I'm from New Jersey and like to share what I learned about
saving my Broccoli plants from those pests that make
hundreds of holes (large & tiny) in the leaves of the plant.
First off, if you only have a dozen or less plants it's
actually very easy to avoid pesticides and just
hand pick the pests form the plants. I tried both
ways and think it's easier to hand pick them.
Here in NJ, the holes start appearing in the first half
of June. In the daytime, look on the top side of each
leaf and you will likely find little light green worms
resting on the center vein of the leaf. These are
commonly called cabbage worms or cabbage
loopers. They are typically about 1/2 inch to 3/4
inch long and about 1/6 inch in diameter. Those
are the large ones you can easly see but actually
there are more but they are much smaller than that!
After you found a few of the big ones and know what
to look for, focus your attention on each leaf and look
hard because the smaller ones blend in well. Look
all over each leaf on the top and bottom side and you
will find very tiny green worrms as small as 1/8" long
and only about 1/32 inch diameter. They like to hide
right next to the tiny veins on the underside of the
leaves and it's easy to miss them unless you know
what to look for. If you are a newbie, I recommend
using a magnifying glass just until you know what
they look like..
Once you find the worms, you can simply squish them
betwen your finger tips. For the very tiny ones, it's
just easier to quish them right onto the leaf than to
try to pick them up.
Anyway, I found that you only have to pick them off
for a few weeks early in the season and then they
seem to disappear completely for the rest of the
season. I'm not sure if that is unique to my location
so someone else might want to comment on this.
BTW: The reason I posted this long detailed tip
is becasue this topic comes up each year in this
NG and even though I read the posts it took me
several seasons to find out that there were also
the very tiny ones hiding on the undersides of the
leaves. I hope this helps you too! <smile>