616
JounNu,oF THEArrlpnlclNMoseurro CourRor,AssocretroN
Vor..7, No. 4
ACTIVITY OF NEW FORMULATIONSOF METHOPRENEAGAINST
MIDGES (DIPTERA: CHIRONOMIDAE)IN EXPERIMENTAL PONDS
ARSHAD ALI
Uniuersity of Florida, IFAS, Central Florida Researchand.Education Center,2700 East CeIeryAuenu.e,
Sanford, FL 32771-9608
ABSTRACT. The IGR, methoprene,in 3 solid (Altosid@
Pellet, Altosid(D
XR Briquet and a granular)
an-da liquid formulation (A.L.L.) was evaluated against chironomid midges in experimental po"ds. The
A
A.!.L.
. L . L . was
w a s applied
(0.015
a p p l i e d aat0.293liters/ha
t 0 . 2 9/o3uLcfs/rla
l i t e r s / h a \u.uro
(0.28
( 0 . 2 8 Kg
granules,
{ 0 . 0 1 5Kg
k g Ar/
kg
A I l [ rra,
Allha)
a ) alu
a n d aL
and
a t 0..'()
at
5 . 8 6 IIIeIS/na
5.86
l i t e r s / h a \u.zd
liters/hi
granules,
k s Arlna/,
kt
A l l h a ) . The
Allha).
Tr hne
e gra
pellets
pelletsand
and briquetswereappliedat 13 kglha
(0.22ke
kelha (0.17kg
ke Allha),
AI/ha),5.6
[a), 5.6 kglha
kelha (0.22kg
rc.22ks.AI/ha) and onebriquet/
briouet/
br
8 m' (0.82 kg Al/ha). respeilively.
rectivelv.The
The low
l6w rate
rate of
of A.L.L. was ineffective,
ineffective.but
hut the high
hish rate produced
nrodrrcr 84100% control of Tanytarsini and 30-100% of Chironomini during 2 wk posttreatrnent. The granular
formulation gave 6l-87% control of total midges in 2 wk posttreatment. Altosid Peilets eave initial and
prolonged good control of Tanytarsini (64-99qo for 7 wli). Chironomini (79-94qo for i wk) and total
midges (64-98% for 7 wk). The briquets at almost 4x the rate of pellets, yielded 38-98% control of
midges for 7 wk posttreatment. Altosid Pellets have an excellent potential for midge control.
INTRODUCTION
Mulla et al. 1971,AIi and Mulla 1978,Johnson
and Mulla 1981).
In recent years, numerous natural or manMethoprene, a juvenile hormone analogue,
made lentic and lotic habitats in urban and was effective against midges in the laboratory
suburban areasexposedto intensive human use and field (Mulla et al. t974, 1976).Methoprene
(residential,recreational,agricultural, etc.) in may have goodpotential for midgecontrol, pardifferent parts of the world are becoming inticularly against OP-resistant midges,but until
creasingly eutrophic. Many of these habitats recently there has been little interest by the
also receivedischargesfrom point and nonpoint industry to developthis IGR for midge control.
sources.As a consequence,macrofaunal species This may have been due to the lack of practical
diversity in these habitats is gradually decreas- and cost-effective formulations of methoprene,
ing and results in the survival and profusebreed- particularly suited for the control of benthic
ing of morepollution-toleranttype of organisms, midges. Recently, three solid formulations of
such as some speciesof Chironomidaewhich methoprenewere developedby ZoeconCorpoconstitute a major componentof the macroin- ration, Dallas, TX, and made available for testvertebrates(Ali 1991).Man-made lakes devel- ing against midges. These formulations, along
oped more recently for residential and recrea- with an existing liquid formulation of the IGR,
tional purposes, in the sunbelt region of the were evaluatedfor their efficacy against natural
southern United States, are particularly well midge populations in experimental ponds in
suited for midges and support denselarval pop- Florida.
