section, right-hand side, Champlain Valley and Hudson Valley,
are primarily apple maggot regions. Some walnut husk fly probably occurs
there, but they are predominantly apple-growing areas. In the central
part of the state, northern, particularly, we have fruit, and as far as
I know, there are no plantings of walnuts there, though you people may
know of some. In The Ontario Plains section south of Lake Ontario is one
of our big fruit belts in the State. Some walnuts are also grown here.
Consequently this area has in it apple, walnut and cherry maggot flies,
and, of course, they will be lapping over in all those areas into
surrounding territories. But this gives you an idea, in a general way,
of the distribution of the host plants and the flies about which I have
been speaking.

(Next slide.) Those flies get pretty big when you get them up there.
They are not that easy to see in the field. The ones on the top are the
species found on cherries. The one on the lower left is the apple
maggot, the one on the lower right is walnut husk maggot. The only
difference you can see here is in the wing pattern but in nature they
differ in color. They all have a little different wing pattern. Also,
there is a little difference in size, the walnut husk maggot being the
biggest of the four species shown here.

(Next slide.) I have shown here the emergence date of the various
species, including the cherry fruit flies, the apple maggot and the
walnut husk fly. And you notice that beginning over about the first week
in June you have emergence of the cherry fruit flies, and you have a
continuance of emergence of some of these species up until at least the
first or second week in August. These points going up and down just show
the number of flies that were taken on given dates, and there is a very
definite correlation between the proportion of flies that emerge on any
given day with the temperature or moisture condition. Some years, when
you have very hot, dry weather, there is c