Early leaf spot, caused by Cercospora arachidicola, and late leaf spot
, caused by Cercosporidium personatum, can be controlled by foliar fun
gicides. Extension recommendations in South Carolina suggest planting
peanuts between 15 April and 15 May. The recommended starting date to
initiate 10- to 14-day fungicide spray schedules to control leaf spot
is 15 June. The 1980-1990 climatological data for Sumter, Florence, an
d Blackville, South Carolina, were used to simulate calendar spray sch
edules and a method for spray timing developed at Auburn University (A
UPNUT) that used observed and forecast rainfall, This simulation showe
d that adoption of AUPNUT scheduling in South Carolina could result in
less foliar fungicide usage than the 10- and 14-day calendar-based sp
ray schedules. The study showed: (i) the number of AUPNUT sprays depen
ded on location in the state; (ii) the AUPNUT schedule added one appli
cation prior to 15 June on early-planted fields but averaged less than
one additional spray per year for later plantings when compared to a
14-day calendar-based schedule that started on 15 June; (iii) at least
one spray per year can be saved regardless of planting time, and up t
o five sprays can be saved depending on the distribution of days with
rain; and (iv) a simulation using historical weather data can demonstr
ate potential savings associated with adoption of new application sche
dules.