ulations (Mulla 1974,Ali and Mulla 1977,Ali et
al. 1978). Adult midges frequently emerge in
MATERIALS AND METIIODS
large numbers, causing a variety of nuisance,
economic and occasionally medical (allergies)
The ponds employedin this study are located
problems for humans residing or working near at the University of Florida's Central Florida
the midgebreedingsources.Ali (1991)has pro- Research and Education Center at Sanford.
vided a detailedreview ofthe variety of problems Each artificial earthen pond is 6 x 4 m and is
posedby adult midges.
filled with water to a depth of 45-50 cm. The
The organophosphate(OP) larvicide, teme- water supply to each pond is from an underphos, is the only chemical registeredfor aquatic ground artesian source,with desiredwater depth
midge control in the USA. The benzoylpheny- maintained by a float valve.
On April 27, 7990,Altosid@Liquid Larvicide
lurea insect growth regulator (IGR), diflubenzuron, is also registered for midge control, but (A.L.L.), Altosid@Pellets, Altosid@XR (exonly in California under a special local need tended residual) Briquets and an experimental
(24c).At present,there is an urgencyto increase granular formulation of methoprene (SAN 810
the number of available options for midge con- I 1.3 GR) were applied to the ponds. Each solid
trol in the USA. In many situations, midge formulation was applied at one rate to 3 ponds
larvae have developed tolerance to temephos. (replicates).The A.L.L. was applied at 2 rates
There is also evidenceof cross-resistanceto the with 3 ponds receiving each rate. Three ponds
OP insecticides(Pelsueand McFarland 1971, were left untreated as controls. Thus, a total of
DncrN,rsen1991
Nrw
FoRlaur,ATIoNS oF METHoPRENE
18 ponds were utilized in this experiment. The
ponds were treated in a randomized block design. To apply A.L.L., the required amounts
were mixed with water in 6 separate 0.5 liter
squeezebottles, each containing 300 ml water,
and applied evenly to the pond surface. The
amount of granules needed in each pond were
mixed with 0.5 kg of sterile,clean sand,and the
mixture was dispersed evenly over the pond
surface.Similarly, the pellets for eachpond were
mixed with 0.5 kg of blank pellets (no active
ingredient) and evenly dispersedover the pond.
Three XR Briquets were placed along the long
axis of each pond, 1, 2 and 3 m from the bank.
The test formulations, percentage of active
ingredient(AI), applicationrates and AI equivalents/ha are summarized in Table 1. All formulations contained the active isomer, (S)methoprene,of methoprene.
Immediately prior to the treatments and at
weekly or twice weekly intervals after treatments, one night's emergenceof adult chironomids from the treated and control ponds was
assessed.The adult emergencefrom each pond
was sampled with a 30-cm high, metal-cone,
submergedemergencetrap (Ali 1980) covering
0.25 m' of the pond bottom. Two cones were
employedin each pond. The water temperature
was measured daily during the experiment by
using a maximum-minimum thermometer
placed permanently in the middle of one pond.
The trapped adults were identified and
counted in the laboratory. Suppressionor inhibition of midge emergencedue to the treatments
was calculatedby the formula given in Mulla et
al. (1971).This formula has provisionsfor adjusting reductionsin the treated areasin relation
to any simultaneous increases or decreasesof
populations in the controls. The pre- and posttreatment midgepopulation data were compared
by analysis of variance. The data were transformedto y' : Iog (y + 1) (Elliott 1977)prior to
analysis, because their frequency distribution
was highly skewedto the left, reflecting numerous zero counts.
