NPV or Gypchek NPV stands for nucleopolyhedrosis virus. It is a
virus that occurs naturally wherever gypsy moth is present.
Gypchek is a biological pesticide product we use that contains
NPV. This insecticide only infects gypsy moth caterpillars. When
gypsy moth caterpillars ingest leaves with NPV, it stops eating
and dies within a week to 14 days. Only one application of NPV
is needed. When will NPV spraying begin? We usually begin
spraying NPV in southern Wisconsin in May and move northward,
finishing in early June. Planes take off at sunrise. In urban
areas during the school year, we will not spray between 7:15 and
8:30 a.m. Why must planes spray so early in the day? We need the
high humidity and low winds of early morning to assure the spray
does not evaporate or blow away. The planes continue spraying as
weather conditions allow and/or when the area is finished. This
may mean spraying into the late morning or afternoon, if
possible. Is NPV harmful to humans? Numerous laboratory and
field studies over the