These methods are most effective when gypsy moth populations are at low or moderate levels and when only a few trees require protection.
(These methods; are; most effective; T:when gypsy moth populations are at low or moderate levels and when only a few trees require protection) (gypsy moth populations; are; at low or moderate levels) (only a few trees; require; protection)
These methods gypsy moth populations only a few trees
are are require
most effective T:when gypsy moth populations are at low or moderate levels and when only a few trees require protection
at low or moderate levels
protection