6t7
RESULTS AND DISCUSSION
The experimental ponds generally supported
populations of Tanytarsini and Chironomini
midges.Speciesof Tanytarsini were predominant but specific identifications could not be
made due to the lack of taxonomic keys. Among
Chironomini, ChironomusdecorusJohannsen,
Chironontusstigmaterus Say, Goeldichironontus
holoprasinus (Goeldi), PolypediLum paruunx
Townes and Apedilum elachistusTownes were
recognized,but most of these speciesoccurred
in numbers too small to assesseffectivenessof
methoprene against individual species; therefore, they were all combined under the tribe,
Chironomini. Speciesof Tanypodinae,Ablnbesmyia mallachi (Walley), Coelotanypttsconcinnus
(Coquillett) and Tanypus neopunctipennrsSublette were collected in negligible numbers in a
few samples,forming <1-2Vo of the total midges
collectedon any samplingoccasion.
The effects of different formulations and/or
treatment rates of methopreneon chironomid
emergencefrom the ponds can be elucidated
from the pretreatment and the periodic posttreatment data on Tanytarsini, Chironomini
and total midges presentedin Table 2. The low
rate of A.L.L. (0.015kg AI/ha) was ineffective
but at the high rate of 0.28 kg Al/ha, A.L.L.
induced complete inhibition of emergence of
Tanytarsini and Chironomini within 3 and 7
days of posttreatment, respectively. Overall,
A.L.L. at the high rate suppressedemergenceof
adult Tanytarsini, Chironomini, and total
midgesby 84-t00%, 30-100% and 74-99%, respectively,during the 2 wk posttreatment period
(Fig. 1). Emergencereturned to pretreatment
Ievels or higher in the 3rd wk after treatment.
The granular formulation of methopreneat 0.17
kg AI/ha produced 45-87%,73-100%and 6187Vo confto| of Tanytarsini, Chironomini and
total midges, respectively, during 2 wk after
treatment.
The effectivenessof granular formulation was
lost in the 3rd wk after treatment. Altosidpellets
Table 1. List of test formulations, application rates and percent active ingredient of methopreneapplied to
experimental ponds, Sanford, FL (April 27, L990).
Formulations
%(S)-methoprene
Application rate
AIl equivalent
A,L.L.,
A.L.L.
SAN 81OI 1.3GR
Altosid pellet
Altosid XR briquet
5.0
0.293liter/ha
5.86 liter/ha
13.0kglha
5.6 kglha
1 briquet/8 m'
0.015kglha
0.28kglha
0.r7 kg/ha
0.22kg/ha
0.82kg/ha
I AI : Active ingredient.
2A.L.L.: Altosid Liquid Larvicide.
D.('
4.0
1.8
JouRNlr, oF THEArr{eRrcnNMosqurro CoNTRor,AssocrarroN
618
Fl
H i @
O ) i @
+t +t +t
+t +l +t
+t +t +t
+l +l +l
+t +t +l
+t +t +l
o)16
O
Nico
i
r o o
o ) i o
6)r(o
O
)
@
@
6
{
o i o
+t +t +l
a
o
x
o
)
@
o
r
o
@ * i
m
o
i
@
H
r
o
rcD@
+t +t +t
]
(
r
o
@ r o )
.
IoC!\O
N S N
+r +r +r
ro6i
1
r
o
m
$ @ r o
@
i c \ i
(@0 @ ( or
+t +t +l
r i @
o
( o r
r
N r o N
r i @
@ ( o 6
6 i @
N
o
O N O
C { i 6 l
(oroi
r
@
a
c
VoL. 7, No. 4
i
@c')i
0
i
c
N
c
c6rv
a
o
\or\o
+t +t +t
l
c
o){o
o
r
+t +r +l
o
(
+
d N H
<)ni
o
H
+t +t +l
i
N
a
+t +t +t
+t +t +t
+t +t +t
+t +t +l
+t +t +l
6
i o ) *
(O
r
N i c 6
t.-Nor)
r @ 6
(]f
rO
i N m
i
N
6
( o ( ! o
i s N
N N o
N i c D
o o ) i
3 i ( O
o
i d o )
+t +t +r
+r +r +t
+t +t +t
+t +t +l
+t +t +l
+t +i +l
6 N f f n N
< O ) O
S
6
r O r
m i <
O ) i O
O ) o N
r@lo
< 0 i @
iN
Oid
(O
O
o)O)o)
N c ' ) i
i O i
r i @
o m r
roi(l)
N
a
o
(!
o
@
N
o
o
o
o
u
^
B
\\
i o i
i
<!
