hellebore powder.

"Lice appear on cauliflower. The kerosene emulsion which we use on our
indoor plants is all right for this work, too. The lice appear on the
foliage in great white masses. They suck the life and goodness from the
plant. They come all through the summer at any time. Whale oil soap is
another good spray to use. Peter has typewritten receipts for these
sprays which you may have at the close of this talk. Sometimes the root
of the cauliflower is attacked. Little white maggots mine or burrow
through the root. They are quite likely to begin their bad work in June
or July. That rather dangerous carbon bisulphid is the medicine for this
trouble. Make a hole in the soil as you did when treating the ant. Do
not make this too near the plant. I should say six inches away would be
about right. Pour a teaspoonful of the poison into the hole and it will
take care of itself. Cover the hole over as you would in the case of the
ant. When cauliflower plants begin to look sickly pull one up. If it is
full of maggots that is easy to determine. But it may be that you will
find great lumps or knots on the root. Since these knots appear during
the same months as the maggots, you can only be sure of the real cause
by pulling up a plant. If these knots are on the root, then you have a
very serious trouble to contend with. So serious is the club root
condition that the only safe thing to do is to pull up and completely
destroy the diseased plants. Dig the soil up after this. Then lime it.
Put a lot of lime on, not just a dusting over the surface of the soil.
This represents soil that is in trouble, so do not plant cauliflower
here again, or its coarser cousin, the cabbage.

"Sometimes a little red or orange and black bug appears. This is called
the harlequin bug from its fantastic appearance. This bug may come all
summer long at any time. The whale oil soap spray is the one to use.