222
Gene R. DeFoliart
SR 10 against Ae. melanimon, but against C. tarsalis dosages as high as 0.2 lb/
acre gave unsatisfactory control of all instars including the fourth.
Slow-release fonnulations have greatly increased the potential efficacy of
juvenoids and other IGRs. Dunn and Strong (1973) reported that polyurethane
wafers of 3% methoprene content (by weight) gave a high degree of control of
C. pipiens in catch basins for more than 53 days following application of a wafer.
Against C. pipiens in sewage water, Hoppe et al. (1974) found that 1 ppm
methoprene gave 93% inhibition of adult emergence when applied as a granular
fonnulation at 3-week intervals. By contrast, only 55% inhibition of emergence
was obtained when methoprene was applied as an emulsifiable concentrate.
Rathburn and Boike (1977) found that methoprene briquets were almost completely effective against Ae. taeniorhynchus for 31 days after initial application,
while a black sand granular fonnulation applied at 0.01 lb/acre had no residual
activity 7 days after application. When exposed 21 days as a preflood application,
the briquets displayed complete residual effectiveness for at least 7 days after
flooding (later tests were not made).
Case and Washino (1978) tested two fonnulations of met hop rene, the standard microencapsulated fonn, and a IOF charcoal fonnulation against C. tarsalis
in California rice fields. The insecticide was applied aerially at the rate of 0.1
lb/acre. By the 7th day posttreatment, emergence rates in treated fields were not
significantly different from those before treatment began. Failure to achieve
better control was attributed to water flow through the test plots and the asynchronous age structure of C. tarsalis populations.
Self et al. (1978) compared diflubenzuron (TH-6040) (= Dimilin@) [25%
wettable powder (WP)] and methoprene (= Altosid® IOF briquette fonnulation)
against C. quinquefasciatus in Jakarta, Indonesia. At a dosage of 1 ppm, the
compounds were highly effective in preventing adult emergence for 2 and 5
weeks, respectively, after one application.
Early work with diflubenzuron, a urea-type compound that inhibits chitin
fonnation, has yielded impressive results. Mulla et al. (1974) tested EC and WP
fonnulations against asynchronous field populations of C. tarsalis and found
them equally effective, producing high to complete inhibition of adult emergence
for 5-15 days posttreatment. In subsequent tests in which the material was
applied at 0.025 and 0.05 lb/acre against C. tarsalis in ponds, adult emergence
from treated larvae held in floating units was almost completely inhibited for at
least 11 days posttreatment (Mull a et al., 1975). Against third instar Ps. columbiae in rice plots, Steelman et al., (1975) found that diflubenzuron provided
100% control 24 hr posttreatment at the lowest dosage tested, 0.001 lb/acre.
Methoprene, by comparison, provided 100% control at dosages as low as 0.05
lb/acre but only 40% at 0.001 lb/acre. Finally, Mulla and Darwazeh (1976)
reported complete control of the synchronous floodwater mosquito, P s. confinnis,
in irrigated alfalfa hay fields and complete inhibition of emergence for more than
Gene R. DeFoliart
SR 10 against Ae. melanimon, but against C. tarsalis dosages as high as 0.2 lb/
acre gave unsatisfactory control of all instars including the fourth.
Slow-release fonnulations have greatly increased the potential efficacy of
juvenoids and other IGRs. Dunn and Strong (1973) reported that polyurethane
wafers of 3% methoprene content (by weight) gave a high degree of control of
C. pipiens in catch basins for more than 53 days following application of a wafer.
Against C. pipiens in sewage water, Hoppe et al. (1974) found that 1 ppm
methoprene gave 93% inhibition of adult emergence when applied as a granular
fonnulation at 3-week intervals. By contrast, only 55% inhibition of emergence
was obtained when methoprene was applied as an emulsifiable concentrate.
Rathburn and Boike (1977) found that methoprene briquets were almost completely effective against Ae. taeniorhynchus for 31 days after initial application,
while a black sand granular fonnulation applied at 0.01 lb/acre had no residual
activity 7 days after application. When exposed 21 days as a preflood application,
the briquets displayed complete residual effectiveness for at least 7 days after
flooding (later tests were not made).
Case and Washino (1978) tested two fonnulations of met hop rene, the standard microencapsulated fonn, and a IOF charcoal fonnulation against C. tarsalis
in California rice fields. The insecticide was applied aerially at the rate of 0.1
lb/acre. By the 7th day posttreatment, emergence rates in treated fields were not
significantly different from those before treatment began. Failure to achieve
better control was attributed to water flow through the test plots and the asynchronous age structure of C. tarsalis populations.
Self et al. (1978) compared diflubenzuron (TH-6040) (= Dimilin@) [25%
wettable powder (WP)] and methoprene (= Altosid® IOF briquette fonnulation)
against C. quinquefasciatus in Jakarta, Indonesia. At a dosage of 1 ppm, the
compounds were highly effective in preventing adult emergence for 2 and 5
weeks, respectively, after one application.
Early work with diflubenzuron, a urea-type compound that inhibits chitin
fonnation, has yielded impressive results. Mulla et al. (1974) tested EC and WP
fonnulations against asynchronous field populations of C. tarsalis and found
them equally effective, producing high to complete inhibition of adult emergence
for 5-15 days posttreatment. In subsequent tests in which the material was
applied at 0.025 and 0.05 lb/acre against C. tarsalis in ponds, adult emergence
from treated larvae held in floating units was almost completely inhibited for at
least 11 days posttreatment (Mull a et al., 1975). Against third instar Ps. columbiae in rice plots, Steelman et al., (1975) found that diflubenzuron provided
100% control 24 hr posttreatment at the lowest dosage tested, 0.001 lb/acre.
Methoprene, by comparison, provided 100% control at dosages as low as 0.05
lb/acre but only 40% at 0.001 lb/acre. Finally, Mulla and Darwazeh (1976)
reported complete control of the synchronous floodwater mosquito, P s. confinnis,
in irrigated alfalfa hay fields and complete inhibition of emergence for more than