9
o
-
^
t
\1n65
>
N
q
^
o
S o ) n
^
t
@ m c o
{
| + r + r +Ir + r + r +!r + r + r +€r + r + r +j r +t +t +t
{ r : r
- door :
6 NH<
! N N m
.
a
o
d
\ - N H N
6
a
^
566o:6 5n
y) iNm
S d *
o
,
i N F
e
;
^
- i
t *
(F: o
) Sn . o $
*\
><om o,
<
S
N
i
N
]^
-i"
O
s
S
*
I s * E i * - - ?g ^ s i = - P Y
o
r 3 r
S + r + r +i r + r + r +t r + r + r +t r + r + r +Sr +l +t +t
-B
a
a
.:
ca@i
caFrn
:
i . v
+ d
(g
'i
a
+l
.
F
.
j
@
\
o
o
,o
o
o
Q
i
$61(o
iiN
*
N
A
d
A
FnE6
1
R
i
?- c r
N o N
s i $
o
S
t
\
o
cam(o
rn
rO
R
tE
_
T s
r
E
@ O @
\
t
t(t61[i
;
<
+t +r+l
e
E
6
o
N $ 6 n
&
i)
^
6m@
:
c :
O i N
i c r ) i
+t +t +l
OJroto
ro.+ O
i
N
E
.+Nro
o)(oi
+ t + t + t + t + t + t : + r + r + r + r + l + l +t +t +t
+t +t +l
i O r O
irN
s
< $ @
@ c a i
$ \ o
H c ) i
E
<
N
N
(
5
r O S
O)
O)
O ) m N
N
Cn
c o o i
m m m
o N N
c o $ c a
m N.+
$ o I o
i d i
+r +t +t
+t +t +r
+l +r +l
+r+r+l
+t +t +t
+r +t +l
O)(OrO
i
C\.+
o
m
OHi
i(OFcD
m
c6 6.1 ro
Loroi
r
@
c€\o@
o ) N i
$
i
@ i o
F - N @
ri
I
o
o
ONco
roo)
O)
S
6lrN
m3cQ
303
N
rr)lo0)
c9clro
(.oca@
o)gi
+t +t +t
+t +t +t
+l +l +l
+l +l +l
+t +t +r
+t +t +l
\oroo
r { I
r(gco
{ dc o
m@6t
6o6
ooo
6m co
\o(l)i
@{lm
i
o
o
o
o
,9
d
€ A? i o
ra^? x d
t a? E {
€ F -q
? E
FOF
F(.)F
F()F
FOF
H P
o
F
F
.-'a
'7-8
H 9
.-'=
'68
.-'e
'6E
.-'=
'6',8
h P
b P
o
'68
'6E
€6 X: -
€6 =^ -
L
L
a E a
T \
L
a E a
f i L
,
o
DECEMBER1991
-o
NEw F0RMULATIoNS or MotnopnrNs
a
A.L.L.(0.293 lltcr!/ha or 0.015 kg Al/hr)
SI
A.L.L.(5.8Cllicr!/hr or 0.28 ke Al/h.)
@
SAll 810 I r3 Gn (13.0 ke/hr or O.l7 19 AUha)
-
(l Brlqu.t/t m' or o.t2 I! Al/ht)
aLTOSIDXR BRIOUETS
I
ALTOSIDPELLETS(5.6 kg/ha or 0.22 k9 al/h.)
