from bed to bed. At every fresh transplanting the
mycelium exerts itself into renewed growth, for it must become a strong
plant before it has strength enough to produce and support a mushroom.
Our utmost efforts have never rendered mycelium in a mushroom-bearing
condition perennial.

CHAPTER XIX.

INSECT AND OTHER ENEMIES.

The mushroom grower has his full share of insects to contend with, and
in order to overcome them one should acquaint himself with them, and
know what they are, what they do, whence they came, and how to destroy
them. One should study the diseases and mishaps of his crop and endeavor
to know their cause. If we know the cause of failing health in plants,
even in mushrooms, we can probably stop or devise a remedy for the
disease or means to prevent its recurrence, and if we can not benefit
the present subject we are forewarned against future attacks. But there
is a deal of mysterious trouble in this direction in mushroom-growing.
We are likely to know something about the depredations committed by
insects or parasitic molds above ground, but I am sure there is a good
deal of mischief going on under ground of which we know very little, if
anything. The ills to which the mycelium is subject are not at all fully
understood.

="Maggots."=--This is the common name among practical mushroom growers
for the larvae of a species of fly (Diptera) which from April on through
the warm summer months renders mushroom-growing unprofitable. It is
unavoidable, and so far has proved invincible. It attacks the mushrooms
in deep cellars, above-ground houses, greenhouses, or frames, and is
often quite common in early appearing crops in the open fields. We
sometimes read that it does not occur in unheated cellars, but this is a
mistake, for in our unheated tunnel cellars, where the temperature in
April does not exceed 55 deg., maggots always appear about the end of this
month. But it is true that in the case of cool houses and where the beds
are covered over with hay or straw maggots do not appear as early in the
season as they do in warm houses and open beds. While rigid cleanliness,
and care in keeping the house or cellar closed, no doubt have much to do
in lessening the trouble, I have never been able to overcome it, and
know of no one who has. We simply stop growing mushrooms in summer.

The maggots or larvae are about three-sixteenths to four-sixteenths of an
inch long, white with black head, and appear in al