der off and die. When a grub
dies, it multiplies the number of spores up to many millions. That
portion of soil becomes infective, and more grubs going through the
infective portions carry the disease to intervening areas until the
whole piece of turf is unhealthful to these grubs. Droppings of birds
feeding on sick grubs spread the disease.

MR. FRYE: One application is all that's needed?

DR. ADAMS: One application is all that's needed. Control is slight at
first, but increases with the passage of the years.

MR. CORSAN: Quail feed on them. Why can't we have quail around the farms
instead of shooting them?

DR. ADAMS: I would be for that, but we have to find other methods for a
lot of people. Besides, we need something that will intercept some of
the grubs in the fall, before they get big. After all, by the time the
quail are interested in them, they have already done some damage in the
ground. In the ground the grubs can do two kinds of damage. They can
make turf loose so it can be rolled back like a rug. Second, if you
should plow up a piece of sod that has many grubs in it and try to plant
row crops or nursery stock, they may eat the roots off the planting in
the spring.

DR. McKAY: I'd like to ask what effect low temperature has on them and
how far north you think will be their limit?

DR. ADAMS: The soil temperature at which the grubs begin to die in
hibernation is 15 degrees, and I have never seen the soil temperature
that low here under turf. (I operate a soil thermograph on my lawn.)

A MEMBER: How far down do they go?

DR. ADAMS: They hibernate at 4 to 8 inches in the ground. It's rare to
have it drop below 27 degrees at these depths.

MR. STERLING SMITH: What do you mean, Fahrenheit?

DR. ADAMS: That is Fahrenheit.

A MEMBER: That's frozen solid. That's at 32 degrees.

DR. ADAMS: The deeper soil will drop only a few degrees below freezing.
The soil here usually remains no lower than 32 degrees, except within an
inch or two of the top.

A MEMBER: Do you think soil temperature is going to be a limiting
factor?

DR. ADAMS: I think the limiting factor northward is the coolness of the
summers. In Northern Japan their life history gets altered because of
the shortness of the summer, and I think in the Adirondack area they
won't be serious for that reason.

MR. WEBER: Will this spore powder kill other kinds of grubs that are in
the sod?

DR. ADAMS: Not to any practical extent. It does not contr