"
F
6 roo
-- 6
0
U
O
rn
2 - U
E o o
U
I
u
F
U
20
o
U
4
80
s
7
oil, ,l"r.r".or*r",
Fig.1.Percentinhibitionof emergence
of Tanytarsini, Chironominiandtotal midgeadultsdueto treatmentswith different formulationsand rates of the
(Altosid)to experimental
pondsat
IGR methoprene
the Universityof Florida'sCentralFloridaResearch
andEducationCenter,Sanford.
at 0.22kg AI/ha gaveinitial and prolonged good
control of Tanytarsini (64-99% for 7 wk), Chironomini (79-94% for 5 wk), and total midges
(64-98% for 7 wk). Altosid XR briquet formulation was also effectiveyielding 53-97%control
of Tanytarsini for 5 wk, 39-96% control of Chironomini for 6 wk and 38-98% control of total
midges for 7 wk posttreatment. Although the
rate of application(0.82kg AI/ha) of the briquet
formulation was almost 4x higher than that of
the pellet formulation, the latter formulation
gavebetter midge control.
Analysis of variance indicated that differences
in suppressionof adult midge emergencebetween methopreneformulations and times posttreatment were both highly sigrrifrcant (P <
0.01). Interaction betweenthese 2 factors was
insignificant (P > 0.1). Multiple comparisons
revealedthat the pellets and briquets were the
only formulations which significantly reduced
midge emergencecomparedwith the controls (P
< 0.01),and reducedit for longer periods of time
than the other formulations tested. The high
rate of A.L.L. (0.28 kg AI/ha) gave excellent
initial control, but provided limited residual activity. The granular formulation also resulted in
relatively short-lived residual activity. This formulation at 13.0 kglha (or 0.17 kg AI/ha) did
not sustain and deliver sufficient active ingredient for effective,Iong-term midge control. The
more "efficient" performanceof the pelletsthan
the briquets may be attributable to more uniform coverage(0.22 m2/pellet vs. 8 m2/briquet)
and the difference in rate of releaseof the active
ingredient from the 2 formulations. The latter
phenomenoncan be influencedby the formulation's hardness,its size and the surfacearea to
volume ratio of the particles.
There are limited reports on the freld use of
methoprene against midges. Mulla and Darwazeh (1975)reported marginal control of.Cricotopus, Tanytarsus and Paralauterborniella
midges in experimentalponds with 2 slow-release (SR) Altosid liquid formulations, SR-10
and SR-10F,eachappliedat the rate of 0.11kg
AI/ha. Mulla et al. (1974)evaluatedan emulsifiable and 2 encapsulatedSR flowable formulations (a 5% AI sinking type and a l0% AI
floating type) of Altosid (ZR-515)in small outdoor box plots, in experimental ponds and in a
man-made residential-recreationallake. In box
plots and ponds, emergenceof Chironominae
and Tanypodinae was suppressedfor 1-3 wk
with methopreneat concentrationsof 0.1-0.2
ppm. The SR formulations proved superior to
the emulsifiable formulations in terms of
suppressionof adult emergenceand residual activity. In the lake,both SR formulationsat 0.28
kg AI/ha, producedsimilar results,inducing inhibition of Chironomus, Tanytarsus and Procladius midgesfor 2 wk. Repeatedtreatments of
the lake with Altosid SR-10 gave 1-3 wk of
midge control, with the duration of control becomingshorter on successive
treatments(Mulla
et al. 1976):the SR-10and SR-10Fformulations
at 0.28 kg AI/ha were almost equally effective.
The results of Mulla et al. 1974) in the lake
are comparableto the magnitude and duration
of midge control (74-99% for 2 wk posttreatment) producedby A.L.L. appliedat0.28 kg AIl
ha in the present study. The limited residual
activity of the liquid formulations used previously (Mulla et al.1974,1976)and in this study
is due to the relatively short half-life (ca. 2 h) of
methoprene in water (Schaefer and Dupras
1973).The gradualreleaseof this compoundin
water for prolonged residual activity has been
JouRttll oF THEArr,rnnrcaN
Moseurro CoNrnol AssoclnrtoN
achieved through formulation improvement as
shown in the present study where the pellets on
a lower AI basisthan A.L.L. (0.22ke Allha vs.
0.28 kg Allha) produced 64-98% control of
midges for 7 wk posttreatment.
New solid formulations of methoprene have
displayed superior biological and prolonged residual activity against chironomids.This compound is relatively safe to nontarget organisms
in the aquatic environment (Miura and Takahashi 1973,Mulla et al. 1979).These attributes
make some formulations of the IGR, methoprene, potentially an excellent additional tool
for midgecontrol.
VoL. 7, No. 4
shallow residential-recreational lake in southern
California.Mosq. News 38:528-535.
Elliott, J. M. 1977.Some methodsfor the statistical
analysesof samplesof benthic invertebrates.Freshwater Biol. Assoc..Sci..Publ. 25.
Johnson, G. D. and M. S. Mulla. 1981. Chemical
control of aquatic nuisance midges in residentialrecreationallakes.Mosq. News 41:495-501.
Miura, T. and R. M. Takahashi. 1973.Insect development inhibitors. 3. Effects on nontarget aquatic
organisms.J. Econ. Entomol. 66:917-922.
Mulla, M. S. f974. Chironomidsin residential-recreational lakes. An emerging nuisance problemmeasures for control. Entomol. Tidskr. 95
(Suppl.):172-176.
Mulla, M. S. and H. A. Darwazeh.1975.Evaluationof
insect growth regulatorsagainst chironomids in experimental ponds. Proc. Pap. Calif. Mosq. Control
ACKNOWLEDGMENTS
Assoc.43:164-168.
This is Florida Agricultural Experiment Sta- Mulla, M. S., W. L. Kramer and D. R. Barnard. 19?6.
tions Journal Series No. R-01565.The assistInsect growth regulators for the control of chironanceof M. L. Kok-Yokomi during the courseof
omid midges in residential-recreational lakes. J.
this study is acknowledged.
Econ.Entomol. 69:285-291.
Mulla, M. S., G. Majori and A. A. Arata. 1979.Impact
of biological and chemical mosquito control agents
REFERENCESCITED
on nontarget biota in aquatic ecosystems.Residue
Ali, A. 1980.
Dieladulteclosion
periodicity
of nuisance Rev.71:121-173.
chironomid
midges
of centralFlorida.Environ.En- Mulla, M. S., R. L. Norland,T. Ikeshoji and W. L.
tomol.9:365-370.
Kramer. 1974.Insect growth regulatorsfor the conAli, A. 1991.Perspectives
trol of aquatic midges. J. Econ. Entomol. 67l.167on managementof pestiferous Chironomidae (Diptera), an emerging global
170.
problem.J. Am. Mosq. Control Assoc.?:260-281.
Mulla, M. S., R. L. Norland. D. M. Fanara. H. A.
Ali, A. and M. S. Mulla. 1977.The IGR diflubenzuron
Darwazehand D. W. McKean. 1971. Control of
and organophosphorusinsecticidesagainst nuisance
chironomid midgesin recreationallakes.J. Econ.
midgesin man-maderesidential-recreational
Entomol. 64:300-307.
lakes.
J. Econ. Entomol. 70:571-577.
Pelsue,F. W. and G. C. McFarland.1971.Laboratory
Ali, A. and M. S. Mulla. 1978.Decliningfield efficacy
and field studieson a new chironomid speciesin the
of chlorpyrifosagainstchironomidmidgesand labSoutheastMosquito Abatement District. Proc. Pap.
oratory evaluation of substitute larvicides. J. Econ.
Calif. Mosq. Control Assoc.39:74-79.
Entomol. 7l:.778-782.
Schaefer,C. H. and E. F. Dupras, Jr. 1973. Insect
Ali, A., M. S. Mulla, A. R. Pfuntner and L. L. Luna.
developmentinhibitors.4. Persistenceof ZR-515in
1978. Pestiferousmidges and their control in a
water. J. Econ. Entomol. 66:923-927.